CLOV PROJECT DEEPWATER TECHNOLOGY, HUMAN EXPERTISE
Participating in Angola deepwater resources development CLOV is the fourth deepwater development on Angola’s prolific Block 17 operated by Total, following Girassol, Dalia and Pazflor. The fields lay 140 km north-west of Luanda in water up to 1,400 metres deep with a cumulative development area of 381 km2. CLOV is an FPSO-based development. Associated gas will be piped ashore to a LNG plant and produced water will be re-injected to maintain reservoir pressure. The overall area is expected to produce about 505 Mb of oil over twenty years, three-quarters of it high-quality Oligocene oil and one quarter lower-quality Miocene oil. First oil is planned for Q2 2014.
THE CLOV STORY: FROM DISCOVERY TO SANCTION
block 17 ATLANTIC OCEAN
block 15
CLOV is the acronym for four fields: Cravo, Lirio, Orquidea and Violeta. At first there was just Lirio (discovered 1998), a promising Oligocene field with a large gas cap, and then Cravo (1999, Oligocene again). Subsurface studies and new reservoir models soon indicated reserves larger than estimated. With two new discoveries, Orquidea (1999) and Violeta (2001), the concept crystallised as a hub based on Cravo-Lirio and future tie-back development of the two Miocene accumulations (Orquidea-Violeta Central) as well as the Oligocene reservoirs (Orquidea 11 West).
ANGOLA
• SOYO
block 1
block 2
block 31 block 16
block 3
• NZETO
block 32 block 4
block 17
• NZETO
block 33
By February 2007, CLOV was officially a Project. Gas was to be partially re-injected into Lirio during the first years and later exported to the AnLNG plant (Soyo). But a sharp rise in industry costs during 2007 led to a cost optimisation exercise and a new concept: full gas export to AnLNG, re-injection elsewhere in Block 17 as a fall-back solution, and a single production ring on Cravo-Lirio to replace the original dual line concept. Basic Engineering began at the end of 2008. Again to control costs, the contractual process included innovative strategies to split packages and encourage more competition between contractors.
block 18 block 5
block 34 block 19
Conceptual studies were launched in March 2005 to select the best option (subsea architecture, process design, type of floating support, etc.). Pre-Project phase, which started in early 2006, integrated 3G evaluations of Orquidea and Violeta and results of two new appraisal wells (Orquidea-2 and Violeta-2). At this stage thoughts turned to a stand-alone development.
• LUANDA
block 17
The CLOV Project was sanctioned in July 2010 and key contracts were awarded soon afterwards.
ZINIA Oligocene field Miocene field
TIMELINE
> STAKEHOLDERS CONCESSIONAIRE
1998
CONTRACTOR GROUP
Operator 40%
23,33%
20%
16,67%
> MAIN CONTRACTORS FLOATING PRODUCTION, STORAGE AND OFFLOADING (FPSO)
SUBSEA UMBILICALS, RISERS AND FLOWLINES (SURF)
MULTIPHASE PUMPS (MPP)
OFFLOADING SYSTEM (OLS)
SUBSEA PRODUCTION SYSTEM (SPS)
Discovery of Lirio
1999 Discovery of Cravo and Orquidea
2001 Discovery of Violeta
Q3 /2010 Project sanction
Q2 /2011 Start of fabrication of FPSO components at the Paenal yard in Angola
Q3 /2011 Start of FPSO hull construction in Korea
Q2 /2012 Start of the first subsea installation campaign
Q3 /2012 Start of the drilling campaign
Q3 /2013 Arrival of the FPSO at the Paenal yard in Angola
Q4 /2013 Arrival of the FPSO on site
Q2 /2014 First oil
Q3 /2016 End of the development drilling campaign
HSE
STRIVING FOR EXCELLENCE
Excellence in Health, Safety and Environment (HSE) performance is the top priority for CLOV. HSE objectives are: • To ensure that no harm comes to people or facilities (zero accident) • To provide healthy workplaces • To minimize environmental impact such as emissions and discharge • To make sure contractors apply Total’s high HSE standards.
FOCUSING ON SAFETY HSE priorities are applied at all stages of the project.
During the selection of contractors HSE is built into the Call for Tender specifications, proven HSE performance is an important factor in choosing contractors and their facilities. HSE Management Systems are therefore audited beforehand. During construction and installation, Total carries out audits and inspections to ensure that contractors comply with requirements. Emphasis is placed on training and on incident/near-miss reporting and follow-up. Total construction specialists are also present on all sites to provide guidance. As first oil nears, detailed procedures and trained operators are an essential requirement for the start-up and field operation phases. Top priority is safety, for Total personnel as well as contractor employees.
GG&R
Geology, Geophysics & Reservoirs PRODUCING OLIGOCENE AND MIOCENE RESERVES TOGETHER The Project is developing both Oligocene and Miocene reservoirs, which lie at different depths and so involve different temperatures and pressures as well as different oils. Moreover, the Oligocene Orquidea 11 West (O11W) reservoir lies beneath the Orquidea and Violeta Miocene reservoirs. Oligocene reservoirs account for three quarters of CLOV’s oil. They are older and less permeable than the Miocene reservoirs but the oil is lighter and among the highest quality on Block 17. Miocene reservoirs account for the rest of the reserves. They are younger and offer better permeability than the Oligocene reservoirs but the oil is more viscous and lower quality. The unconsolidated turbidite sand reservoirs found on CLOV are typical of Block 17, so the Geophysics teams can leverage the extensive knowledge Total has gained during previous projects. But four separate fields with Oligocene and Miocene reservoirs naturally involve differences: consolidation, permeability, pressure, fluid viscosity, target accessibility. The context ranges from the ‘easy’ Lirio pattern of thick and productive channelized reservoirs sometimes one above the other, to the more challenging Cravo reservoirs made up of extensive, thin, heterogeneous sheets. These result in smaller targets, lower seismic definition and increased uncertainty about vertical connectivity and compartmentalisation. CLOV brings unusual challenges too. Due to the superposition of the Oquidea-Violeta Miocene field above the 011 West Oligocene field, the seismic signal can be partially absorbed by the upper reservoirs. In addition, O11W has a 15°-20° dip. Both of these factors contribute to poor seismic images and greater uncertainty in terms of drilling objectives and well positioning. The other major challenge is that Lirio has a sizeable gas cap above the oil layer, requiring selective completions to control the amount of gas produced without slowing the flow of oil and impacting plateau production.
WELLS
Lirio field with the gas cap (gas in red)
OLIGOCENE Cravo, Lirio & O11 W
MIOCENE Orquidea-Violeta Central
• 26 million years old • 3/4 of total reserves • Reservoir depth ~2,830 m MSL • Reservoir pressure ~300 bar • Temperature ~75 to 80°C • Low viscosity ~0,6 to 0,7 cp • High quality oil (32° to 35° API) • Gas-oil ratio ~170 v/v for Cravo and O11W and 150 to 1300 v/v for Lirio
• 17 million years old • 1/4 of total reserves • Reservoir depth ~2,100 m MSL • Reservoir pressure ~200 bar • Temperature ~50°C • High viscosity ~1 to 6 cp • Quality oil (20 to 32° API) • Gas-oil ratio 72 to 120 v/v
2 DRILL-SHIPS, 34 WELLS, MORE THAN 2,000 DAYS
CLOV will require 19 oil production wells and 15 water injection wells. 32 of the 34 wells will be horizontal, with maximum drain length of 1,800 m and maximum horizontal departure of 2,600 m. The other two wells will be deviated, i.e. less than 65° off vertical. Average reservoir burial depth is about 1,000 m for Miocene and 1,500 m for Oligocene. DRILLING SCHEDULE Drilling is scheduled to start in Q3 2012. One drill-ship, Pride Africa, will start immediately and be joined by West Gemini in Q1 2013. Both vessels have dynamic positioning and West Gemini, a new-build, has two derricks which can reduce the
“time-per-well”. Fifteen wells will have to be drilled, completed and connected by first oil in Q2 2014: four injectors (1 on each field) and eleven producers. Overall drilling time will be more than 2,000 days for the 34 wells. As CLOV wells have to cross multiple small/ thin reservoirs with restricted tolerances and the presence of faults, two deviated wells will be drilled early to help calibrate vertical uncertainties and plan subsequent horizontal wells.
West Gemini, one of the two drill-ship © Seadrill
ARCHITECTURE AND SAND CONTROL Well architecture is standard for Block 17. Most wells need only standard light architecture. Only nine wells require heavy architecture, with intermediate casing. Sand production is a concern on all four fields. The current sand control design requires 12 of the 19 producers and all injectors to have a stand-alone screen (natural sand packing) and the seven deviated producers will have open-hole gravel pack (artificial packing). 7 of the 32 wells will have selective completions: 5 oil producers (for production and gas management reasons, particularly because of the Lirio gas cap) and 2 water injectors.
SPS
SUBSEA PRODUCTION SYSTEM
SURF
SUBSEA UMBILICALS RISERS & FLOWLINES
CRAVO-LIRIO
CRAVO-LIRIO
• 19 wells
• 17 km production ring of 12”/16” pipe-in-pipe
(10 producers, 9 water injectors)
• four 4 – slot 12’’ manifolds ORQUIDEA-VIOLETA • 15 wells (9 producers, 6 water injectors)
• four 4 – slot 10’’ manifolds • Multiphase Pump System (2 helico axial pumps – 1 in back up)
• Tie-in and tooling systems for connections to manifolds and Xmas trees • Installation and Work-Over Control System for 2 drilling rigs • Subsea production control system, including fibre-optics.
• 2 water injection lines (24 km of 12”) • 1 Hybrid Riser Tower for production (12’’/16’’) and water injection (12’’) with riser bottom gas lift ORQUIDEA-VIOLETA • 21 km of production lines of 10”/14” pipe-in-pipe, comprising 14.5 km of dual flowline and 6.5 km of single flowline in a mini-ring, for commingled Miocene and Oligocene oils • 2 water injection lines (33 km of 10”) • 1 Hybrid Riser Tower for production (10”/14”) and water injection (10’’) with riser bottom gas lift 84 km of umbilicals (combined production and water injection)
GAS EXPORT • 32 km of 12’’ pipeline to PLEM 17 b/c for gas export to Angola LNG tie-in point
FPSO
FLOATING PRODUCTION STORAGE & OFFLOADING
• Hull dimensions: 305 m x 61 m x 32 m • Purpose-built double-sided hull with single bottom, spread moored in 1,291 m water depth • Single train process and storage for commingled Oligocene and Miocene crude oils
WELLS • 34 wells will be drilled (15 wells at the first oil) with 2 deepwater dynamic positioning rigs: West Geminii and Pride Africa. • Overall drilling time: more than 2,000 days
• Oil production capacity: 160 000 b/d at plateau • Oil storage capacity: 1.78 Mb • Process for oil and water separation based on wash tanks, settling tanks and oil desalting • Topsides weight: approx. 34,000 t (dry weight) • 11 topside modules • Water injection capacity: 319 000 bw/d
Offloading System
• Gas treatment compression capacity: 6.5 Msm3/d • Compact water treatment units (2 technologies Ultra Filtration & Minox) • Living quarters capacity: max 240 persons on board.
• Single Hybrid Riser (12.75’’) OLS (OFFLOADING SYSTEM) • Oil Loading Terminal (OLT): 18 m of diameter, 17 m high, moored about one nautical mile (1.852 km) from the FPSO • 2 Oil Offloading Lines (OOL): 24’’ pipeline, 2 km long
Multiphase Pumps
Water injection Production pipe-in-pipe Gas lift
• Fibre Optic Cable (FOC) to carry data communication between the FPSO and the buoy.
Hybrid Riser Tower sight cutting
A tried and tested concept for optimum production
CLOV PROJECT • First oil: Q2 2014 • Reserves at 20 years production duration: 505 Mb • Oil production capacity: 160 kb/d at plateau • Liquid treatment capacity: 229 kb/d
FPSO
ALL-ELECTRIC FPSO WITH VARIABLE SPEED DRIVE FOR ENERGY EFFICIENCY CLOV is Total’s second all-electric FPSO but the first to benefit from Variable Speed Drive (VSD). All the rotating machinery is driven by electric motors.
CLOV specifics MPP
SUBSEA MULTIPHASE PUMPS, A FIRST FOR TOTAL
Until recently, big FPSO machinery was driven by gas turbines. While smaller machines were driven by electric motors, either LV (Low Voltage) or HV (High Voltage), fed by LV or HV generators. CLOV’s all-electric FPSO has 3(+1) large aero-derivative gas turbo-generators that produce all the power it needs. The advantages are: • Improved availability (less maintenance at longer intervals than gas turbines) • Networked generators for less energy waste • More economical (CAPEX and OPEX) and rotating packages take up less space • Reduced environmental footprint (larger generators are more energy-efficient). The VSD technology, a first for Total on a FPSO, allows operators to vary the frequency, and therefore the speed, of large machines such as compressors and water injection pumps, which was previously impossible. VSD helps to optimise energy consumption and operating costs.
Weight : 28 t / ΔP : 45bars / Gas Volume Fraction : 53% (Miocene year 15) / Shaft power : 1.8 MW
CLOV is the first time Total will use helico axial subsea MPP. The MPP system will be positioned on the seabed, at a water depth of 1,170 m and will include two pumps (one as back-up). They are installed on Orquidea-Violeta, where reservoir pressure is lower and oil viscosity higher, to boost the flow pressure later in field-life to ensure optimum oil recovery. The pumps are customized to CLOV reservoir conditions (about 40% gas) and have to operate at different speeds depending on the composition of the fluid, so they include a control module linked by umbilical to the FPSO, which can activate a Variable Speed Drive. And the biggest challenge? The pumps need 6,6 KV electrical power supply and are in water, so the challenge is to get the power to the pump and to insulate the motor. The advantages of MPPs: • Produce low-pressure reservoirs • Improve recovery (when production declines because of falling reservoir pressure, MPPs can extract more oil) • Reduce costs (MPPs significantly reduce flow-line loops) • Make greater pressure drops possible before oil-gas separation.
FPSO
WASH TANKS IN THE HULL: A FIRST FOR BLOCK 17
Another characteristic is the wash tank technique for oil-water separation. The FPSO has two wash tanks in parallel inside the hull, each the size of a tennis court (507 m2) and 32 m high. After gas separation, the production fluids are then routed via a static mixer to the wash tanks for separation. Wash water is added upstream of the static mixer ensuring that the watercut is sufficient to promote effective coalescence of water droplets before the production fluids enter the wash tanks. The tank provides significant residence time for oil-water separation.
Oil separated in the wash tanks is pumped under liquid level control by the oil transfer pumps to the cargo tanks via the loading header. Oil may also be routed to the continuous settling tank if further oil/water separation is necessary or if crude washing is required to meet the export oil-salt specification. The main Wash tank advantages are: • Reducing the scope and weight of the topsides • Minimising the risk of naphtenate deposition.
LOCAL CONTENT TAKING ANGOLAN CONTENT TO A NEW LEVEL Total is committed to develop Angola’s human and industrial capabilities by prioritising local content. CLOV has raised the bar higher than ever before. FPSO The FPSO will account for 7,700 t of local fabrication, including a 2,335-t topsides module. FPSO topsides module locally fabricated, for the first time, will be integrated in Angola as well as other FPSO elements (side protector). This work will be performed at the Paenal yard in Porto Amboim. SURF The Sonamet yard at Lobito is handling about 40,000 t of fabrication and assembly: OLT buoy, bundled risers, well jumpers, production and water-injection lines and spools (pipe-in-pipe, all double jointing, and some coating), suction anchors, SIV modules, and buoyancy tanks. The umbilicals are being fabricated by the Angoflex yard in Lobito. SPS 7 out of 8 manifolds will be fabricated in Angola, along with support structures and foundations including the MPP foundations. Xmas-trees will be delivered to Angola 75% complete, the rest will be assembled and tested in-country. 19 wellhead housings will be machined in Angola and 34 of the 36 permanent guide bases will be fabricated locally.
LOCAL CONTENT OBJECTIVES Maximize work in-country • 9 million man-hours of work in Angola • 64,000 t of fabrication and assembly (7,700 t for the FPSO) • 20% of the global cost of the project for local fabrication and assembly • Nearly 60% of the SURF package (by volume). Include Angolans in CLOV and contractor management teams • Project Management Team Angolanisation plan implemented with TEP Angola. Promote human and industrial capacity building • Use of local firms a major factor in contract awards • Contractors required to set up training programmes. Management-level Local Content Coordinator from the planning stage. stage
Paenal Yard
ENHANCING HUMAN RESOURCES AND INFRASTRUCTURES Total has a long-term vision of local content, a broad human and industrial approach designed to build up human resources and infrastructures and ensure that Angolans are trained and equipped to play a more decisive role in future projects. A growing number of Angolan personnel are joining the Project Team, including at managerial level. Many local engineers and technicians will be gaining valuable experience and skills while working on the Project. Infrastructure development related to CLOV includes: • The Paenal yard in Porto Amboim, which is being greatly expanded to be able to perform fabrication and integration (extension of the quay from 80 m to 420 m, extension of the breakwater to 530 m with 430 m fully stabilized, dredging of the port, quayside fabrication zone, cranes, workshops, offices). • The Angoflex yard in Lobito, which is undergoing a significant upgrade to boost capacity by about 50% and enable the facility to make longer sections of umbilical and so minimise the number of connections.
ADOPT, ADHERE, ADAPT ‘The best way to meet the challenge of local content is to take a positive approach. Total E&P Angola is committing to a worthwhile cause. Our motto is: adopt, adhere, adapt.’ Project Director Geneviève Mouillerat
Texts : Graham Lord - Agency : Enjoy Artco (Stéphanie Vernier, Pauline de Bast, Katia Berlioz & Laurence Parlouer) - Illustrations : Estech-design (Bruno Sommier, Julien Klejtman), Seadrill, Bip Info - Photos : Thierry Gonzalez, Getty Images - © Total E&P Angola – July 2011
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