First Break September 2023 - Reservoir Engineering & Geoscience by EAGE

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SPECIAL TOPIC

Reservoir Engineering & Geoscience EAGE NEWS Oslo 2024 planning is underway TECHNICAL ARTICLE Multi-scenario deep learning 4D inversion

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FIRST BREAK® An EAGE Publication

CHAIR EDITORIAL BOARD Gwenola Michaud (Gwenola.Michaud@cognite.com) EDITOR Damian Arnold (arnolddamian@googlemail.com) MEMBERS, EDITORIAL BOARD • Lodve Berre, Norwegian University of Science and Technology (lodve.berre@ntnu.no) • Philippe Caprioli, SLB (caprioli0@slb.com) • Satinder Chopra, SamiGeo (satinder.chopra@samigeo.com) • Anthony Day, PGS (anthony.day@pgs.com) • Peter Dromgoole, Retired Geophysicist (peterdromgoole@gmail.com) • Kara English, University College Dublin (kara.english@ucd.ie) • Stephen Hallinan, CGG Stephen.Hallinan@CGG.com • Hamidreza Hamdi, University of Calgary (hhamdi@ucalgary.ca) • Clément Kostov, Freelance Geophysicist (cvkostov@icloud.com) • Pamela Tempone, Eni (Pamela.Tempone@eni.com) • Angelika-Maria Wulff, Consultant (gp.awulff@gmail.com) EAGE EDITOR EMERITUS Andrew McBarnet (andrew@andrewmcbarnet.com)

Optimising reservoir development and asset value using unified ensemble modelling

Editorial Contents 3

EAGE News

Personal Record Interview — Dr Robert Laws

Crosstalk

Industry News

MEDIA PRODUCTION Saskia Nota (firstbreakproduction@eage.org) PRODUCTION ASSISTANT Ivana Geurts (firstbreakproduction@eage.org) ADVERTISING INQUIRIES corporaterelations@eage.org EAGE EUROPE OFFICE Kosterijland 48 3981 AJ Bunnik The Netherlands • +31 88 995 5055 • eage@eage.org • www.eage.org EAGE MIDDLE EAST OFFICE EAGE Middle East FZ-LLC Dubai Knowledge Village Block 13 Office F-25 PO Box 501711 Dubai, United Arab Emirates • +971 4 369 3897 • middle_east@eage.org • www.eage.org EAGE ASIA PACIFIC OFFICE UOA Centre Office Suite 19-15-3A No. 19, Jalan Pinang 50450 Kuala Lumpur Malaysia • +60 3 272 201 40 • asiapacific@eage.org • www.eage.org EAGE AMERICAS SAS Edificio Centro Ejecutivo Santa Barbara Av. Cra. 19 #118-95 - Office: 501 • +57 310 8610709 • americas@eage.org • www.eage.org EAGE MEMBERS CHANGE OF ADDRESS NOTIFICATION Send to: EAGE Membership Dept at EAGE Office (address above)

Technical Article 29

Multi-scenario deep learning 4D Inversion: A Brazil pre-salt case study Yang Xue, Dan Clarke and Kanglin Wang

Robust and high resolution imaging of limited-aperture DAS VSP Herurisa Rusmanugroho and Makky Sandra Jaya

Special Topic: Reservoir Engineering & Geoscience 45

Offshore Uruguay: Big hopes (and supporting geology) for the Cretaceous Bruno Conti, Rodrigo Novo, Josefina Marmisolle, Pablo Rodríguez and Pablo Gristo

Optimising reservoir development and asset value using unified ensemble modelling Sebastien Strebelle and Martha Stunell

Accelerating insights from 4D seismic data with new multi-dimensional data structures Bill Shea, Jorg Herwanger and Peter Harris

RGT-based multi-channel matching pursuit: a fast and stable spectral decomposition method Lory Evano and Fabien Cubizolle

Time-lapse gravity and subsidence applied in history matching of a gas-condensate field Øystein Haugen Solbu, Asgeir Nyvoll, Håvard Alnes, Siri Catherine Vassvåg, Martha Lien and Hugo Ruiz

Screening for AVA anomalies in siliciclastic basins: testing a seismic inversion method in the Mississippi Canyon, Gulf of Mexico David Went, Richard Hedley and Jon Rogers

Closed-loop single well geothermal solution Kim Gunn Maver, Ola Michael Vestavik, Jørgen Peter Rasmussen and Carl-Emil Larsen

Hacking the source rock code in Nova Scotia’s deep water Natasha MacAdam, Karyna Rodriguez, Neil Hodgson, Catie Donahue and Graham Spence

FIRST BREAK ON THE WEB www.firstbreak.org

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ISSN 0263-5046 (print) / ISSN 1365-2397 (online)

Using Self-Organised Maps to analyse seismic illumination of CO2 storage reservoirs Dr Bob Hardage

Calendar

cover: Multichannel matching pursuit technique guided by a Relative Geological Time model, which features in our Reservoir Engineering & Geoscience Special Topic this month. (photo courtesy of Eliis)

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European Association of Geoscientists & Engineers

Board 2023-2024

Near Surface Geoscience Circle Esther Bloem Chair Andreas Aspmo Pfaffhuber Vice-Chair Micki Allen Contact Officer EEGS/North America Adam Booth Committee Member Hongzhu Cai Liaison China Deyan Draganov Technical Programme Officer Wolfram Gödde Liaison First Break Hamdan Ali Hamdan Liaison Middle East Vladimir Ignatev Liaison CIS / North America Musa Manzi Liaison Africa Myrto Papadopoulou Young Professional Liaison Catherine Truffert Industry Liaison Mark Vardy Editor in Chief Near Surface Geophysics Florina Tuluca Committee member

Oil & Gas Geoscience Circle Edward Wiarda President

Laura Valentina Socco Vice-President

Pascal Breton Secretary-Treasurer

Caroline Le Turdu Membership and Cooperation Officer

Peter Rowbotham Publications Officer

Yohaney Gomez Galarza Chair Johannes Wendebourg Vice-Chair Lucy Slater Immediate Past Chair Erica Angerer Member Wiebke Athmer Member Tijmen Jan Moser Editor-in-Chief Geophysical Prospecting Adeline Parent WGE & DET SIC liaison Matteo Ravasi YP Liaison Jonathan Redfern Editor-in-Chief Petroleum Geoscience Aart-Jan van Wijngaarden Technical Programme Officer

Sustainable Energy Circle Carla Martín-Clavé Chair Giovanni Sosio Vice-Chair

SUBSCRIPTIONS First Break is published monthly. It is free to EAGE members. The membership fee of EAGE is € 80.00 a year including First Break, EarthDoc (EAGE’s geoscience database), Learning Geoscience (EAGE’s Education website) and online access to a scientific journal.

Maren Kleemeyer Education Officer

Aart-Jan van Wijngaarden Technical Programme Officer

Esther Bloem Chair Near Surface Geoscience Circle

Companies can subscribe to First Break via an institutional subscription. Every subscription includes a monthly hard copy and online access to the full First Break archive for the requested number of online users. Orders for current subscriptions and back issues should be sent to EAGE Publications BV, Journal Subscriptions, PO Box 59, 3990 DB, Houten, The Netherlands. Tel: +31 (0)88 9955055, E-mail: subscriptions@eage.org, www.firstbreak.org. First Break is published by EAGE Publications BV, The Netherlands. However, responsibility for the opinions given and the statements made rests with the authors. COPYRIGHT & PHOTOCOPYING © 2023 EAGE All rights reserved. First Break or any part thereof may not be reproduced, stored in a retrieval system, or transcribed in any form or by any means, electronically or mechanically, including photocopying and recording, without the prior written permission of the publisher.

Yohaney Gomez Galarza Chair Oil & Gas Geoscience Circle

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PAPER The publisher’s policy is to use acid-free permanent paper (TCF), to the draft standard ISO/DIS/9706, made from sustainable forests using chlorine-free pulp (Nordic-Swan standard).

Carla Martín-Clavé Chair Sustainable Energy Circle

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HIGHLIGHTS

GET2023 energy transition focus

Laurie Dake Challenge winners announced

What Digital 2024 has in store

A special EAGE Annual Conference is planned for 2024 in Oslo As chair of the local advisory committee for the 2024 EAGE Annual Conference & Exhibition, Erling Vågnes, SVP subsurface exploration production international, Equinor, offers this welcome to next year’s Annual in Oslo.

Erling Vågnes, chair local advisory committee.

Following a very successful and well attended 84th EAGE conference in Vienna, it is with great pleasure that I invite you to the 85th EAGE Annual Conference & Exhibition in Oslo. We are delighted to welcome the EAGE Annual back in Norway after 20 years. The theme chosen for the conference – ‘Technology and talent for a secure and sustainable energy future’ – sums up the most important contribution by our EAGE community to the societies we live and work in.

Short-term, secure and affordable access to oil and gas is a prerequisite for the welfare of a growing global population. Longer term, a transition to a dominantly renewable-based energy system with mitigation of remaining carbon emissions is a prerequisite for a habitable planet for that growing population. In my professional work with Equinor, I am encouraged and proud to observe how geoscientists and engineers are contributing to solve both the shortand long-term challenges. Norway and Norwegian industries are working hard to contribute to both short-term security and affordability of energy supply and to solving the longerterm sustainability challenge through transforming the Norwegian Continental Shelf from an oil and gas province to a broad energy province. These efforts will

provide important perspectives for our strategic programme. First and foremost, as always, the Conference will be an opportunity to showcase the best of the geosciences from not only within Europe, but globally. Also, to interact, share and explore ideas and argument and not least build the networks we will need to meet future resources needs. As ever we anticipate a broad and balanced Technical Programme built on in-depth discipline knowledge, technical integration for holistic solutions and cross-fertilisation between oil & gas, CCS, renewables and infrastructure geosciences. Finally, we plan to facilitate discussions on the dilemmas and opportunities impacting the geosciences in a rapidly changing world. We look forward to your participation in Oslo on 10-13 June 2024.

Stay informed about new developments in the build-up to the 2024 Annual by checking our website www.eageannual.org regularly.

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EAGE NEWS

Bangladesh scene wins 2023 Photo Contest Nazmus Zaqeb with his photo ‘Plastic recycling worker in Bangladesh’ taken in Rangpur, Bangladesh was this year’s winner of the ‘Legends of Geoscience’ photo contest held jointly by EAGE and the European Federation of Geologists (EFG). Second and third places went to Ayesha Ejaz, for her photo ‘I need some mountain time’ taken in Khunjerab Pass, Pakistan, and M.A. Omar Naseef, for ‘Gardmore River’ taken in Sri Lanka. For his winning photo Zaqeb receives a three-credit education package that can be redeemed with any available EAGE online courses of his choice. He commented that ‘according to the World Bank, in December 2021, Bangladesh was one of the top countries in the world in terms of plastic pollution’, so portraying ‘the importance of plastic recycling will make people aware of the different uses they can give to this material, even storing or selling it, instead of throwing it anywhere. By doing this, the environment will be saved from disaster to some extent’. The second and third place contestants receive a complimentary registration to join an EAGE online course, too. Through our Interactive Online Short Courses, Extensive Online Courses, Online EETs and Self-Paced Courses, they can update and strengthen their knowledge in various disciplines, while they earn CPD (Continuing Professional Development) points. These can be used to claim or maintain European Geologist (EurGeol) titles accredited by EFG. This year, EAGE members and EFG-affiliated associations were invited to capture extraordinary actions or aspects in all fields of geoscience. The photos were presented under the following categories:

‘Plastic recycling worker in Bangladesh’ – Nazmus Zaqeb.

Sustainability in geosciences, Landscape and environment, Women geoscientists, Working together in geosciences, Digitalisation and innovation, and the New generation of geoscientists. The geoscience and engineering community was invited to submit their entries from January to March 2023. The photos received came from 29 different countries: Algeria, Angola, Bangladesh, Belgium, Bolivia, China, Colombia, Czech Republic, Denmark, Egypt, Estonia, Ethiopia, France, Germany, Greece, Greenland, Guatemala, Iceland, India, Indonesia, Iran, Italy, Pakistan, Oman, Saudi Arabia, Spain, Sri Lanka, Ukraine and the United States. The admitted entries went through a first voting round in March. The top 12 pictures were exhibited at the 84th EAGE Annual Conference and Exhibition and then presented for a second voting round in July, where the three winners were selected.

‘I need some mountain time’ – Ayesha Ejaz.

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The 12 finalist photos were: Amitava Chandra: ‘Floating Veg-market’ – Kashmere, India; Alberto Sanchez Miravalles: ‘Exploring’ – Asturias, Spain; Alireza Malehmir: ‘Innovation for climate action’ – Havnso area in Denmark; Carmen Corbalán Andreu: ‘Krafla geothermal power plant’ – Iceland; Denis Martin Schlatter: ‘Exploring for Ni-Co-Cu-PGE in West Greenland’ – Nuussuaq Peninsula, West Greenland; Marko Komac: ‘Amazing ornamental quarry’ – Quihita, Angola; Menal Gupta: ‘Beauty meets Brain & Brawn’ – Italian Dolomites; Peeter Paaver: ‘Drill cores’ – Estonia; and Zahra Tajmir Riahi: ‘Living under the shadow of active faults!’ – Isfahan city, Iran. Congratulations to the participants and thanks to all the members that, with their vote, helped us to choose this year’s ‘Legends of Geoscience’. Submissions for the EAGE/EFG Photo Contest 2024 will begin on 1 January.

‘Gardmore River’ - M.A. Omar Naseef.

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EAGE NEWS

GET2023 sessions to highlight challenge of sustainable energy transition In an era marked by environmental concerns and the urgent need for sustainable energy, the global energy industry faces critical challenges. Our Global Energy Transition Conference & Exhibition – GET2023 – in Paris on 14-17 November provides a unique platform for researchers, practitioners, policymakers, and business stakeholders to come together and address these challenges. As the demand for energy continues to rise, so do the challenges that the sector must grapple with. Today, the

Ellie MacInnes, GET2023 conference chair says, ‘As we transition towards sustainable energy sources, we are at the forefront of the implementation of diverse projects, from coastal geothermal to hydrogen and beyond. Seasoned oil and gas professionals realise the value of their technical subsurface skills in this new landscape. Our pivotal role lies in bridging the gap between tradition and innovation, combining innovative technologies with project management, risk analysis, and multi-disciplinary integration. As geoscientists and engineers, we play a pivotal role in bridging the gap between traditional practices and cutting-edge solutions.’

energy sector undergoes a paradigm shift, with a focus on decarbonisation and renewable technologies. This transition requires adaptable decision-making to align with long-term sustainability goals. By fostering dialogue and collaboration, the conference enables an honest conversation about the actions required to deliver a responsible and just transition. The technical programme at GET2023 features strong themes centred around carbon capture and storage (CCS) and hydrogen technologies. This demonstrates the quality of research and development currently shaping the energy sector. The tangibility and the increasing recognition of the technology is evident with significant commercial interest. Within the technical programme, the focus is to effectively communicate the success and progress made thus far. This year, GET introduces dedicated sessions featuring keynote speakers who will discuss crucial topics shaping the energy transition, highlighted here. Recent developments in carbon storage regulation: As CCS gains prominence as a crucial component in achieving net-zero emissions, understanding the changing regulations becomes essential for successful project implementation. Keynote speakers will share their expertise and insights, highlighting the regulatory developments

Networking opportunities to share experiences and insights with fellow participants.

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Last year saw big attendance.

in CCS technologies in multiple countries. Attendees will gain a comprehensive understanding of the legal and regulatory frameworks necessary to facilitate safe and efficient carbon storage practices. Mining and critical minerals: As the demand for new technology for the energy transition surges, so does the need for critical and strategic minerals. However, supply challenges and potential resource constraints pose significant obstacles to widespread adoption. In this session, keynote speakers will discuss how to secure a sustainable metal supply and EU sovereignty, a focus on the demand for the energy transition, the potential resources for critical minerals in Europe as well as innovative solutions that could tackle some of the challenges in mining and critical minerals. Insights from implementation of CCS flagship projects: The session offers an opportunity to learn from the experiences of regulators, operators, and stakeholders involved in these projects. Keynote speakers will share valuable lessons, best practices, and strategies that have led to successful carbon storage. Participants should gain insights into prospect and storage site identification, effective stakeholder engagement, and the use of innovative technologies. By addressing these key areas within the conference, we strive to make significant contributions to the sustainable energy transition. Secure your spot at a lower fee by registering before 31 October 2023. For event details and sponsorship opportunities, visit www.eageget.org.

EAGE NEWS

CCS short course is creating a buzz A great new addition to EAGE’s Short Course Catalogue is ‘Basics of carbon capture and storage (CCS): a course for geologists, geological regulators, policy makers and investors’ presented by Prof Mike Stephenson, former chief geologist, British Geological Survey and well-known science communicator. The course is designed for various stakeholders who need to be up to date and unbiased information on CCS and was first offered onsite during the EAGE Annual Conference in Vienna. It was well received with over 100 participants in attendance, some of whom were eager to share their enthusiasm about the course:

‘When I returned to work this week, I got swamped by the daily grind, but I could not let myself forget to thank you for the follow up information and again say how much I enjoyed your course’ … ‘Thanks for the wonderful short course today. The seven hours flew by’ … ‘Thank you for that great course and overview on all those topics’. The online version of the course also received praise. One participant, Bilal Tariq (Oil and Gas Development Company, Pakistan), said: ‘The course was very well structured and well delivered by Prof Mike Stephenson. I will highly recommend it if anyone wants a comprehensive introduction to CCS’.

The course is available again onsite at the GET2023 event in Paris. Scheduled on 14 November, the day will cover topics such as geological carbon cycle, capturing and transporting CO2, geological storage, leakage and monitoring, and public view of CCS. Register now and discover what the buzz is all about at eageget.org/shortcourse.

IPTC offers opportunity to join energy transition conversation

King Abdulaziz Centre for World Culture, Dhahran.

The long-established International Petroleum Technology Conference (IPTC) is expected to attract more than 18,000 participants when it returns to Dhahran Expo, Saudi Arabia in February 2024. Founded in 2005, IPTC continues to be a flagship multi-disciplinary technical event in the Eastern Hemisphere. The knowledge, capabilities and strengths of the participating countries and the spon-

soring societies’ global membership are central to the success of the conference and exhibition. Don’t miss this prime opportunity to connect with senior decision makers, industry leaders and innovators who will spearhead the energy transition. Learn more about this topical event by getting in touch with Diya Sapru at ssu@eage.org.

EAGE Online Education Calendar 5 SEP 5 OCT

NON-SEISMIC DATA ACQUISITION AND PROCESSING: GRAVITY & MAGNETICS BY JAAP MONDT

EXTENSIVE ONLINE COURSE

14 HRS (INCL 7 WEBINARS OF 1-2 HRS EACH)

20-21 SEP

BEYOND CONVENTIONAL SEISMIC IMAGING BY EVGENY LANDA

INTERACTIVE ONLINE SHORT COURSE

4HRS/DAY, 5 PARTS

25-26 SEP

SEISMIC RESERVOIR CHARACTERIZATION: AN EARTH MODELING PERSPECTIVE BY PHILIPPE DOYEN

INTERACTIVE ONLINE SHORT COURSE

4 HRS/DAY, 7 MODULES

26-28 SEP

CASE STUDIES AND PRACTICAL CONSIDERATIONS IN GEOPHYSICAL ACQUISITION AND PROCESSING METHODS BY LUCA DE VINCENZI

INTERACTIVE ONLINE SHORT COURSE

4 HRS/DAY, 9 PARTS

* EXTENSIVE SELF PACED MATERIALS AND INTERACTIVE SESSIONS WITH THE INSTRUCTORS: CHECK SCHEDULE OF EACH COURSE FOR DATES AND TIMES OF LIVE SESSIONS FOR THE FULL CALENDAR, MORE INFORMATION AND REGISTRATION PLEASE VISIT WWW.EAGE.ORG AND WWW.LEARNINGGEOSCIENCE.ORG.

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EAGE NEWS

OUR JOURNALS

THIS MONTH

Geophysical Prospecting (GP) publishes primary research on the science of geophysics as it applies to the exploration, evaluation and extraction of earth resources. Drawing heavily on contributions from researchers in the oil and mineral exploration industries, the journal has a very practical slant. A new edition (Volume 71, Issue 7) will be published in September featuring 16 articles. Editor’s Choice articles: • A workflow for processing mono-channel Chirp and Boomer surveys – A. Vesnaver et al. • A review and analysis of errors in post-stack time-shift interpretation – C. Macbeth et al. • On pathological orthorhombic models – A. Stovas et al.

CHECK OUT

THE LATEST GP

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Latin America to host EOR and seismic workshops in 2024 Watch out for two upcoming EAGE events in Latin America which have already made a name for themselves. We are holding a third version of our workshop on ‘Advanced seismic solutions in the Gulf of Mexico’ in Mexico City on 5–6 September 2024. The Gulf of Mexico is a remarkable region to study oil and gas activity, as it archives extensive seismic data, geologic interpretations, block leasing information and so on. Although the primary focus of the workshop will be on this region, strong links will be maintained with adjacent areas of interest to explorers. Meanwhile, our established workshop on enhanced oil recovery (EOR) in the Americas is being planned for 3-4 October 2024 in Buenos Aires. This third edition is expected to address new ideas, trends, and experiences covering all phases of an EOR project including research, planning, field implementation, and surveillance, as well as offering new fundamental and practical insights into the EOR methods. As existing oil fields mature, including unconventionals, EOR methods have been

The Third EAGE Workshop on EOR in the Americas will take place in Buenos Aires, Argentina, for the first time.

gaining significant momentum globally. That’s why this event will be an excellent opportunity to join the conversation and get acquainted with first-hand experience from successful operators, service companies, government representatives and academia. Mark your calendar and get ready to showcase your research in our workshops. The call for abstracts will open soon.

Check the technical programme for upcoming HPC event in Lugano The technical programme for our Seventh High-Performance Computing Workshop, being held in Lugano on 25-27 September, is now available. The event aims to provide a platform for experts in the field to share their knowledge and insights regarding the state-of-the-art applications in the upstream industry. Through oral presentations, participants will have the opportunity to showcase their research, projects, and advancements in utilising high-performance computing for various aspects of the energy business. Keynote speeches by industry leaders will provide valuable insights into the latest trends, innovations, and future directions of high-performance computing in the context of the energy transition. The exciting technical programme is now available. Secure your spot and be at the forefront of innovation!

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EAGE NEWS

Interpretation terminator: Rise of the machines? At the EAGE Annual in Vienna, the Seismic Interpretation Community convened in person for the first time since the pandemic, sparking a lively discussion on the role of artificial intelligence (AI) in seismic interpretation. Members of the committee of the SI Community met with participants from both operators, such as Equinor and Wintershall DEA, and service providers. This is a short summary of the discussion. The participants acknowledged the tremendous value of machine learning (ML) tools for fault detection, emphasising that it would be a missed opportunity not to utilise them. However, they also recognised that the performance of ML models in horizon interpretation heavily relies on the quality of the data. Challenging factors like complex horizons and noisy data pose obstacles for both auto-tracking algorithms and ML. Nevertheless, the true potential of ML emerges when multiple surveys need to be interpreted simultaneously, demonstrating its capability to handle large-scale interpretations efficiently.

Members of the committee of EAGE’s Seismic Interpretation Community (from left to right): Nicolas Daynac (Eliis), James Lowell (Geoteric), Brian Eslick (Total Energies), Anita Torabi (University of Oslo), Anastasiia Jacobsen (Bluware), Victor Aarre (SLB).

Expanding horizons The scope of ML in seismic interpretation extends beyond data interpretation alone. It can be instrumental in automating loading procedures, predicting missing metadata (e.g., coordinate system, index byte locations), understanding vintage seismic data, and querying seismic acquisition and processing reports to assess their impact on the final seismic image. These applications showcase the versatility and wide-ranging potential of ML in geoscience.

Similar to human interpreters who may have different interpretations, ML models can exhibit variations in their predictions for the same data. To address this challenge, participants explored approaches such as ML voting, where multiple models provide their predictions, allowing interpreters to focus on discrepancies for further investigation. Creating probability cubes is another method, filtering outcomes based on statistical thresholds (e.g., 50% chance of fault presence). Increasing trust in ML is essential for its broader adoption. While seismic interpretation inherently involves ambiguity and diverse interpretations, ML can generate similar reports to human experts. Some companies already provide ML model confidence documentation, enabling specialists to identify areas that require further attention. Additionally, explainability techniques offer insights into the factors influencing ML predictions, aiding users to understand limitations and biases. By leveraging explainability, trustworthiness and reliability of ML models predictions can be enhanced. While statistics-based ML models dominate the field, the emergence of physics-based ML models is gaining attention. These models can augment data and improve accuracy, particularly when working with well data. Additionally, specialised training can enable models to recognise and exclude artefacts from seismic sections, thereby enhancing fault, horizon, and geobodies interpretations. Navigating ownership uncertainty Ownership and copyright of AI-generated images and ChatGPT text remain uncertain, causing companies to proceed FIRST

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cautiously when using tools like ChatGDP and OpenAI Codex. In seismic interpretation, a safer approach is to allow seismic data owners to train networks on their proprietary data. It is crucial for domain experts to remain involved in maintaining and fine-tuning the models, ensuring their accuracy and relevance. Efforts are underway to preserve comprehensive metadata records related to training data, engineering pipelines, processing methods, and model versions, including data ownership information. In conclusion, AI is a valuable tool that necessitates rigorous validation of results. Collaboration between seismic interpreters and data scientists is crucial, with inter-disciplinary cooperation where strict quality control is pivotal. While AI can assist in seismic interpretation, experts are still essential to navigate ambiguity and intervene when necessary. The interpreter’s job will not be taken over by AI: it will be taken over by an interpreter who knows how to work with AI.

Discussion in progress.

The committee of the EAGE Seismic Interpretation Community extends its gratitude to all participants and looks forward to continuing this dynamic discussion at the next live gathering of our community at the EAGE Annual in Oslo in June 2024. I

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EAGE NEWS

Geoscience students encouraged to look on the bright side To conclude an engaging programme at the 2nd International Summer School on Underground Hydrogen Storage in July at TU Delft, the EAGE Near Surface Geoscience Circle took the initiative to lead an online workshop for students attending the school and student members of EAGE. The workshop ‘Geoscience careers in transition’ provided a fantastic opportunity for two groups of MSc, PhD and postdocs to come together and discuss the common challenges they will face in the future. Recognising that the energy transition will be the main game-changer in the coming decades, the workshop participants reviewed the current market situation. While science and engineering solutions

studying in different parts of the world, for considering what their next steps might be. Assoc Prof Deyan Draganov (TU Delft) coordinated the programme, along with a team of experts, each representing a different type of organisation: Suzanne Hurter (University of Queensland and TNO), Matthias Imhof (ExxonMobil) and Jorien Schaaf (EBN). Students jumped at the chance to ask some burning questions. Is a background in drilling engineering useful for the energy transition, for example? The panellists concurred that yes, this is a know-how that can be applied to any type of drilling, including for geothermal energy production and hydrogen storage,

Hydrogen and wind power were discussed as green energy alternatives during the Summer School.

for renewable energy production, transportation and storage are being developed, job opportunities for green energy are still lagging behind those in the fossil-fuel-based industry. Students specialising in hydrogen storage, CO2 storage, or geothermal energy are naturally wondering what life after graduation will look like, whether a geoscience career in green energies will lead to success, and which skills will be the most valuable in securing the path forward. Participants from various countries including Turkey, Portugal, Poland, England, Scotland, Hungary, Malaysia, and Pakistan called in to discuss the issues. Many of them were studying abroad and were exploring opportunities in different countries. Some, who were in the process of applying for a PhD, found a valuable opportunity to connect with peers currently 10

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although each has its own characteristics, so continuous development is essential for jumping into any new field. All the experts involved agreed that conventional energy resources will still be needed for quite some time, even as we ‘massively develop solar and wind power’. As a result students pursuing studies in O&G today are not wasting their time and most geophysical skills are essentially transferable: from mapping and characterisation, modelling and simulations, to monitoring and data analysis. In short: the basics are the same, what students need most of all is a mindset oriented towards innovation. Participants also asked about transitioning from industry to academia (or the opposite), particularly inquiring as to which areas of learning and skills are more helpful to successfully making such

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a career move. A key learning point that emerged from this discussion is that industry and academia are complementary, and the most interesting projects are often those that involve both. Divided into teams, participants were then asked to prepare a job advertisement aimed at young professionals for one of the three types of organisations represented by the panellists (energy company, independent research institute, and governmental energy institute). The discussion that followed explored trends and concerns related to the recruitment market. Especially for entry-level geoscientists, organisations tend to look for all-round profiles. Specific tools, standards, etc can be acquired on the job. Showing an active commitment to continuous learning and the willingness to invest time into training is therefore a plus on a young professional’s resume. As big industry players are also facing a major transition, they themselves are looking for young professionals with the ability and willingness to stay flexible. In turn, the ability of a company to offer flexibility, training and retraining opportunities are things that early career professionals should look for. Clearly stating whether one has a work permit is also crucial in a fast paced and highly competitive job market, with often a majority of candidates applying from abroad. Multi-disciplinary work environments and teams are attractive too, and the ability to communicate effectively in such a context is relevant to the hiring organisations. This productive discussion ended with Matthias Imhof’s words of encouragement for the students: ‘The future is bright, be bold!’. We would like to congratulate the participants of the Summer School for completing the programme - we hope to see you again at future EAGE activities and TU Delft for the opportunity of joining forces on this activity dedicated to students. We have many other opportunities planned in the second half of 2023 for career development designed for the younger members of our Association: we look forward to supporting your next steps!

EAGE NEWS

Mature basins prospects workshop in Kuala Lumpur The joint EAGE/AAPG Workshop ‘New Discoveries in Mature Basins’ plays a pivotal role in highlighting how advances in technology and thinking have resulted in major exploration discoveries that have breathed new life to well-established petroleum provinces. The workshop will bring together experts from multiple geoscience and petroleum engineering disciplines on 30-31 January 2024 in Kuala Lumpur, Malaysia, to contribute to the advancement of this rapidly growing and impactful field. Recent years have witnessed many significant petroleum exploration discoveries in mature basins, particularly in Southeast Asia, but also around the world. Exploration in mature basins has the benefits of well-established infrastructure and extensive geoscience and engineering knowledge and experience.

However, unlocking the large hidden potential of mature provinces requires innovative solutions, such as improved imaging of deep targets, new thinking of petroleum plays and geological models, and modern engineering solutions for managing challenging subsurface drilling and development conditions. Abstract submissions on the following topics are welcome until 29 September 2023: Basin forensics, Old methods with new tools - application of geophysical and geological rigours utilising new techniques and tools, Near field exploration, The Green Deal (CCUS, non-technical considerations, economics, energy transition), and New plays, new prospects, new ideas and established basins (subtle trap hunting). At the event you can connect and network with leading industry profes-

sionals from PETRONAS, Brunei Shell Petroleum, ExxonMobil, PTTEP, Shell, and others. Learn more via https://eage. eventsair.com/workshop-on-new-discoveries-in-mature-basins/

ADDITIONS THIS MONTH The 31st International Meeting on Organic Geochemistry (IMOG 2023) on 10-15 September in Montpellier, France will bring together the best minds in the field of organic matter cycles over geological and modern time scales as well as integrated paleoenvironmental and climatic studies. Over 250 abstracts are now accessible in the proceedings on EarthDoc. We discuss a wide array of topics relating to renewable energy sources, such as hydrogen, deep ocean mining, rare earth elements, geothermal, and decarbonisation, at the EAGE Conference on the Future of Energy from 12-13 September in Kuala Lumpur. 40 papers will be presented and become available on EarthDoc. The First EAGE Conference on South Atlantic Offshore Energy Resources, to be hosted on 20-22 September in Montevideo, Uruguay, aims to promote discussion and participation around the challenges and the big opportunities that this margin hides. 30 presentations are expected, focusing on conjugate margin analogues, petroleum systems, geology and geo-tectonics, technologies applied in exploration and development, as well as environmental and regulation issues faced in the region. At IOR+2023 (2-4 October in The Hague, The Netherlands), we focus on the dynamic transitions in IOR/EOR technologies, paving the way for a future of enhanced energy recovery. 61 abstracts will be presented and become available on EarthDoc two weeks prior to the event. New issue of Geophysical Prospecting will be published in September.

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EAGE NEWS

The University of Manchester wins Laurie Dake Challenge 2023 The Laurie Dake Challenge is one of EAGE’s most prestigious student competitions. It requires participants to excel in some of the key areas of EAGE’s mission: multi-disciplinary group work, data integration, and the honing of project management, cooperation, and presentation skills.

Winning team - GeoCreate from The University of Manchester - received the prize at the Opening Ceremony of EAGE Annual 2023 in Vienna.

This year’s challenge involved analysing petroleum exploration data from various sources and evaluating its geothermal potential. The dataset provided by OMV consisted, first, of a seismic and well database focused over an area of the Vienna Basin which had been previously explored for hydrocarbons. The data supplied consisted of five 2D seismic lines crossing the basin; six inlines and crosslines extracted from a local 3D seismic survey, and six well locations with appropriate logs. This well data also included temperature measurements that could be used to directly assess the thermal gradient in the basin, and to be compared with documented average gradients from the area. Along with this information, an interpretation of the Base Neogene Basin Fill was also provided, defining the base of the sediments to be assessed. Finally, a relocated population map was provided – sitting to the south-west of the basin – for the teams to use as a basis of the development and economic planning. It was a closely contested final round, with the teams from Khalifa University and IFP School judged second and third place respectively. However, only one team could be crowned the winner of the 2023 Challenge. GeoCreate, the team from The 12

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University of Manchester, presented the most outstanding fully integrated evaluation and development plan, making them worthy of the Laurie Dake Challenge first prize. The team expressed their gratitude for being announced as the winners, and acknowledged the support provided by The University of Manchester, the EAGE Student Fund (which enabled their participation), and Professor Mads Huuse, who introduced them to the competition and EAGE. Composed of two geologists, two geophysicists, and one engineer, the GeoCreate team engaged in the three stages of the Laurie Dake Challenge from November 2022 to June 2023. Throughout the Challenge, they worked diligently, employing a range of technical analyses and integrated thinking to create a comprehensive development plan for a geothermal field in the Vienna Basin. The jury members, relying on their expertise and experience in geoscience and engineering, demonstrated a remarkable level of knowledge and meticulous attention to detail during the evaluation process. The extent of GeoCreate’s technical work, development planning, and integrated thinking left a lasting impression. Their work even impressed a group of attendees from OMV Exploration and Appraisal and the LCB Geothermal department who viewed the final presentations. The breadth of approaches and ideas showcased during the challenge highlighted the promising future of geoscience, engineering, and the energy industry as a whole. The winning team appreciated the jury’s valuable suggestions and observations, which fostered critical thinking, effective problem-solving, and elevated performance. As, for the first time, the Laurie Dake Challenge put the emphasis on geothermal energy exploration, the teams found it enlightening to understand how geoscience can contribute to the energy transition and prepare for future demands. They also applauded other related EAGE initiatives launched this year, such as the energy transition skills mapping, which enables geoscientists to attend relevant courses

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and bridge knowledge gaps in geothermal energy and CCUS, thereby enhancing their skill sets for the evolving energy landscape. The EAGE Student Fund offered financial assistance to the six finalist teams, covering the participants’ registration, travel, and accommodation costs. This enabled them to attend the conference in Vienna and opened the doors to meet professionals in the energy industry. The Challenge’s experience was completed with a dedicated student field trip to the OMV Innovation Centre. It was a standout highlight, offering educational and enjoyable simulations of various industry operations. Additionally, networking with like-minded peers from around the world provided invaluable opportunities for professional connections and the exchange of ideas.

Six finalist teams of the Laurie Dake Challenge 2023.

As we conclude this year’s remarkable journey, we extend an invitation to all aspiring students and young professionals to seize the opportunity and be part of the Laurie Dake Challenge 2024. This prestigious competition offers an unparalleled platform to showcase your skills, collaborate with fellow participants, and gain invaluable insights into the energy industry. Embrace the chance to tackle real-world challenges, harness your creativity, and contribute to the future of geoscience and engineering. The Laurie Dake Challenge awaits, ready to empower you with knowledge, experience, and the chance to leave a lasting impact. Join us on this extraordinary adventure, and together, let’s shape the future of the energy landscape. Stay tuned!

EAGE NEWS

Discover what awaits you at the IOR+ conference The technical programme for the 22nd European Symposium on Innovative and Optimised Resource Utilisation (IOR+) is now accessible online. The symposium is scheduled to take place from 2-4 October 2023, in the beautiful Dutch royal city of The Hague. This year’s technical programme promises to be exceptional, featuring (re)emerging applications like carbon capture (utilisation) and storage (CC(U)S), hydrogen storage, and geothermal energy. A series of extended keynotes will be delivered by global

experts on various topical themes. Presentations at the symposium will offer valuable updates and results from the latest research into IOR/EOR technologies. It will also showcase successful pilot projects and field-scale deployment of improved and enhanced oil recovery (EOR) methods. Emphasis will be placed on extending the reach of EOR while simultaneously reducing the carbon footprint of hydrocarbon recovery. Prepare to immerse yourself in an intellectually stimulating environment, where engineers, academics, scientists,

and students will present recent advances and brainstorm new ideas to improve resource utilisation in the future, while mitigating carbon emissions. Don’t miss this incredible opportunity to be part of shaping the future of energy innovation and sustainable resource management. Plan your visit to The Hague and register soon. The discounted rate for registration will be available until 10 September 2023. For more information about the Technical Programme and other event details, visit www.IOR2023.org.

Workshop to explore Eastern Mediterranean new energy potential Mark your calendars for the highly anticipated fourth edition of the EAGE Eastern Mediterranean Workshop, taking place on 4-6 December 2023. Following success in Cyprus, Athens, and Malta, this prestigious event returns to the Greek capital with the theme ‘Unlocking new energy resources’. The planned agenda to facilitate dialogue between experts, to inspire new ideas and creative thinking will help to unlock the potential of the East Mediterranean region’s petroleum systems. On this occasion, we eagerly invite submissions on the broad field of regional geology, hydrocarbon exploration and production, through the presentation of

Looking forward to next meeting.

case studies and related analogues. We are particularly interested in contributions evaluating and repurposing the region’s subsurface for alternative low-carbon uses, including carbon storage, hydrogen production and storage, geothermal energy, and wind power, aligning with

the energy transition objectives. While having a specific focus on the Eastern Mediterranean, submissions from outside the region that are analogues or impact the region are also welcomed. Seize this extraordinary opportunity to be part of an event that helps to shape the course of energy exploration and production in the Eastern Mediterranean region. Submit your two-page abstracts before 1 October 2023, and contribute to this exciting technical programme. Take advantage of the early bird registration rate, valid until 24 October 2023, and join us in the magnificent city of Athens.

EAGE Student Calendar 5 SEP

NEAR SURFACE GEOSCIENCE CONFERENCE & EXHIBITION 2023 (STUDENT ACTIVITIES) EDINBURGH, UK

5 SEP

STUDENTS E-SUMMIT: THE JOURNEY OF LOW CARBON TO NO CARBON: ROLE OF OIL & GAS EXPERTISE

ONLINE

6 SEP

MINUS CO2 CHALLENGE SECOND ROUND SUBMISSION

ONLINE

19 SEP

LATAM AND NORTH AMERICA EAGE STUDENT CHAPTERS MEETING

ONLINE

FOR MORE INFORMATION AND REGISTRATION PLEASE CHECK THE STUDENT SECTION AT WWW.EAGE.ORG.

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EAGE NEWS

Looking ahead to EAGE Digital 2024 Coming up on 25-27 March 2024 in Paris is one of the EAGE’s flagship events, the Fourth EAGE Digitalization Conference and Exhibition. Gautier Baudot, vice-president exploration excellence & transformation, TotalEnergies and chair of the event, explains the importance of the meeting. Our world is changing rapidly in many directions. Uncertainties are becoming the new norm. To keep up with this pace of change, we need to explore, find, and produce faster advantage barrels while also finding solutions for reaching net zero. This requires us to make the most of our data and use the best available technologies to unlock the right investment decisions faster. In geoscience projects, we need to invent new ways of working. This requires close collaboration with ‘new tech’ industries to reach our goals and fuel the energy transition. We are living in a time of great change in our industry and technology can help fill gaps created by emerging crises. The digital forum will be structured around three main axes:

1) New ways of working: making the most of our data with technologies – adapting our workflows and processes with digital tools to breach our silos to go faster; 2) Adapting our tools to the new tech world – embarking with the right technologies and shaping the new industry standards (OSDU, Cloud-based solutions, ML/AI, etc.); and 3) People: accompanying the people in this journey – form and train the workforce, attract young talents and prepare the new geodata scientists. The digital revolution is here, and our industry must seize it. We need to organise ourselves with new tools and workflows to deliver the energy the world needs. We look forward to welcoming you to Paris and let’s discuss and embark together on this journey under

Gautier Baudot, event chair.

the theme ‘Delivering better energy in a transforming world’. Keep an eye out for the latest news at www.eagedigital.org.

Positive and lively buzz surrounding EAGE Digital 2023 last March in London.

The EAGE Student Fund supports student activities that help students bridge the gap between university and professional environments. This is only possible with the support from the EAGE community. If you want to support the next generation of geoscientists and engineers, go to donate.eagestudentfund.org or simply scan the QR code. Many thanks for your donation in advance!

D O N AT E T O DAY ! 14

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PERSONAL RECORD INTERVIEW

Dr Robert Laws

Personal Record Interview

A life of floating ideas

At work and home Dr Robert Laws has never strayed far from the water in a life dedicated to marine sound acoustics and bioacoustics, not his first choice of career. Now a consultant, he retired after 25 years at Schlumberger’s Cambridge Research Centre contributing a number of important innovations.

Brought up on a boat When I was born, in 1954, my parents lived on at wooden coal barge that had been refitted for living. I lived there until I was two years old. Throughout my life I have felt a deep calmness by being on or near water and I think it stems from that early experience. Daydreamer at school I didn’t do awfully well at school. I was always daydreaming yet somehow managed to spot the answers to maths problems in a quirky way without ever learning the proper way to do them. I eventually had to choose between science and music, classical music was my other great love. I chose science. To everyone’s surprise, I was accepted for Oxford to read physics at St John’s. First shot at seismic method My first experience of a ‘shot-receiver pair’ was at the Royal Festival Hall, London. I had a holiday job as a technician measuring the reverberation time: the hall had an electronically modified acoustic called ‘Assisted Resonance’. It was my job to operate the sound source: it was a Colt 45 revolver! Landing your first job After university, I was invited to interview for a post with the Marconi Group which I had not applied for. The employers were very interested in my quirky way of solving problems and my daydreaming, but they could tell me absolutely nothing about what the job entailed. I had to make

my decision completely blind. I accepted, and to this day can’t say what it involved. Move to seismic business I wandered into the seismic world entirely by accident. Mainly for personal reasons, I wanted to live in Scandinavia, and heard that a company called Merlin was setting up a computer centre in Oslo. By a long chain of coincidences, I found myself kneeling on a floor in Woking surrounded by paper seismic sections with Les Hatton explaining seismic imaging and then offering me a job. I soon found myself as the sole software person at a small processing centre just west of Oslo. Les Hatton was one of the most influential people on my career. He taught me to welcome the unexpected, e.g., if your experiment gave the ’wrong answer’, great! It’s not a cause for gloom: it means you’ve learnt something new. Adding a PhD In due course I went to work directly for Les Hatton’s own company Programming Research with Gregg Parkes. I developed some software for modelling airgun bubbles, and was also taken on as a PhD student by Mike Worthington at Imperial College London. The software later became Gundalf, which is still widely used in the industry. Cambridge research years After something of a company merry-go round due to various industry consolidations, I found myself at Schlumberger Cambridge Research where I spent 25 years. I had a wonderful time there and FIRST

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was privileged to have many interesting and knowledgeable colleagues: Phil Christie, Ed Kragh, Ali Özbek, Håkon Aune, Jon Frerik Hopperstad, Everhard Muyzert, David Halliday, to name but a few. I worked on sound scattering by the moving rough sea surface (my fascination with the sea again) and then on what we should do to the airgun spectrum to minimise its impact on marine life; this work led to the spectrum design requirements for the E-source airgun. Then I worked on the marine vibrator, in particular the exploitation of the control of phase that it allows. I was able to show how phase sequencing, changing the phase from one shot to the next in a special sequence, could enable the removal of the residual shot noise. This has major benefits for efficiency. Post-retirement consultancy I lost my job at Schlumberger in 2018 when the company sold its marine seismic acquisition business. Luckily for me, this was acquired by Shearwater which has continued the development of the marine vibrator. I consult through my company Havakustik and also work with various organisations dealing with the measurement and effects of sound sources in the ocean. Back on a boat As previously mentioned, boats have been part of my life from birth. I lived on a boat on the river Cam in Cambridge for many years. In fact, I am answering these questions remotely from my current boat in the middle of the Fens of East Anglia. I

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29 September 2023 Call for Abstracts EAGE/AAPG Workshop on New Discoveries in Mature Basins 1 October 2023 Call for Abstracts Fourth EAGE Eastern Mediterranean Workshop 1 October 2023 Early Registration Fifth EAGE Conference on Petroleum Geostatistics 13 October 2023 Regular Registration Third EAGE Workshop on Mineral Exploration in Latin America 13 October 2023 Regular Registration Second EAGE Workshop on Geothermal Energy in Latin America

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CROSSTALK BY AN D R E W M c BAR N E T

•

Land seismic back in the frame It seems paradoxical that in the past two decades so much creative essentially became so disillusioned that five years or so ago they energy has gone into the evolution of land seismic data acquisition voluntarily sold off their marine seismic fleets, thereby adding technology with such modest reward to show for it. In other words, to the list of many illustrious names that were forced to quit the the market has remained stubbornly inert outside the deserts of the business or vanish in some defensive merger. Middle East and North Africa. The question is whether the recent Market disruption in such a niche market as land and marine emergence of absurdly inexpensive, easy to deploy, recording seismic does not guarantee a viable business. An article in First nodes and their possible applications for the energy transition Break (Vol 21, February 2003) by well-known BP geophysicist agenda can shift the needle. Ian Jack entitled ‘Land seismic technology: Where do we go from The modern technology story really begins around the turn here?’ provides a reminder of how things were 20 years ago noting of the century when the cost and efficiency of land seismic cable that the industry continues ‘to drape geophones, cables and instrusystems came under fresh scrutiny. This was era of major oil ments all over the countryside at a huge combined cost of access, consolidations when ExxonMobil was created, Chevron swallowed deployment, capital, depreciation, and retrieval. Our instrument up Texaco, BP took over Amoco and Total channel count may be rising but the cost per merged with Elf Aquitaine. Oil companies were ‘Market disruption … channel, although reducing slowly, remains cost-conscious as never before. in the $1000 region. The weight per channel does not guarantee is also reducing, slowly, but the total weight As a result, the onus weighed more heavily than ever on the service companies to do the and cost of deployed equipment is probably a viable business’ research and come up with cost-effective solurising due to the extra channel count. On many tions. Today some impressive advances both in onshore seismic of our operations, 10-20 tonnes of recording equipment have source and receiver technology have been made but the number of to be moved daily – expensive in terms of vehicles, manpower players providing services and equipment has diminished signifand often helicopters. Radio systems are of course available, but icantly. Both these industry sectors have of course been battered tend to be used in “last resort” situations, presumably because of by the volatile demand pattern, particularly the major low in 2008 overall cost.’ and then the prolonged 2014 downturn when cyclical recovery was Back then, Jack speculated about what needed to change. The stalled by the global pandemic in 2019. geophone together with its casing and wiring was an intrinsically There are obvious parallels with marine seismic developments heavy and expensive unit, and as such a candidate for replacement, over much the same period. There, leading companies presumed for example, by micro-machined sensor systems then under that technology differentiation would pave the way to commercial development. This opened the possibility of production in an success. But advances such as 3D seismic and 4D reservoir moniextremely lightweight version that could be cheap in a high-volume toring, bigger seismic towed streamer counts, broadband, onboard production environment. It was clear that the pressures to improve processing, to name but a few, may have given one contractor or sampling and to achieve single sensor recording would ‘drive other a brief moment in the sun. Soon however, the competition us to channel counts far in excess of what we use today, even in caught up effectively diluting any premium a company’s innovasingle-component model … Low deployed weight, simplicity of tion may have earned. Also, industry clients could often opt for a equipment, and removal of the need for extensive cabling would be basic 3D acquisition package eschewing the more sophisticated attractive features in a new high-channel-count system.’ offerings so expensively researched and developed. Symptomatic Now in 2023 we can see that much of Jack’s technology vision of this disarray, two leading contractors Schlumberger and CGG has been addressed. Sercel’s 508XT and Inova’s G3iNXT provide

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CROSSTALK

initially a joint venture with the now dissolved ION Geophysical. state-of-the-art lightweight real time recording cable systems Parent support and persistence enabled its node products to evolve including built-in redundancy and highly developed vibroseis and outlast just about all the often under-funded competition, capable of undertaking mega crew surveys. Just as an example, Sercel being the exception. Inova Geophysical, in collaboration with BGP, boasted in 2018 a There is no space here to mention the many hopefuls launched successful mega channel, broadband, high density, digital single along the way since Fairfield’s now primitive land/marine Box sensor acquisition system for Kuwait Oil Company (KOC). The node was launched in 1998. Opseis Eagle and I/O RSR were other company’s G3i HD system operated with 238,000 digital channels early contenders. At that time developments were a largely North and involved several fleets of 80,000 lbs AHV-IV 380 Renegade American phenomenon with the emphasis on flexibility to go vibrators, delivering high energy, low frequency signal in a broadwhere cable could not, i.e., across roads, rivers, no permit zones, band sweep configuration. congested areas, and environmentally sensitive areas. Higher Commercial acceptance of these competing solutions suggests productivity with no downtime for cable repairs, and reduced crew that cable systems will continue to have a place in certain environand transportation costs were also important benefits. ments, regardless of any logistical, HSE or cost criticism thrown There followed a long period of uncertainty where the direction at them. Indeed customers in Kuwait and Saudi Arabia have not of the technology was unclear as comshown themselves to be totally convinced of the merits of node deployment. A likely ‘Contractor withdrawals left panies wrestled with the option of ‘blind shooting’, some form of continuous QC or future outcome will see instances where the door open to BGP’ real time data as per the Wireless Seismic land seismic surveys combine the two techRT System 2. These days, blind has won nologies to meet the terrain to be covered. the argument proving to be the most practical, productive and Improvements in cable over time were able to build on well-esextremely reliable (settling an early worry for potential customers). tablished technology with the expectation of adoption by existing The arrival of the Solo Smart super-cheap node (manufactured users. This was not the case for the pioneering of node-based land by Chinese company DTCC but marketed from Calgary) can be seismic. A business case had to be made with proof of concept to credited with pointing the nodal market in the direction of high create the market, a process that hampered progress. density, low cost and safe acquisition. The company retains a The timing was not good either. By 2000 global onshore share of the Chinese and global business but is dwarfed by the seismic prospects were becoming scarcer, at least for the major head-to-head competition between Inova’s Quantum lightweight oil companies. There were fewer prospects of sufficient scale node and the Nimble system from UK-based STRYDE, the bp around the world, the potential survey areas could be challenging subsidiary that burst onto the scene three years ago. This is not (jungles, mountains, etc), and permitting in some jurisdictions to overlook Sercel’s Wing, a more sophisticated node deployed could be burdensome. Most obviously, offshore acreage in numerfor high-quality data incorporating the company’s QuietSeis ous countries was much easier to access. 3D marine seismic had ultrasensitive digital MEMS sensor, evolved from Vibtech’s Unite become extremely cost-effective and promised almost unlimited system acquired in 2006. opportunity for proprietary and multi-client surveys. Based on several years’ research in bp, STRYDE provides This combination of circumstances gradually took its toll a low-cost method to achieve acceptable high-density seismic on international land seismic contractors with players such as based on fast, mass deployment of miniature nodes, 90 of which Schlumberger, CGG and PGS all eventually pulling out of active can be carried by one individual in the field, accompanied by an operations. Geokinetics went out of business in 2018 with its assets assistant for set-up and positioning. The numbers claimed for nodes acquired by SAExploration, and in the US, the remaining company produced, approaching one million according to the company, and of any importance, Dawson Geophysical, has effectively been resdeployment in over 40 countries, make impressive publicity. cued by an investment company. Occasional multi-client projects Leaving aside the hype, the real significance of STRYDE lies in North America continue to be developed by among others, TGS. in the company’s ambition to move beyond oil and gas related The contractor withdrawals left the door open to BGP to expand seismic. The company this year has already announced 10 new from its home market to supply land seismic overseas, beginning contracts for geothermal projects in the US, Middle East and in the 1990s. It rapidly became by far the largest contractor in Europe. It intends also to continue pursuing project opportunities the world. By 2014, the company had 65 land crews, employed in CCS, mining, agriculture and archaeology. How far this diver20,000 people, worked for numerous clients including NOCs and sification can sustain the company’s production line remains to supermajors in over 50 countries and built 70% of its business be seen. If history is any guide, there will be competition. CGG’s outside China, according to vice-president Zheng Huasheng in an Beyond the Core initiative already takes Sercel into non-traditional interview with GeoExpro. fields such as structural monitoring. BGP’s dominance of the land seismic survey market was What is encouraging is that land seismic data acquisition reinforced by its early entry into the emerging node technology technology can be made relevant outside the oil and gas arena. through INOVA, its land seismic equipment manufacturing arm, Views expressed in Crosstalk are solely those of the author, who can be contacted at andrew@andrewmcbarnet.com.

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www.smartsolo.com

Email: sales@smartsolo.com

HIGHLIGHTS

INDUSTRY NEWS

Shearwater shoots node survey for OMV

TGS shoots 3D survey offshore Australia

PGS processes Côte D’Ivoire data

UK reveals plans to issue hundreds of new oil and gas licences in the North Sea Hundreds of new oil and gas licences will be granted in the UK after the country’s prime minister Rishi Sunak committed to future licensing rounds. Pointing to new analysis showing domestic gas production has a quarter of the carbon footprint of imported liquified natural gas, Sunak confirmed that the UK will continue to back the North Sea oil and gas industry as part of plans to make the country more energy independent. By adopting a more flexible application process, licences could also be offered nearer to currently licensed areas – unlocking vital reserves which can be brought online faster due to existing infrastructure and previous relevant assessments. With the UK’s Climate Change Committee predicting around a quarter of the UK’s energy demand will still be met by oil and gas when the UK reaches net zero in 2050, Sunak said he is taking steps to slow the rapid decline in domestic production of oil and gas. The UK North Sea Transition Authority – responsible for regulating the oil, gas and carbon storage industries – is currently running the 33rd offshore oil and gas licensing round. It expects the first of the new licences to be awarded in the autumn, with the round expected to award more than 100 licences. As the UK is a rapidly declining producer of oil and gas, new oil and gas licences will offset the fall in UK supply in

order to ensure vital energy security, rather than increase it above current levels, so that the UK remains on track to meet net zero by 2050, said the UK government in a statement. Sunak said: ‘We have all witnessed how Putin has manipulated and weaponised energy – disrupting supply and stalling growth in countries around the world. ‘Now more than ever, it’s vital that we bolster our energy security and capitalise on that independence to deliver more affordable, clean energy. ‘Even when we’ve reached net zero in 2050, a quarter of our energy needs will come from oil and gas. But there are those who would rather that it come from hostile states than from the supplies we have here at home. ‘We’re choosing to power up Britain from Britain and invest in crucial industries such as carbon capture and storage, rather than depend on more carbon intensive gas imports from overseas.’ David Whitehouse, CEO Offshore Energies UK said: ‘There are currently 283 active oil and gas fields in the North Sea, by 2030 around 180 of those will have ceased production due to natural decline. If we do not replace maturing oil and gas fields with new ones, the rate of production will decline much faster than we can replace them with low carbon alternatives. FIRST

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‘Developing our new carbon capture industry and its high-value jobs needs significant investment from our energy producing companies.’ Russell Borthwick, chief executive of Aberdeen and Grampian Chamber of Commerce, said: ‘In the midst of a hugely polarised debate around energy – with

much of the commentary characterising it as a battle of good versus evil (which it is not) – the UK must produce as much of our required supply as possible here, with full control over the regulatory environment in which it is extracted. ‘The alternative is that we import an increasing amount of our energy, with the heavier carbon toll and supply risks that shipping it from other parts of the world carries. The latter option makes little economic sense, and even less environmental sense.’ I

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INDUSTRY NEWS

UK study pinpoints North Sea areas for carbon capture, utilisation and storage University of Aberdeen has identified areas of a North Sea gas ‘super basin’ with the greatest potential for storing industrial carbon emissions. Scientists from the University’s Centre for Energy Transition used subsurface data and techniques usually employed in oil and gas exploration, to produce a detailed technical study of the Anglo-Polish Super Basin in the Southern North Sea to confirm its suitability for carbon capture, utilisation and storage (CCUS) in former gasfields and other geological formations. As well as showing the geological criteria that determine the areas with the greatest potential, the study also assesses non-geological risks – such as the potential for leaks along legacy wells and potential conflicts with other stakeholders such as windfarm operators or the fishing industry. The two-year study funded by the UK-based Net Zero Technology Centre was led by Professor John Underhill, director of the University’s Centre for

Emissions from heavy industry will be stored.

Energy Transition, along with colleagues from Heriot Watt University in Edinburgh. Professor Underhill said that the study could provide a basis for other studies of potential CCUS sites around the world: ‘The study highlights the areas where the best carbon stores are located and provides a basis to evaluate and rank sites. ‘Perhaps just as importantly, it also demonstrates the urgent need for regulators and stakeholders to work together to resolve any issues that may arise from the co-location and overlap of technologies to avoid competition for the offshore real estate. This is vital in ensuring that the UK remains on track to retain energy security and meet its net zero emission targets.

‘The study also has global relevance and application, and the workflow we have used has already been adopted by other countries. We have also used it to undertake studies in other parts of the UK as well as in Malaysia, Egypt and Brazil.’ Dr Nick Richardson, head of exploration and new ventures at the UK North Sea Transition Authority, said: ‘The Aberdeen University-led team has made a timely and incisive contribution with this worldclass research that puts the UK’s storage resource capability on the map as a leading destination for the sequestration of industrial emissions from across Europe. ‘By establishing a consistent regional geological framework, this work will assist the evaluation of storage sites within the Southern North Sea, allowing the optimisation of their exploitation and supporting assessments of risk and uncertainty. It will also aid regulatory and marine planning bodies in their ongoing efforts to identify synergies between offshore activities, and maximise opportunities for innovation and collaboration on the pathway to net zero.’

CGG, PGS and TGS upgrade their joint multi-client data system CGG, PGS and TGS have launched new tiered offerings for the joint venture’s Versal multi-client data repository. The update gives the industry free access to Versal, which the partners claim represents ‘the world’s most comprehensive multi-client data coverage in one centralised location’. ‘Industry professionals can also benefit from a more personalised solution, with a focus on enhanced accessibility, flexibility and value,’ said the Versal partners in a statement. ‘Updates to the Versal platform are designed to offer more convenience and scalability for exploration and production, data management and procurement team members.’ 22

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Versal users are given unlimited access to essential data from CGG, PGS and TGS, representing the majority of the world’s marine multi-client data available within a single platform. This consolidation eliminates the need to visit multiple vendor websites, streamlining workflows and saving valuable time. With the free Versal version, users can view data coverage, download coverage shapefiles and import their map layers and shapefiles. By upgrading to Versal Pro, clients unlock additional benefits, including viewing entitlements, accessing vendor contracts, and downloading acquisition and processing documents. Versal Premium users gain access to enhanced

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data management capabilities such as seismic visualisation and downloading entitled traces, said the joint venture. Dechun Lin, EVP, Earth Data, CGG, said: ‘By providing access to the world’s first and only multi-client data ecosystem, we are empowering exploration and production, data management and procurement professionals to increase their efficiency and unlock the full potential of their projects. Versal’s tiered offerings ensure that users can tailor their experience to their specific needs, while the comprehensive data coverage from the industry’s leading providers gives them a competitive edge in their decision-making process.’

INDUSTRY NEWS

Current investment levels are enough to meet global demand for oil and gas in the 2030s, says Wood Mackenzie Peak oil and gas demand can be met in the 2030s without a substantial increase to current annual investment levels of $500 billion in 2023 terms, according to Wood Mackenzie. Current upstream spending is a little more than half of the $914 billion 2014 peak (in 2023 terms), according to its report Enough is Enough Debunking the Myth of Upstream Investment. This apparent shortfall has fed a widespread belief that the industry is underinvesting and that a supply crunch is inevitable. Fraser McKay, Head of Upstream Analysis for Wood Mackenzie, said: ‘Our long-held view has been that spending and supply would rise to meet recovering demand and that the upstream industry would not and could not reprise the ignominious years of ‘peak inefficiency’ during the early 2010s.’ Wood Mackenzie predicts that oil demand will eclipse pre-pandemic highs in 2023, but from 2024 will slow, reaching a peak of 108 million barrels per day (b/d) in the early 2030s.

Spend levels not much higher than the current run-rate can deliver the supply needed to meet demand through to its peak and beyond owing to the development of giant low-cost oil resources, capital discipline and improvements in investment efficiency, the company added. As a result investment required in 2033 will be $613 billion with just 2% macro inflation. The price shocks of 2015-2016 and 2020-2021 have forced the industry to become far more disciplined with its capital, said McKay. ‘Conventional greenfield unit development costs have been slashed by 60% in 2023 terms and US tight oil wells generate nearly three times more production today for the same unit of capital than in 2014. New technology, capital efficiency and modularisation have been leveraged to powerful effect.’ Most of the industry’s oil and gas investment for the rest of this decade will target advantaged resources: those with the lowest cost, lowest emissions and least risk.

Unlock Subsurface Potential in the Norwegian North Sea Discover the full exploration potential of open acreage offshore Norway with multi-client Ocean Bottom Node data for the ultimate subsurface image.

Shearwater shoots streamer and node survey for OMV Shearwater is conducting a pioneering towed-streamer ocean bottom node survey for OMV over the Berling gas and condensate discovery in the Norwegian Sea.

Oceanic Vega.

Spanning 1040 km2, the three-month hybrid survey due to complete in October, uses Shearwater’s advanced vessels, SW Tasman and Oceanic Vega. SW Tasman will operate as an ROV node deployment vessel for the first time, after its conversion announced on 22 October 2022 and will deploy the nodes before Oceanic Vega acquires the multi-Azimuth towed streamer survey. ‘By completing the conversion of SW Tasman, Shearwater has adapted our fleet to control more operational factors inhouse as we meet the increased demand in the seabed market,’ said Irene Waage Basili, CEO of Shearwater. FIRST

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INDUSTRY NEWS

ENERGY TRANSITION BRIEFS TotalEnergies, Baker Hughes, Technip Energies, Azimut and other investors have signed an agreement to invest in Zhero Europe to develop large-scale wind and solar energy projects in Europe and Africa spanning across power generation, power interconnections and green molecules. ExxonMobil has acquired Denbury, a developer of carbon capture, utilisation and storage solutions and enhanced oil recovery for $4.9 billion. Aker Carbon Capture and Aramco have formed a partnership to explore opportunities to deploy carbon capture, utilisation and storage and industrial modularisation in Saudi Arabia. Equinor has signed an agreement with Denham Capital to acquire Rio Energy, a leading onshore renewables company in Brazil. The transaction includes selected assets and the team, while Denham Capital will retain certain assets. ‘Brazil is the largest power market in South America, with expected demand growth and fast expansion of the deregulated market,’ said Equinor. bp has been awarded the rights to develop two offshore wind projects in the German tender round, marking its entry into offshore wind in Continental Europe. The two North Sea sites, located 130 km and 150 km offshore in water depths of about 40 m, have a total potential generating capacity of 4GW. Bp will lead the development, construction and operations of these fixed-bottom offshore wind projects, with grid connection targeted by end 2030. Vår Energi has acquired Feistein CCS, a company, a company specialising in maturing large-scale CO2 storage opportunities. TotalEnergies has won leases to develop windfarms offshore Germany. N-12.1 covers 200 km2 in the North Sea some 170 km from the coast. 0-2.2 covers 100 km2 in the Baltic Sea and is 40 km off the coast.

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UK confirms two more carbon usage and storage clusters The UK has confirmed that the Acorn project in north eeast Scotland and the Viking project in the Humber (off the north east coast) have been chosen as the third and fourth carbon capture usage and storage clusters in the UK. The UK government has already committed to deploying CCUS in two industrial clusters by the mid-2020s – the HyNet cluster in north west England and North Wales, and the East Coast Cluster in the Teesside and Humber – and the next two clusters are expected to be operational by 2030. ‘The UK has one of the largest potential carbon dioxide storage capacities in Europe, making the North Sea one of the most attractive business environments for CCUS technology. The government has committed to providing up to £20 billion in funding for early deployment of CCUS, unlocking private investment and

job creation,’ said the UK government in a statement. Ruth Herbert, chief executive at the Carbon Capture and Storage Association, said: ‘We are pleased to see the UK government selecting the next two CCUS clusters, as time is running out to meet 2030 targets. ‘It is therefore vital that the government urgently sets out clarity on the process and timeline for selecting carbon capture sites within these ‘Track-2’ clusters and within the previously announced Track-1 cluster expansion. Billions of pounds of investment is waiting to be deployed to decarbonise these industrial regions, but firm plans are required to secure it. ‘There are a number of other clusters under development across the country, which is why last year we asked government for visibility of the longer-term CCUS deployment plan.’

Buru shoots a 3D seismic survey in Western Australia Terrex Seismic is shooting a 3D seismic survey for Buru Energy within exploration permit EP 428, including Buru’s owned and operated Rafael conventional gas and condensate discovery. The 200 km2 land survey area will also extend into exploration permit EP 457 (Buru 60% and operator, Rey Oil and Gas Pty Ltd, 40%) and will include four 2D seismic lines wholly within EP 457 which will provide data to inform prospect maturation which could provide future backfill opportunities for the Rafael development. Buru’s CEO Thomas Nador said of the decision to appoint Terrex to undertake the seismic acquisition: ‘Terrex is a company with a strong track record of seismic operations in Australia, experience in the Canning Basin and experience with Buru on previous survey campaigns. SEPTEMBER

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Acquiring 3D seismic data over the Rafael structure is the highest impact, highest value, and most cost-effective activity we can do today to derisk the subsurface, inform our 2024 appraisal drilling program, underpin our ongoing project development work, and create new partnership opportunities for the Rafael development.’ The seismic survey is expected to take eight weeks. Contracts have also been entered into for data processing, including a fast-track volume by Q4 2023 and initial interpretation by the end of the year to aid planning and approvals for appraisal well drilling in the second half of 2024. A second and parallel phase of processing will use more sophisticated and time intensive techniques to extract finer details and geophysical attributes from the data, said Buru.

INDUSTRY NEWS

CGG reports second quarter net profit of $39 million CGG has reported a second quarter group net profit of $39 million on revenues of $339 million compared with a net profit of $16 million on operating revenues of $228 million in Q2 2022. Operating profits were $82 million compared with $59 million in Q2 2022. Segment revenue of $289 million compared with $240 million in Q2 2022. Digtial, Data and Energy Transition (DDE) revenue was $142 million, down from $195 million in the second quarter of 2022. Geoscience revenue of $80 million was up 14% year on year as a result of ‘sustained demand for OBN imaging’. Backlog is up 19% to $235 million. Earth Data revenue was $62 million, down 5% year on year. Prefunding revenue was $42 million, up 17% and prefunding rate was 66%. After sales were ‘low’ at $20 million. Sensing and Monitoring Revenue was $146 million, up 222% year on year thanks to the high level of land equipment sales in North Africa and the Middle East

totalling $46 million. Marine equipment sales of $84 million were boosted by sales of GPR ocean bottom nodes. Sophie Zurquiyah, CGG CEO, said: ‘Our Geoscience business is back to pre-Covid levels, driven by technology differentiation and the increasing adoption of advanced acquisition technologies, such as nodes. Earth Data remains in line with our full-year objectives while Sensing and Monitoring confirmed its expected rebound, with high quarterly revenue. ‘Increased SMO activity in Q2 drove working capital higher, which is expected to translate into significant positive cashflow in H2. The market remains active, with clients strengthening their offshore activity worldwide. This together with our $510m backlog, which is at the highest level since early 2020, gives us confidence in delivering our 2023 targets.’ The IEA said that since the last updates to the IEA’s Tracking Clean

Energy Progress and Clean Energy Technology Guide, the world’s largest battery manufacturer announced it would begin production of sodium-ion electric vehicles batteries, an alternative battery chemistry that can help to reduce reliance on critical minerals. Two large-scale demonstrations of solid oxide electrolysers, a highly efficient technology for producing low-emission hydrogen, started operating earlier this year. There have been positive steps in innovative clean technologies for aluminium refining and cement-making. Furthermore, in early 2023, the first shipment of liquid carbon dioxide (CO2) was taken from Belgium to be geologically stored off the coast of Denmark beneath the North Sea. However, the IEA warned: ‘Stronger policy support and greater investment are needed across a wide range of different technologies, in all regions of the world, to enable a broader and faster shift towards clean energy to keep net zero emissions by 2050 within reach.’

TGS launches 3D survey offshore south Australia

Acquisition covers 45,000 m2.

TGS has launched a 3D multi-client marine seismic survey in the Otway Basin in Commonwealth waters offshore from Victoria, and Tasmania, south east Australia. The survey will

provide 3D data coverage and improved subsurface imaging to improve understanding of the subsurface, which has been limited to sparse 2D coverage. The survey area is ~38 km from land at the closest point. Discrete surveys will be acquired within the acquisition area, which covers ~45,000 km2. Water depths within the AA range from 115 m to 5650 m. The project will also include a ‘tiein’ to existing geophysical data from previously drilled wells. The 2D tie-line will overlap with 3D data acquisition in the AA. However, it will also extend onto the Continental Shelf and represents a few hours of active source time in shallower waters. At the shallowest point, the tie-line is in a water depth of approximately 115 m and additional FIRST

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control measures will be implemented for this. A single seismic vessel will tow up to 14 seismic streamers 8-10 km long. The seismic vessel will travel at ~4.5 knots. The acoustic source will either be a ‘dual source’ (comprising two source arrays discharged alternately) or a ‘triple source’ (comprising three source arrays discharged alternately). Each acoustic array will have an effective volume of up to 3480 in3. The survey is expected to start in October (pending regulatory approval) and will be completed by 30 September 2027. Maximum acquisition time during any calendar year is 200 days with a maximum of 400 days. Based on an analysis of weather and sea state, acquisition is likely to occur from October to March. I

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INDUSTRY NEWS

PGS processes 3D data offshore Côte D’Ivoire

KPSTM imaging was used.

PGS has processed more than 2000 km2 of new broadband 3D seismic data for offshore Côte d’Ivoire, using the latest KPSTM technique to image prolific Cretaceous reservoir targets. Several high-profile discoveries have been made in and around the shelf edge in recent years. The drilling of the Afina1 well (Springfield, 2019) in Ghana and the discovery and subsequent expansion of the Baleine structure (Eni, 2021/2022) have shown that there are significant vol-

umes of hydrocarbons being found in the Cretaceous over continental crust across this well-explored basin, said PGS. Two main plays have been the focus for exploration in the Tano Basin: the syn-transform Lower Cretaceous and the post-transform Upper Cretaceous. The Lower Cretaceous play dominates the area around the shelf edge in both the Ghanian and Ivorian offshore. A contributing factor in this inboard dominance is the source-rock maturation history. Berriasian to Albian source rocks sit within the gas maturity window around the shelf due to a relatively thinner overburden, whereas they are likely to be over-mature in more distal syn-transform basins where the depth of burial is greater. These source rocks are paired with Albian-aged fluvial to shallow marine syn-transform sandstones, as proven in the Baobab Field. The Upper Cretaceous system is most successful around and outboard of the

present-day shelf edge due to the thick clastic section allowing for sufficient burial of shallower Ceromanian-Turonian-aged source rocks. These type II source rocks have been proven to have mixed oil and gas potential. Complementing this widespread source kitchen are Albian-to-Santonian-aged shallow to deep marine sandstone reservoirs. The largest discovery in this play is contained within the Baleine shelf-edge structure, which is reported by Eni to contain 2.5 billion barrels of oil and 3.3 trillion cubic feet (TCF) of associated gas over two main reservoir levels. This discovery has also expanded the Upper Cretaceous play to include carbonate shelf edge reservoirs. GeoStreamer technology was applied in this 2023 acquisition and has been paired with modern broadband processing. This AVO-compliant pre-stack data will also help to reveal subtle depositional features, significantly de-risking exploration, said PGS.

Progress on clean energy technologies is better than expected, says IEA The clean energy energy economy is taking shape as a result of the rapid development of technology, said the International Energy Agency (IEA). The IEA’s Tracking Clean Energy Progress report shows that electric car sales reached a record high of more than 10 million in 2022, a nearly tenfold increase in five years. Renewable electricity capacity additions rose to 340 gigawatts (GW), their largest ever deployment. As a result, renewables now account for 30% of global electricity generation. Investment in clean energy reached a record $1.6 trillion in 2022, an increase of almost 15% from 2021. Costs have fallen and technologies are relatively mature in clean electricity generation, but rapid innovation is still needed to bring to market clean technologies for parts of the energy system where emissions are harder to tackle, such as heavy industry and long-distance transport. 26

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The IEA has also released the Clean Energy Technology Guide, an interactive digital database of more than 500 innovative technologies across the global energy system, along with the accompanying Clean Energy Demonstration Projects Database. ‘The clean energy economy is rapidly taking shape, but even faster progress is needed in most areas to meet international energy and climate goals,’ said IEA executive director Fatih Birol. ‘This update of Tracking Clean Energy Progress highlights some very promising developments, underlining both the need and the potential for greater action globally. The extraordinary growth of key technologies like solar and electric cars shows what is possible.’ For the first time, announced manufacturing capacity for electric vehicle batteries has reached levels sufficient to fulfil expected demand requirements in 2030 in the IEA’s scenario for achieving net zero emissions by 2050.

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Solar PV has been upgraded to ‘on track’, as its progress now aligns with milestones consistent with net zero ambitions. Solar PV generated a record of nearly 1300 terawatt-hours (TWh) in 2022, up 26% from 2021 and logging the largest absolute generation growth of all renewable technologies in 2022. The number of manufacturing projects in the pipeline for solar PV also had massive growth in the context of widespread government support, especially in China, the US and India. If all announced projects are realised, global manufacturing capacity for solar PV will more than double in the next five years, outpacing 2030 demand in the IEA’s Net Zero by 2050 Scenario. Policy is advancing in many regions. Earlier this year, for example, Indonesia became the first country in Southeast Asia to establish a legal and regulatory framework for carbon capture, utilisation and storage.

INDUSTRY NEWS

US launches first Gulf of Mexico offshore wind lease sale The US Department of the Interior will hold the first-ever offshore wind energy lease sale in the Gulf of Mexico to deploying 30 gigawatts (GW) of offshore wind energy by 2030 and reach a carbon-free electricity sector by 2035. The Final Sale Notice (FSN) includes a 102,480-acre area offshore Lake Charles, Louisiana, and two areas offshore Galveston, Texas, one comprising 102,480 acres and the other 96,786 acres. The FSN provides detailed information about the final lease areas, lease provisions and conditions, and auction details. It also identifies qualified companies who can participate in the lease auction.

wildcattechnologies.com +1 (281) 540-3208

BOEM expects to review at least 16 Construction and Operations Plans of commercial, offshore wind energy facilities by 2025, which would represent more than 27 GW of clean energy for the nation. The areas, which were set to be auctioned on 29 August by the Bureau of Ocean Energy Management have the potential to generate approx. 3.7 GW and power almost 1.3 million homes.

Seabird wins big OBN contract in Western Hemishphere

SeaBird has won a two-year contract for OBN source services in the Western Hemisphere spanning several projects. The contract is for a repeat tier 1 client and the Fulmar Explorer was expected to mobilise this month with day rates ‘reflective of an improving OBN market’. The contract was expected to start this month ‘in direct continuation of the current contract’. FIRST

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‘It is a game changer for the company as it provides a cashflow visibility that is unusual in our industry,’ said Ståle Rodahl, executive chairman. ‘The contracted day-rates are reflective of an improving OBN market. With this contract, we are particularly pleased to report a total EBITDA backlog now in the vicinity of the company’s current market capitalisation.’ I

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HAWK Pyrolysis & TOC Instrument HAWK-PAM Petroleum Assessment

INDUSTRY NEWS

PGS completes first offshore windfarm characterisation

PGS has completed its first ultra-high-resolution 3D characterisation for the Morgan and Mona offshore wind farms in the Irish Sea for clients bp and EnBW. Subsurface data was acquired using PGS’ ultra-high-resolution 3D (UHR3D) P-cable system which the company claims provides significantly more detailed subsurface data for shallow targets, compared to traditional seismic acquisition systems. ‘Our UHR3D system acquires near-surface data significantly more efficiently than conventional solutions and builds on our geophysical expertise and vessel opera-

tion experience. By meeting our client’s objectives in our first ultra-high-resolution windfarm site characterisation project, I am increasingly confident that our geophysical approach to understanding the shallow subsurface layers has a proven market fit. Our business is ready to be scaled further to increase our market share in offshore wind site characterisation,’ said Berit Osnes, executive vice-president New Energy at PGS. Meanwhile, PGS has secured a $75 million loan to partly refinance its $138 million term loan B to be repaid in March 2024. Interest rate of the new term loan is in line with the existing loan (SOFR + 7%, compared to LIBOR + 7% currently). The new loan will share the same security as the company’s $450 million bonds. It will be drawn in Q3 2023 with net proceeds used for debt repayment. Lenders are Sculptor Capital Management and Värde Partners.

Final maturity of the loan will be 15 December, 2026.

Fugro seabed studies Fugro is performing offshore geophysical studies for the UK Crown Estate in the Celtic Sea off the coast of Wales and South West England to analyse plans for offshore wind farms. The 100-day project will use towed and hull-mounted sensors to gather geophysical data on the properties of the seabed and sub-seabed. The multi-million-pound programme includes plans for further surveys over the next two years to collect data on everything from wind and wave patterns to birds and marine mammals in the area. Datasets will be made freely available to successful bidders. Four project sites are set to deliver up to 4GW of floating wind capacity.

TGS launches 3D survey offshore Nigeria TGS and its partner Petrodata have launched the Awele South 3D multi-client survey offshore Nigeria. The project, which aims to provide insights into deep and ultra-deepwater petroleum systems of the Niger Delta Basin, will encompass approx. 5900 km2 within the designated 56,000 km2 PEL area. Will Ashby, executive vice-president for the Eastern Hemisphere at TGS, said,

‘TGS-Petrodata has an extensive multi-client data library in Nigeria, including reprocessed 2D seismic and our regional multibeam and seafloor sampling study. Having insight into the petroleum system of the Niger Delta basin will enhance our understanding of the country’s potential energy resources.’ The project will span w90 days, with completion planned in Q4.

Meanwhile, TGS has completed a key ocean bottom node (OBN) project in the North Sea and started its next project in the same area. The projects are being executed using the TGS Z700 OBN crew. The crew has completed two projects during the North Sea season and is currently working on two more as TGS increases its presence in the sector.

RPS shoots environmental survey for Australian wind energy project RPS has launched a marine environmental survey programme for Flotation Energy’s Seadragon wind project offshore Gippsland, southeastern Australia. Anna Crameri, RPS’ offshore wind development lead, said the $22 million programme will play a critical role in the development over several years. ‘Our marine baseline program for Flotation Ener28

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gy will inform the environmental impact assessment (EIA), which is a requirement for developers seeking project approval. The programme findings will also play an important role in design and mitigation measures to minimise the impact of development on the environment.’ The first marine field survey started in July and deployed acoustic moni-

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toring equipment to help understand how marine mammals such as whales and dolphins use the proposed project area.’ RPS will shoot the surveys in collaboration with JASCO Applied Sciences, Deakin University and Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO).

TECHNICAL ARTICLE

Multi-scenario deep learning 4D Inversion: A Brazil pre-salt case study Yang Xue1, Dan Clarke2* and Kanglin Wang1.

Abstract After successful derisking of the technique, time-lapse (4D) seismic is now being deployed across the Santos Basin pre-salt as a tool to enhance oil recovery and assist with reservoir management. Two main shortcomings of conventional 4D interpretation approaches for pre-salt reservoirs are the limited vertical resolution (especially given the heterogeneity of the reservoir) and the inadequate uncertainty handling (anchoring to a single solution in a low-signalto-noise ratio environment). To address those challenges, we developed a multi-scenario deep learning (DL) workflow for high resolution 4D inversion. Several training datasets were constructed from multiple scenarios to cover reasonable uncertainty ranges. Each scenario was trained separately with a Convolutional Neuron Network (CNN). The trained models can then be applied to the real 4D seismic data to generate a set of predicted reservoir property change volumes in almost real time. The efficiency and flexibility of this approach enables early engagement with the multi-disciplinary subsurface team and improves the quality of the reservoir description. In this paper, we apply this workflow to a pre-salt 4D dataset. The results show improved flood front delineation, with multi-scenario predictions that can be assimilated in reservoir models in collaboration with the integrated team.

Introduction 4D seismic attribute maps, i.e. (normalised) difference of rootmean-square amplitudes, (N)dRMS, RMS amplitudes of seismic difference (RMSDiff), are routinely used to identify swept areas together with injection/production data and reservoir simulation. However, we cannot infer saturation changes directly from the attribute maps. Another challenge is the limited vertical resolution of the flood front from 4D seismic volumes due to wavelet side lobes effect and interference from differential sweeping. Interference is exacerbated for wells undergoing water alternating gas (WAG) injection – a common recovery scheme in the Brazil pre-salt – as 4D signals at different depths may overlap with their sidelobes above and below. Many machine learning (ML) workflows are map-based (Cao and Ray 2017, Xue, et al., 2019, Zhang, et al, 2021, Maleki, et al. 2022) and do not account for the vertical resolution. Model-based 4D probabilistic inversion (Kumar and Kleemeyer, 2013; Xue, 2013; Tian, et al., 2014) can quantify reservoir property changes and provide uncertainty estimates. However, it requires sophisticated inversion efforts to match both seismic baseline and 4D difference, and multiple models may be required to capture the full range of uncertainties in static and dynamic properties. Consequently, the turnaround time for model-based 4D probabilistic inversion can extend from weeks to months. A DL inversion technique based on U-Net (Ronneberger, et. al, 2015) has been applied to a variety of geoscience problems

for feature extraction, classification and regression (Maxwell, et al., 2020, Zhang, et al., 2022, Duan. et al., 2020, Yang et al., 2022) and image based 4D seismic inversion (Li and Li, 2021, Kaur., et al. 2022). Benefiting from its U-shape architecture with a sequence of up-convolutions and concatenations, U-Net can precisely identify, locate, and quantify the output features from the input data, and has demonstrated improvements over conventional regularised inversion. In the pre-salt case study, we found that DL inversion results can provide high resolution saturation interpretation (vertically and laterally) and return discrete multi-scenario predictions for subsequent use in reservoir modelling. Seismic inversion staircase Determining which inversion approach to employ is case-dependent: depending on factors such as reservoir heterogeneity, seismic data quality, the timing of acquired seismic baseline, reservoir model (RM) quality and which decisions to impact, etc. Fit-forpurpose approaches with proper uncertainty quantification are increasing in popularity as they aim to improve decision quality and maximise value. Guided by the fit-for-purpose strategy, we categorise the commonly used 4D inversion approaches into the following staircase (Figure 1): • Map-based inversion of the 4D attribute maps including the basic QI method.

Shell International Exploration and Production | 2Shell Global Solutions UK

Corresponding author, E-mail: y.xue@shell.com

DOI: 10.3997/1365-2397.fb2023069

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Figure 1 4D seismic inversion staircase following the fit-for-purpose guidance.

• Map-based inversion of the 4D attribute maps using the extended QI method and ML/DL • Trace-based inversion using 4D seismic waveforms including probabilistic and deep learning for vertical resolution enhancement. Step 1: Basic 4D attributes inversion (map-based)

The feasibility of this option can be assessed in different ways (Slater et al. 2002, MacBeth 2004, MacBeth et al. 2006), including rock-physics modelling, historical well data via a reservoir simulator. In some settings, e.g., single-loop reservoirs, simple porosity and Net-to-Gross (NTG) distributions, homogenous sweep, good data quality, simplified approximation between reservoir property changes and 4D seismic responses (i.e., seismic reflection coefficient or impedance) and 4D seismic attribute maps can be established. Step 2: Extended 4D attributes inversion using ML/DL (map-based)

Given a wider distribution of reservoir properties (e.g. NTG, porosity, saturation baseline), more advanced ML models (Cao and Ray 2017, Xue, et al., 2019, Zhang, et al, 2021) can be used to directly link multiple 4D attribute maps and interval average of baseline properties to the interval average of reservoir property changes. Corte et al. (2019), and Dramsch et al. (2019) applied Deep Neural network (DNN) to separate pressure and saturation changes by adding 4D AVO-related attribute maps. The extended version of map-based approaches utilising ML/ DL-based models can efficiently accommodate a wide range of baseline settings but is still limited to tank-type reservoirs. For reservoirs involving vertical heterogeneity, trace-based inversion is needed. Step 3: 4D seismic data inversion (trace-based)

Among conventional trace-based approaches, 4D probabilistic seismic inversion is commonly used to improve vertical resolution. The reservoir property changes, or (relative) changes in acoustic impedance are calculated from the differences in seismic amplitudes between baseline and monitor surveys, i.e., Kumar 30

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and Kleemeyer, 2013, Xue, 2013; Tian, et al., 2014, Rosa, et al (2020, 2022). It usually starts from an initial model with a prior distribution, and iteratively updates the model to minimise the misfit with the observed 4D seismic difference. By design, the inversion results from these approaches will have a minimised misfit when compared to the real seismic data. However, it usually requires a good starting model which matches the baseline seismic data first. It can be challenging to identify if the high frequency features inverted from the probabilistic approaches are real signals or just an artefact of Monte Carlo sampling. Additionally, the posterior property distribution is highly dependent on the prior distribution and the way the iterative optimisation is defined. We will explain how we use deep learning techniques to improve the vertical resolution of 4D seismic inversion while honouring geological interpretations from multi-scenarios in the next section. Trace-based 4D Seismic DL inversion workflow Generating relevant training datasets is the most critical step of the DL-based inversion workflow, which usually starts with synthetic seismic modelling from reservoir simulation outputs. Adding interpretation-guided training datasets differentiates this approach from other DL based techniques. The workflow comprises four parts: Part 1: Generate physics-based synthetic data for training

We use a seismic well tied wavelet, petro-elastic model and 1D convolutional modelling to generate synthetic 3D/4D data from a given scenario of baseline and monitor reservoir properties. Independent synthetic Gaussian noise matching the noise level of real data were added to both baseline seismic and monitor to mimic the real data. As input, each training dataset consists of traces of baseline, monitor, and time-aligned differences; and output: the corresponding saturation changes. The training datasets need to be case dependent. We will show how to construct representative training datasets covering multi-scenarios in the real data example.

TECHNICAL ARTICLE

Part 2: Train the model (U-Net)

For each scenario, we randomly split the synthetic datasets in half. Half of them are used for training and validation, the other half are used for testing in Part 3. The CNN with the U-Net architecture was used to train iteratively until the validation loss reaches a minimum, or when a pre-defined tolerance is achieved. For computational efficiency, we only select samples within a defined gate along each trace, where the top and bottom of the reservoir and their wavelet sidelobes are well covered. Part 3: Test the trained model

After reaching a threshold accuracy from training and validation, we test the performance of the trained model using the other half of the synthetic data. If the prediction has a good match with the ground truth of the training data, we then move to Part 4 to predict on the real 4D seismic data. Otherwise, hyperparameter tuning (i.e., learning rate, layer depth, misfit function, etc.) needs to be performed and Part 2 is repeated until the threshold accuracy has been achieved. Part 4: Use the trained DL model (U-Net) to predict on the real 4D seismic data

Once the model is trained, the prediction is almost instant. Since we may have different DL models learnt from different training datasets generated from multi-scenarios, we will have different predictions which represent them. Real data example We applied this workflow to the 4D seismic data (Cruz et al., 2021) acquired from a deepwater Brazil thick pre-salt carbonate reservoir where both water injection and water alternating gas (WAG) techniques are utilised to improve the recovery. Due to the reservoir heterogeneity, it is important to understand the differential reservoir sweep to enable proactive reservoir management. An empirical petro-elastic model (Sun, 2000) was used to produce synthetic seismic data, which has been calibrated at the well locations. Given the stiff carbonate framework and the weak 4D signal observed, the pressure changes are small enough to be

4D attributes

Description

(N)dRMS

(Normalised) Difference of root mean square amplitude between baseline and monitor

dSNA

Difference of summation of negative amplitude between baseline and monitor

dSPA

Difference of summation of positive amplitude between baseline and monitor

Table 1 Commonly used 4D seismic attributes and how they are calculated.

ignored. The 4D signal is dominated by the fluid replacement, either from water injectors, Water Alternating Gas (WAG) injectors, or gas injection wells. Real data example – reasoning for DL inversion

We evaluate the feasibility of map-based approaches by upscaling sublayer in the RM into one layer to calculate the average static properties and saturation maps per stratigraphic unit. Per stratigraphic unit, we cross plot some commonly used synthetic 4D attributes (Table 1) against the mean saturation changes. The cross plots indicate a complex non-linear relationship, which is impacted by other properties, i.e. porosity (Figure 2) and gas saturation changes (Figure 3). The seismic baseline was acquired after ~five years’ production history (not constant water and gas saturation for the baseline) and the variable sign of seismic baseline amplitude makes the relationship even more challenging. Furthermore, differential sweeping features are observed in history-matched reservoir simulations, which leads to asymmetric side lobes of synthetic 4D seismic difference (Figure 4). Mapbased approaches using 4D seismic attributes do not take the shape of seismic waveforms into account and cannot provide sufficient vertical resolution; therefore, trace-based inversion was chosen. However, conventional model-based 4D seismic inversion is challenging in this setting given that inversion is typically performed on discrete model realisations, thus not fully accounting for the uncertainty in static and dynamic properties. Therefore, we chose DL inversion workflow and constructed different training datasets covering the uncertainty ranges of

Figure 2 Crossplot of dSw vs. a variety of synthetic 4D attributes: NdRMS (top left), dRMS (bottom left), dSNA (top right) and dSPA (bottom right) coloured by porosity at the upscaled layer.

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Figure 3 Cross plot of dSw vs. a variety of synthetic 4D attributes: NdRMS (top left), dRMS (bottom left), dSNA (top right) and dSPA (bottom right) coloured by dSg at the upscaled layer.

Figure 4 An example of dSw sweeping profile from RM simulation around one water injector (top) and the synthetic 4D seismic response (bottom).

reservoir properties, guided by both interpretation scenarios and RM simulation. Details will be explained in the next section. Real data example – Part 1: generate training datasets

Generating good training datasets is the most critical step for a successful DL trace-based inversion. Good training datasets should be both a) representative: honouring geology, physics and consistent with interpretation; and b) diverse enough to cover the uncertainty range of both static and dynamic parameters. A good starting point is to run a 4D check the loop, which compares the synthetic seismic response generated from reservoir simulation using a rock physics model with the real seismic observations, to identify any gaps. From the 4D check the loop, we found the observed 4D seismic signal is much weaker than the synthetic 4D from reservoir simulation. One interpretation is water or gas may sweep along 32

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high permeability streaks, as the magnitude of 4D signal is not only dependent on saturation changes, but also on swept interval thickness. Those high permeability streaks may not be optimally captured at the simulation grid scale, therefore we generated alternative sweep scenarios (water sweep and gas sweep in high permeability sublayers) to complement DL models, consistent with the cyclicity present within the pre-salt Brazil Barra Velha Formation (e.g. Wright and Barnett, 2015). Other contributors to the mismatch may come from a rock physics model and rock fluid interaction effects; their sensitivities on the 4D signal are out of this paper’s scope. In this example we have different training datasets: one group is generated from history-matched RM simulation models, the other group will be guided by the alternative sweep scenarios, to include training information not contained in RMs. In the water sweep scenario, we subdivided the uppermost Barra Velha (BVE100) interval, where the majority of 4D signals are observed, into three sublayers. The number of layers is defined based on a balance between the seismic resolution and improved vertical resolution for the enhanced interpretation. To cover the uncertainty range for both static and dynamic parameters, we sampled the porosity uniformly along the inline direction, with water saturation changes (dSw) increasing in the crossline direction in the sweep scenario models. We built seven sub-scenarios to encompass all of the differential sweep permutations (Figure 5). The corresponding synthetic 4D seismic responses are displayed in Figure 6. The same workflow was applied to generate gas sweep scenarios by simply replacing dSw increase with gas saturation change (dSg) increase.

Figure 5 Table outlining the seven sweep scenarios to cover all possible differential sweep scenarios. Water swept layers correspond to the blue cells.

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Figure 6 A traverse view of water saturation change (1st row) and their synthetic seismic difference after time-alignment (2nd row) of the seven water sweep scenarios defined in Figure 5.

From Figure 6, we can see if only one sublayer was swept (i.e., S1, S4, S5), the time-aligned seismic difference is much weaker than when a full layer is swept (S3), given the same magnitude of porosity and saturation changes. Furthermore, we can observe that the asymmetric side lobes of time-aligned difference correlate with the location of sweeping, but the relationship is not consistent between scenarios due to its dependency on both baseline and monitor seismic, driven by the porosity and saturation change distribution. It is difficult for interpreters

to connect fine seismic features to the corresponding scenarios, but U-Net can easily handle highly complex connections. The sweep scenarios were designed for inversion of dSw increase only and dSg increase only, while the RM simulation scenario (Figures 7, 8 and 9) was used for the simultaneous inversion of dSg and dSw around WAG wells as it provides constraints on the saturation distribution. Independent synthetic Gaussian noise matching the noise level of real data were added to both baseline seismic and monitor

Figure 7 Example of time-aligned synthetic seismic difference from RM simulation using the same traverse as in Figures 8 and 9.

Figure 8 Comparison of predicted dSw (bottom) with the ground truth of the RM simulated dSw (top) along the same traverse as Figure 7.

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Figure 9 Comparison of predicted dSg (bottom) with the ground truth of the RM simulated dSg (top) along the same traverse as Figure 7.

Figure 10 QC at randomly selected trace locations from the testing data. For each trace location, left column: seismic baseline (blue), monitor (magenta); middle column: time-aligned difference (black); right column: the predicted dSw traces (green) and the ground truth of the RM simulated dSw traces (red). For all the plots: x-axis is the normalised magnitude, y-axis is number of samples for each trace with a sampling rate of 1ms.

to mimic the real data and support for a robust prediction for the real data, but only to a certain degree as those are not representative of real 4D noise. Real data example – Part 2 & 3: train/test the model

We set up U-Nets and trained them separately with the datasets from reservoir simulation outputs, water-replacing-oil and gas-replacing-oil alternative sweep scenarios. The training had validation accuracy of 0.85, 0.83 and 0.91, respectively. Testing data showed similar performance. To visualise how well the predicted saturation changes from the testing data matched the ground truth of the RM simulation, we plotted them together at two randomly selected traces (Figure 10) and observed that the locations of differential sweep were very well captured with very small residuals. Furthermore, to explore how well the lateral continuity is preserved, we tested using the RM-derived synthetic seismic as input (Figure 7) and compared the predicted saturation changes with the ground truth of the RM simulated saturation changes (Figures 8 and 9). Although not all fine scale features are captured due to the band-limited nature of seismic data, the predicted sweeping profile matches excellently with the RM simulation in shape, location, and magnitude. 34

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Real data example – Part 4: prediction

In the last step, the trained U-Nets from those scenarios were applied to predict saturation changes from the real seismic baseline, monitor and time-aligned difference volumes. Here we show an example of predictions around one water injector using training datasets from 1) water sweep scenario; 2) RM simulation scenario – in both traverse view and map view (Figure 11). When compared to the time-aligned seismic difference, the inverted dSw profiles from both scenarios provide a much cleaner image with higher resolution details for analysis of the reservoir sweep (Figure 11). A clearer water flood front was demonstrated in the map view too, when compared with the 4D attribute map. The dSw results from the model trained using the alternative sweep scenarios, produce a geologically credible, high resolution waterflood result. Given the inherent subsurface uncertainties and lack of ground truth, rather than picking the best solution, we consider each solution is helpful in different ways at different locations. For example, the solution from sweep scenarios only simulating two phase changes may not well represent what may have happened around WAG wells, and may not honour mass balance, but is very useful to identify the possible differential sweeping features away from water and gas injectors. The RM simulation-guided scenario may have a better representation around the

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Figure 11 An example of dSw prediction around one water injector. From top down in the left: a traverse view of real seismic difference after time-alignment (top), predicted dSw from water sweep scenario (middle), predicted dSw from RM simulation scenario (bottom). From top down in the right: map of 4D attribute RMSDiff (top), predicted dSw from water sweep scenario (middle), dSw from RM simulation scenario (bottom).

WAG wells, but be less sensitive to thin layer sweeping features away from water/gas injectors. Currently, all the inversion results are being used for enhanced interpretation with improved vertical resolution and for effective communication between different disciplines.

To quantify the uncertainties from the DL inversion (U-net model), a commonly applied approach is to run the training multiple times and calculate the mean and the standard deviations of the predictions from those trained models (Dramsch et al. 2019). 3) Interpretation uncertainty

Way forward – uncertainty quantification Uncertainty quantification is very important, especially when finite numbers of inversion output are used for decision making. In this paper, we only discuss the uncertainty framework. The future direction of this research is to establish how the uncertainty from these techniques can be captured and quantified. 1) Seismic data uncertainty

Practically, different processing vintages might be used in the prediction step to generate multiple inversion outputs to capture the uncertainty from seismic data processing and different velocity models. Additionally, different types of synthetic noise can be added to the training dataset to improve the robustness of trained model and to quantify the impact of noise and the uncertainties associated with it. If good quality subsets of seismic data are available, such as angle gathers and/or their time-aligned differences and/or 4D amplitude versus offset (AVO) volumes, they can be used in the DL inversion workflow to further reduce uncertainty. Feasibility tests on synthetic data should be done first. 2) Model uncertainty

The major model uncertainties reside in a) petro-elastic models; b) RMs; c) DL models. The first two types of uncertainties can be evaluated from the forward modelling: generating different groups of training datasets by using different petro-elastic models and RMs, and saving the trained models accordingly to predict on the real datasets. The variation in predictions reflect the sensitivity of the inversion results to those different petro-elastic and/or RMs.

Different people may have different interpretations on the same signal they observe, i.e. hardening signal could be due to water injection, or due to compaction or due to gas back to solution or due to oil saturation decrease or a combination of those. For the conventional probabilistic inversion method under Bayesian framework, users can set which parameters to be perturbed based on the interpretations, but the optimisation process usually introduces perturbations in a relative random way, as it is not straightforward to add correlation constraints of perturbation at different sublayers in a reservoir. For the DL-based approaches, we have the flexibility to generate a large number of realisations following geology and their waveform patterns are very well represented in the synthetic training datasets. In this way, we can invert for the scenarios which may not be well represented in the reservoir simulation but are possible from geological interpretations. Conclusions We built a seismic inversion staircase to design a fit-for-purpose 4D seismic inversion strategy for different types of reservoirs and decisions to influence. For a single connected tank type reservoir, map-based inversion can provide an 80% solution of the reservoir property changes as an interval average. For decisions requiring improved vertical resolution, trace-based inversion with dedicated design and more computation power is needed. For heterogenous reservoirs with higher uncertainty in static and dynamic properties, trace-based inversion using DL techniques (e.g. U-net) has the advantage of learning from multiple groups of training datasets from different scenarios guided by multi-disciplinary integration. FIRST

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In the Brazil pre-salt 4D seismic example, we analysed synthetic modelling and selected the trace-based inversion using the DL technique. Providing interpretation-guided sweep scenarios to supplement reservoir simulation outputs as part of the training can efficiently incorporate the uncertainty range of RMs into prediction and can effectively recognise important fine features when making predictions on real seismic data. These results provide an opportunity to analyse differential sweep patterns and improve reservoir characterisation. This workflow can reduce the cycle time of conventional 4D seismic inversion from months/weeks to weeks/days with almost real time prediction after the U-Net is trained. It is less dependent on the availability and realisations of RMs and allows interpreter-defined scenarios to drive the prediction, filling information gaps in RMs. The quality of the result was validated by matching DL outputs with RM ground truth and by generating results that improved multi-disciplinary integration in a pre-salt case study. This workflow enables us to capture the model and interpretation uncertainties through constructing different groups of training datasets. We will further improve the method by benchmarking it with traditional 4D inversion and quantitative interpretation approaches. Furthermore, this work is not limited to predict saturation changes only, and can be extended to predict pressure changes by adding more relevant seismic data (i.e. PS data, AVO data, time shifts) to the modelling and training process.

Li, B. and Li, Y.E. [2021]. Neural network-based CO2 interpretation from

Acknowledgements The authors would like to thank Petrobras and Galp for permission to publish these results and to Shell colleagues for their feedback.

Slater C.P., Fletcher, J., Walder, D., Marsh, J. and MacGregor, J. [2002].

4D Sleipner seismic images. Journal of Geophysical Research: Solid Earth, 126, https://doi.org/10.1029/2021JB022524. MacBeth, Floricich, C.M. and Soldo, J. [2006]. Going quantitative with 4D seismic analysis, Geophysical Prospecting, 2006, 54, 303-317. MacBeth, C. [2004]. A classification for the pressure sensitivity properties of a sandstone rockframe. Geophysics, 69, 497-510. Maleki, M., Cirne, M., José Schiozer, D., Davolio, A. and Rocha, A. [2022]. A machine-learning framework to estimate saturation changes from 4D seismic data using reservoir models, Geophysical Prospecting, 70, 1388-1409. https://doi.org/10.1111/1365-2478.13249 Maxwell, A., Bester, M., Guillen, L., Ramezan, C., Carpinello, D., Fan, Y., Hartley, M., Maynard, S. and Pyron, J. [2020]. Semantic Segmentation Deep Learning for Extracting Surface Mine Extents from Historic Topographic Maps, Remote Sensing, 12(24), 4145; https:// doi.org/10.3390/rs12244145. Rosa, D.R., Santos, J.M.C., Souza, R.M., Grana, D., Schiozer, D.J., Davolio, A. and Wang, Y. [2020]. Comparing different approaches of time-lapse seismic inversion, Journal of Petroleum Science and Engineering, 17, 929-939. Rosa, D.R., Schiozer, D. J. and Davolio, A. [2022]. Enhancing vertical resolution with 4D seismic inversion, Journal of Petroleum Science and Engineering, 212, 110291. Ronneberger, O., Fisher, P.and Brox, T. [2015]. U-Net: convolutional networks for biomedical image segmentation, https://arxiv.org/ abs/1505.04597. 4D monitoring of Schiehallion Field, UKCS. 64th EAGE Conference, Florence, Italy, Extended Abstracts, A025. Sun, Y.F. [2000]. Core-log-seismic integration in hemipelagic marine sediments on the eastern flank of the Juan de Fuca Ridge, Proceedings of

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Robust and high resolution imaging of limitedaperture DAS VSP Herurisa Rusmanugroho1* and Makky Sandra Jaya1.

Abstract Distributed acoustic sensing (DAS) data recording a large amount of the subsurface information become more promising for real-time seismic monitoring. Therefore, fast and accurate imaging techniques are required to handle large datasets. Besides the issue of the computation cost, most of the migration methods, such as reverse-time migration (RTM) and Kirchhoff migration suffer from the artifacts, influencing the quality of the image, because of the limited-aperture data. Here, we perform a migration, based upon the Fresnel volume on the simulated geophone VSP and DAS VSP acquired by newly developed fibre-optic cables in Canada. We show that the Fresnel volume migration with a competitive runtime is superior and robust compared to the RTM and Kirchhoff migration. The angle-domain common-image gathers (ADCIGs) extracted from the Fresnel volume migration is more reliable and cleaner than that of the conventional Kirchhoff migration, used further for the AVO analysis and inversion.

Introduction Based on the concept of the Rayleigh scattering, distributed acoustic sensing (DAS) VSP recording subsurface deformation measures the phase change of the light wave backscattered by the fibre inhomogeneity. In contrast to the geophone VSP, the DAS VSP with the sensors (channels) distributed continuously along the cable and installed over a large distance provides a large volume of data. The applications of DAS VSP include reservoir monitoring and seismic imaging. For time-lapse reservoir monitoring, Mateeva et al. (2013) note that the DAS permanently installed provides high data-repeatability and economical acquisition, compared to the geophone. Ghazali et al. (2018, 2019) improve the image of the sandstone reservoirs beneath the gas clouds at the Malaysia’s field, by combining the images obtained from the reverse-time migration with multiples (RTMM) of 3D DAS VSP and OBN data. The RTMM of the wide-azimuth DAS extends the reflection illumination away from the boreholes. Using the same dataset, Muhammed et al. (2019) show that the noise from the oil production can be easily removed by using the FX filter. As shown by Willis et al. (2016), the other advantage over geophone VSP is that DAS VSP cemented behind casing is insensitive to the tube waves commonly considered as a noise. Since our recorded data is band-limited, considering seismic wave propagating as a group of rays, often known as Fresnel volume, is more realistic than a single ray. The Fresnel volume, for example, is obtained by the paraxial ray tracing (Červený and Soares, 1992) or by the eikonal equation (e.g., Watanabe et al., 1999). The Fresnel volume of the reflected wave is calculated based on the inner Fresnel zone on the reflector, where the constructive interference occurs. In fact, the Fresnel volume

limits only the diffraction points significantly contributing to the recorded data. The concept of the Fresnel volume is frequently used for seismic imaging (e.g., Schleicher et al., 1997; Buske et al., 2009) and seismic inversion (e.g., Watanabe et al., 1999; Rusmanugroho et al., 2017). Kirchhoff migration and reverse-time migration (RTM) are widely used in industry. Kirchhoff migration offers a fast computation and flexibility of using the input data, either common-shot or common-offset gathers, and provides a high-frequency image, but its migrated image is often noisy due to the nature of the finite-frequency data. By contrast, RTM is computationally expensive, but is capable of handling more complex structures and producing high S/N image. However, both migration methods suffer from the migration artifacts because of the limited-aperture data (e.g., Rusmanugroho et al., 2021, 2022). In this paper, we provide a theoretical framework of a migration based on the Fresnel volume (FVM) and its implementation to the synthetic VSP. We also apply FVM to the field’s DAS VSP acquired using the newly developed cables and then compare its migrated image to that of the standard Kirchhoff pre-stack depth migration and RTM. Theoretical framework Following (e.g., Schneider, 1978), the Kirchhoff integral, an integral form of the wave equation, is expressed as (1) where m is an image point, w is a weight function for compensating the obliquity and geometrical spreading, is a time

PETRONAS

Corresponding author, E-mail: herurisa.rusmanugro@petronas.com

DOI: 10.3997/1365-2397.fb2023070

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derivative of the recorded data, and (tS + tR) is a traveltime of P-wave corresponding to a pair of the source and receiver and the image point. This equation is generally called a diffraction stack migration, summing up the amplitudes along the diffraction curve, and then assigning the summed amplitude to the subsurface image point. Following Buske et al. (2009), inserting an additional weight function into equation (1) results

(4)

where

and

are phase slowness vectors obtained

by taking the spatial derivative of the traveltimes TS and TR, respectively, from the source and receiver. Here, the ADCIGs are used to analyse the amplitude variation with offset (AVO) influenced by the physical properties such as wave speeds and density.

(2) where WF is calculated based upon the Fresnel volume (e.g., Červený and Soares, 1992) on the isochron, a line or surface of constant traveltime, defined as follows

(3)

where d is the difference of the two-way traveltimes through the reference and surrounding image-points,

, is the radius of

the first Fresnel zone and f is a dominant frequency. See Watanabe et al. (1999) for the details. In equation (3), the weight of tapers out the Fresnel zone. The reflected Fresnel volume is a superposition of the transmitted Fresnel volume of the diffraction points (Červený and Soares, 1992). Unlike the Kirchhoff integral, the presence of WF in equation (2) maps the recorded amplitude onto the area within the Fresnel zone. In the case of the limited-aperture data, including mapping the amplitude on the outer Fresnel zone produces false events (artifacts) and potentially removes dipping structures in the migrated image (Yilmaz, 2001). Following Liu et al. (2018), the opening angle of the reflection for extracting angle-domain common-image gathers (ADCIGs) is estimated as

Testing and results Firstly, we test the two different approaches [equations (1) and (2)] using the simulated VSP data. Then, we continue to apply them to the DAS data acquired in Canada’s field, which are limited in coverage (both near and far offsets). As a comparison, we migrate the DAS data using RTM (e.g., McMechan, 1983). Finally, we analyse the migrated image of the three methods including their extracted ADCIGs. Synthetic data The P-velocity model consisting of two flat-reflectors for simulating VSP data is shown in Figure 1a. The size of the model is 183 × 112 grid points with 2 and 5 m spacing (364 m × 555 m). The red triangles show the location of 60 sources at depth of 0 m, expanding from 0 m to 364 m. The well is located at (X, Z) = (180 m, 0 m). The blue triangles indicate the depth of the geophones on the borehole, ranging from 0 m to 555 m with 5 m spacing. The 2D acoustic wave equation is solved using the eighth-order finite differencing (Rusmanugroho and McMechan, 2010). The sides and bottom of the model are set to the Higdon’s boundary condition (Higdon, 1987). The wavelet used for the simulation is Ricker with a dominant frequency of 50 Hz. Figure 1b shows the representative common-source-gather VSP, shot at (X, Z) = (175.9 m, 0.0 m). Since we are interested in imaging the reflectors, the first arrival is removed before being used for the migrations. The upgoing primaries, interbed downgoing multiple and interbed upgoing multiple are seen. The multiples are much weaker than the primaries. Figure 2a and b show the Fresnel volume of the P-wave corresponding to the same receiver at (X, Z) = (180 m, 100 m) and the sources at (X, Z) = (0 m, 0 m) and (X, Z) = (364 m, 0 m),

Figure 1 a) P-wave model consisting of two flatreflectors for generating synthetic VSP data and b) representative common-shot-gather VSP. In a, the red and blue triangles show source and receiver locations, respectively. In b, the first arrival is removed before being used for the migrations.

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Figure 2 Fresnel volume (non-zero values) of P-wave transmitted and reflected by some part of a) the first reflector and b) the second reflector. The red and blue triangles correspond to the source and receiver locations. The dashed white line indicates the reflectors.

Figure 3 Migrated image of the two flat-reflectors (see Figure 1a for the model) from a) reverse time migration (RTM), b) Kirchhoff migration and c) Fresnel volume migration (FVM), stacked over 60 sources. Both RTM and Kirchhoff migration suffers from the migration artifacts. Meanwhile, the image of FVM is crisp, high-resolution and robust to the limitation of the data aperture.

respectively, reflected by the first and second reflectors shown by the dashed white line. Here, we understand that the amplitudes recorded at the receiver mainly come from small portions (inside the Fresnel zone) of the reflectors only. The radius of the Fresnel volume [rF in equation (3)] is determined by the dominant frequency of the recorded data. The higher frequency the smaller the radius; theoretically, The Fresnel volume becomes as small as a single ray at the highest frequency. The Fresnel volume is used as a weight function during the migration [equation (2)]. Figure 3 shows the image of the two flat-reflectors obtained from a) RTM, b) Kirchhoff migration [equation (1)] and c) FVM [equation (2)]. The three migrated images are consistent kinematically. By comparing with the image of the Kirchhoff migration and FVM, the RTM’s image is low frequency due to the wave equation numerically solved by the finite difference method. The FVM provides a superior image. The truncated aperture (Yilmaz, 2001) primarily causes the migration artifacts in Figures 3a and b. By excluding the contributions of the diffraction points on the outer Fresnel volume, where the destructive interference occurs, the FVM removes the edge artifacts and the structural ambigui-

ties, and sharpens the migrated image. The concept of the Fresnel volume is also connected to the proposed imaging condition of RTM and finite-frequency sensitivity kernels of full-waveform inversion (Rusmanugroho et al., 2017). The high-resolution RTM for DAS data is very computationally expensive since the distance or depth between two receivers can be 0.2 m. The smaller grid spacing and time interval are required to satisfy the Courant-Friedrichs-Lewy (CFL) condition. Therefore, we are focusing on discussing further Kirchhoff migration and FVM implementations later. Figure 4 shows angle-domain common-image gathers (ADCIGs) from Kirchhoff migration and FVM, extracted off the well, at X = 230 m. The incidence angle or half opening-angle formulated in equation (4) is estimated using the slowness vector from a pair of source and receiver. The final incidence angle is summed over the individual calculations of source and receiver. In the example of VSP data, we see that the Kirchhoff migration produces the artificial CIG (artifacts) at near and mid-offsets since the events at near incidence angles are not recorded in the data. FIRST

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Figure 4 Angle-domain common-image gathers (ADCIGs) ranging from 0˚ to 30˚, extracted from a) Kirchhoff migration and b) FVM, off the well, at X = 230 m (see Figure 1a for the well location). The CIG of Kirchhoff migration shows migration artifacts caused by unavailable narrow-aperture data.

Field data Figure 5 shows a source distribution of a walkway VSP acquired by the fibre-optic cables tested in Canada. Each blue dot is one of 37 3C vibroseis sources producing P-, SH- and, SV-waves. The distance between two sources is 10.24 m. The borehole shown by the orange cross is located at (X, Y) = (116.7, 149.0) m. The strain changes are measured by the sensors distributed along the cable from 20 m to 364 m depth with a 0.2 m interval; the total channels are 1621. The distance between the farthest shot and well is only about 179 m. The image points depending on the depth are limited-incidence angles, for example ranging from 5˚ to 25˚. With this aperture limitation, the VSP data may not be ideal for conventional seismic imaging and inversion (Rusmanugroho and McMechan, 2012). The cable development solves the problem of insensitive response of optical fibre when it is perpendicular to the incoming seismic wave. In the case of helically-wound optical fibre, the development improves the response of the cable to the transverse wave. The development also maintains the high-resolution response while using a smaller-size cable. The details of the cable development are found in Kishida et al. (2022). The signal of the developed cables is interrogated using the time gated digital-optical frequency domain reflectometry (TGD-OFDR) technique (Kishida et al., 2021). The geophone VSP is also acquired near the base of the well, used to calibrate the depth of the DAS sensors. Before the calibration, integrating in time the strain-rate of the DAS is necessary to match the displacement-gradient of the geophone (Näsholm et al., 2022). Since the DAS covers the entire section of the borehole, the velocity model used for migrating the geophone data is extended for migrating the DAS data. The CO2 injection target intervals of the studied field are primarily from water-filled sandstone formations, which are ~300 m deep with the thickness of 200 m, and ~500 m deep with a thickness of 60 m. The overlying caprocks are predominantly shales. At shallow depth, a 24 m low-velocity-layer of glacial deposits and soils overlays the truncated bedrock (Lawton et al., 2017). Figure 6 shows representative shot gathers of the upgoing wavefield of the fibre-optic DAS VSP, produced by P-wave vibroseis source. The shot gathers are generated by the shots 1, 40

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19 and 37, respectively, located at (X, Y) = (215.5, 288.9), (125.6, 169.0), and (0.0, 0.0) m. The processing workflow of the DAS VSP primarily follows that of the geophone VSP, as described in Hinds et al. (1996), including the wavefield separation, shot static corrections, deconvolution and VSP-CDP transformation. The upgoing and downgoing wavefields are separated by using the median filter, and then the upgoing wave is enhanced by the FK filter. The deconvolution of the upgoing wave is obtained using a deconvolution operator obtained from the downgoing wave because of the signal strength. Besides the reflected P-wave, the converted S-wave is obviously seen in the shot gathers 1 and 37. The frequency of the DAS VSP ranges from 10 Hz to 150 Hz, wider than that of the geophone VSP. The peak frequency of the DAS VSP is ~92 Hz. During the acquisition, an inflatable liner is used to couple the optical fibre with the side of the well.

Figure 5 Source distribution of a walkaway DAS VSP (blue dot). The orange cross shows the well location. The distance between two sources is 10.24 m. The distance between the farthest shot and well is about 179.0 m.

TECHNICAL ARTICLE

Figure 6 Representative common shot gathers of newly developed, time-gated digital DAS VSP from shots a) 1, b) 19 and c) 37 (see Figure 5 for the shot locations).

Figure 7 Representative a) source, b) receiver and c) (source + receiver) traveltimes superimposed on smooth P-velocity (colour) used for seismic imaging. In b, the white line shows the location of the well. The blue and red triangles indicate source and receiver locations.

In Figures 7a and b, each contour line shows a constant time (isochron) of P-wave travelling from the image points to the source and receiver locations, respectively, indicated by the red and blue triangles, superimposed on a smooth P-velocity model used for the migrations. In Figure 7c, the contour lines show the two-way traveltimes with respect to each image point in the surface model. Following (e.g., Vidale, 1988; Qin et al., 1992), the traveltime is calculated by solving the eikonal equation. The two-way traveltime is used for calculating the Fresnel volume as the input for FVM. The size of P-velocity model is 183 × 555 grid points with 2 and 1 m spacing (364 m × 555 m) used for the migrations. The P-velocity is estimated by minimising the observed and calculated traveltime data in the tomography inversion. The P-velocity shows that nearly horizontal layers dominate the overall structure of the studied area. At shallow depth, the low velocity ~570 m/s indicates the weathering layer. The gauge length of the fibre-optic cable is 0.2 m. To reduce the computation time, we skip the sensors (channels) in the

data by fives to match the 1-m grid interval in the migrations. Before the migrations, we normalise the input gathers to reduce the directivity dependencies. We resample the data to obtain a 0.0002 s time-interval in order to maintain the CFL’s stability condition in RTM. Figure 8 shows the migrated image of RTM, Kirchhoff migration and FVM, applied to the limited-aperture data. Generally, the three migrated images are consistent kinematically. In terms of resolution, RTM is the lowest and Kirchhoff migration is the highest. Compared with the the Kirchhoff migration, we lost some high frequencies in the FVM since the contributions of the data are limited below the dominant frequency [see equation (3) for clarity]. We see that both the RTM and Kirchhoff migration from the field data suffer from the migration artifacts, similar to that from the simulated data. The RTM image is only focused in the area near the borehole, ~200 m. Meanwhile, the Kirchhoff migration and FVM expand their image away from 100 m to 300 m. The FVM is superior, showing clearly the shallow-to-deep geologic structure of FIRST

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Figure 8 Migrated image stacked over 37 sources, revealing the Canada’s field structure from a) reverse time migration (RTM), b) Kirchhoff migration and c) Fresnel volume migration (FVM). Both RTM and Kirchhoff migration suffers from the migration artifacts due to the limitation of the data aperture. The image of FVM is superior to others.

Figure 9 Angle-domain common-image gathers (ADCIGs) of the Canada’s field, extracted from a) Kirchhoff migration and b) FVM, off the well at X = 230 m (see Figure 7b for the well location). The CIG of FVM is less noisy and more coherent than that of Kirchhoff migration.

the studied field dominated by nearly horizontal sediment layers. The RTM, Kirchhoff migration and FVM summed over 37 sources are performed on a single processor machine with the runtime of ~148, ~19, and ~39 minutes, respectively. By comparing the runtime of the RTM, the runtimes of the FVM and Kirchhoff migration are competitive. The computation cost of the FVM is higher than the Kirchhoff migration primarily due to on-the-fly calculation of the weight function saving the use of the hard disk space. Precomputing the weight function is able to reduce the runtime of FVM. Figure 9 shows angle-domain common-image gathers (ADCIGs) from Kirchhoff migration and FVM, obtained by using equation (4), extracted off the well located at X = 230 m (see Figure 7b for the well location). Besides being used in the AVO analysis, the CIGs are often used for migration velocity analysis (MVA) (e.g., Jin et al., 2014). The flatness of the events in CIGs corresponds to the correctness of the migration velocity. Here, we see that the CIG of the Kirchhoff migration is noisy and some events are not continuous, especially above 42

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300 m, primarily because of the migration artifacts coming from the near and far offsets, which are not available. In Figure 9b, the CIG of the FVM is flat, crisp and clean, compared with that of the Kirchhoff migration. Since the CIGs are extracted off the well, the near offset amplitudes are not well estimated. The events are not curved down and up indicating that the migration velocity obtained by the traveltime tomography is just right. Compared with the CIG of the Kirchhoff migration, the CIG of the FVM is definitely more reliable for the AVO analysis and inversion. Conclusions Generally, Kirchhoff pre-stack depth migration runs fast and provides a high-resolution image. It is also flexible in terms of using the input data; common-shot, common-receiver or common-offset gathers. By contrast, reverse-time migration (RTM) is computationally expensive and able to image more complex geologies. Clearly, both methods suffer from the migration artifacts when handling the limited-aperture data including near and far offsets. The field data used for our migrations involve

TECHNICAL ARTICLE

only a minimum pre-processing. In the case of VSP data, the near offsets are not always available to image the vicinity of the borehole. We show that a migration technique based on the Fresnel volume (FVM) provides a high-resolution image, improving the limitation of the Kirchhoff migration and RTM. The runtime of the FVM is about twice as much as that of the Kirchhoff migration. This runtime can be optimised by precomputing the weight function. However, it is much faster than that of the RTM, suitable for the real-time seismic monitoring, where DAS VSP records a large amount of data over time. The angle-domain common-image gathers (ADCIGs) of the FVM are crisper and cleaner than that of the Kirchhoff migration. The ADCIGs of DAS VSP support the CO2 plume migration monitoring, since they provide a direct AVO quantification.

Liu, S., Gu, H., Tang, Y., Bingkai, H., Wang, H. and Liu, D. [2018]. Angle-domain common imaging gather extraction via Kirchhoff prestack depth migration based on a traveltime table in transversely isotropic media: Journal of Geophysics and Engineering, 15(2), 568575. Mateeva, A., Lopez, J., Mestayer, J., Wills, P., Cox, B., Kiyashchenko, D., Yang, Z., Berlang, W., Detomo, R. and Grandi, S. [2013]. Distributed acoustic sensing for reservoir monitoring with VSP. The Leading Edge, 32(10), 1278-1283. McMechan, G.A. [1983]. Migration by extrapolation of time-dependent boundary values. Geophysical Prospecting, 31(3), 413-420. Muhammed, M., Rahim, M. and Ghazali, A. [2019]. Integrated shallow gas imaging using fiber optics DAS VSP and OBN. 81st EAGE Conference and Exhibition, Extended Abstracts, We_R09_15. Näsholm, S.P., Iranpour, K., Wuestefeld, A., Dando, B.D., Baird, A.F. and Oye, V. [2022]. Array signal processing on distributed acoustic

Acknowledgments We would like to thank the management of Petronas for permission to publish this work. We would also like to thank Ahmad Riza Ghazali and anonymous reviewers for their constructive comments on our manuscript.

sensing data: Directivity effects in slowness space. Journal of Geophysical Research: Solid Earth, 127(2), 413-420. Qin, F., Luo, Y., Olsen, K.B., Cai, W. and Schuster, G.T. [1992]. Finite-difference solution of the eikonal equation along expanding wavefronts. Geophysics, 57(3), 478-487. Rusmanugroho, H., Jaya, M. and Zahir, M. [2022]. Depth Imaging of

References Buske, S., Gutjahr, S. and Sick, C. [2009]. Fresnel volume migration of

Distributed Acoustic Sensing VSP. 2nd EAGE Workshop on Fiber Optic Sensing for Energy Applications in Asia Pacific, 28.

single-component seismic data. Geophysics, 74(6), WCA47-WCA55.

Rusmanugroho, H., Jaya, M., Zahir, M. and Rahim, M.F. [2021]. Pre-

Červený, V. and Soares, J.E.P. [1992]. Fresnel volume ray tracing.

Stack Depth Migration of High Resolution Distributed Acoustic

Geophysics, 57(7), 902-915. Ghazali, A.R., ElKady, N., Abd Rahim, M.F., Hardy, R.J.J., Dzulkelfi,

Sensing VSP. International Petroleum Technology Conference, IPTC21233-MS.

F.S., Chandola, S., Kumar, S., Shukri, S., Mohi Eldin, S.M.T.,

Rusmanugroho, H. and McMechan, G.A. [2010]. Modeling sensitivity

Elkurdy, S.S., Rafiuddin, N.L., Maitra, S., Basir, F.F., Ghazali, M.L.,

of 3D, 9-C wide azimuth data to changes in fluid content and crack

Abdul Latib, M.H.F. and Zainal, S. [2018]. Reservoir delineation

density in cracked reservoirs. Geophysics, 75(5), T155-T165.

beneath a heterogeneous shallow gas overburden using ‘True-3D’

Rusmanugroho, H. and McMechan, G.A. [2012]. Sensitivity of estimated

seismic imaging approaches. First Break, 36(11), 89-96. Ghazali, A.R., Abdul Rahim, M.F., Mad Zahir, M.H., Muhammad, M.D., Mohammad, M.A. and Aziz, K.M.A. [2019]. Ears on wells: Reser-

elastic moduli to completeness of wave type, measurement type, and illumination apertures at a receiver in multicomponent VSP data. Geophysics, 77(1), R1-R18.

voir delineation and monitoring using true 3D imaging approaches.

Rusmanugroho, H., Modrak, R. and Tromp, J. [2017]. Anisotropic

SPE Annual Technical Conference and Exhibition, SPE-195954-MS.

full-waveform inversion with tilt-angle recovery. Geophysics, 82(3),

Higdon, R.L. [1987]. Numerical absorbing boundary conditions for the wave equation. Mathematics of Computation, 49(179), 65-90. Hinds, R.C., Anderson, N.L. and Kuzmiski, R.D. [1996]. VSP Interpretive Processing: Theory and Practice. Society of Exploration Geophysicists. Jin, H., McMechan, G.A. and Guan, H. [2014]. Comparison of methods for extracting ADCIGs from RTM. Geophysics, 79(3), S89-S103. Kishida, K., Guzik, A., Nishiguchi, K., Li, C., Azuma, D., Liu, Q. and He, Z. [2021]. Development of real-time time gated digital (TGD) OFDR method and its performance verification. Sensors, 21(14), 4865. Kishida, K., Ghazali, A.R. and Abd Rahim, M.F. [2022]. Optical cable, optical cable monitoring system, and well monitoring method. U.S. Patent Application No. US-20220364460A1. 2022-11-17. U.S. Patent and Trademark Office. Lawton, D.C., Osadetz, K.G. and Saeedfar, A. [2017]. Monitoring technology innovation at the CaMI Field Research Station, Brooks, Alberta. CSEG GeoConvention.

R135-R151. Schleicher, J., Hubral, P., Tygel, M. and Jaya, M.S. [1997]. Minimum apertures and Fresnel zones in migration and demigration. Geophy sics, 62(1), 183-194. Schneider, W.A. [1978]. Integral formulation for migration in two and three dimensions. Geophysics, 43(1), 49-76. Vidale, J. [1988]. Finite-difference calculation of travel times. Bulletin of the Seismological Society of America, 78(6), 2062-2076. Watanabe, T., Matsuoka, T. and Ashida, Y. [1999]. Seismic traveltime tomography using Fresnel volume approach. 69th SEG Annual International Meeting, Expanded Abstracts, 1402-1405. Willis, M.E., Erdemir, C., Ellmauthaler, A., Barrios, O. and Barfoot, D. [2016]. Comparing DAS and geophone zero-offset VSP data sets side-by-side. CSEG Recorder, 41(6), 22-26. Yilmaz, Ö. [2001]. Seismic data analysis: Processing, inversion, and interpretation of seismic data. Society of Exploration Geophysicists.

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Special Topic

RESERVOIR ENGINEERING & GEOSCIENCE The need to get the most out of the largest fields has never been a bigger game, especially as many deep-water and frontier exploration projects to enhance oil recovery have become viable again. As a result, geoscientists need to raise the bar in terms of the ingenious reservoir engineering and engineering solutions that they apply. Bruno Conti et al explore the hydrocarbon potential of Uruguay’s offshore basins. Sebastien Strebelle et al present an ensemble of equiprobable models, representing the unknown reservoir properties through probability distributions, enabling assessment of project risks Bill Shea et al demonstrate the work efficiency gains that are achieved by taking a ‘multi-dimensional’ computational approach to time-lapse analysis. Lory Evano et al present a decomposition method in which geological lateral continuity is captured using a Relative Geological Time (RGT) model. Øystein Haugen Solbu et al demonstrate how the gravimetry and subsidence surveying method at the Mikkel Field in the Norwegian Sea has improved understanding. David Went et al demonstrate a highly effective method to identify hydrocarbons without any well data control in the simply buried Neogene and Paleogene (Tertiary) strata of the Mississippi Canyon. Kim Gunn Maver et al present a solution to utilise geothermal energy using a single well closed-loop system, which can reliably provide heated fluids with very limited geological requirements. Natasha MacAdam et al show how a modern WAZ 3D survey in the salt basin, combined with reservoir, trap and DHI studies demonstrate significant, ready-to-drill prospects on the Nova Scotian slope.

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