YoungPetro - 12th Issue - Summer 2014

SUMMER / 2014

E ditor’s Letter

3

Dear Readers, I am delighted to introduce the first YoungPetro issue prepared by new editorial board. We are accustomed to changes, they are necessary. This year came time for changes in YoungPetro. With this words, I would like to say big THANK YOU to previous editor-in-chief, Michał Turek and his deputy, Jan Wypijewski for their great effort and the work which they put into YoungPetro, to develop the project and make it better and better with every issue. I hope that you will appreciate the new staff.

All students are due to finish the academic year, which was a time of hard work as well as taking ambitious challenges. The first half of 2014 year was full of really interesting student petroleum events, which showed the whole world the power

of young generation and put faith into the future of our industry. You can read about some of the events in this issue. I would like to draw your special attention to the article about the 5th edition of “East meets West” Congress, which took place in Krakow in April.

The following months will be also very important.

This will be not only a vacation time, but also a time of summer internships. You will have a wonderful opportunity to gain a practical view of being an employee of the E&P companies and to acquire new skills which are unavailable during university classes. You will find interesting articles about the theme in the next, autumn issue of YoungPetro.

Have a great summer, definitely with YoungPetro!

SUMmer / 2014

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Editor-in-Chief Joanna Wilaszek j.wilaszek@youngpetro.org Deputy Editor-in-Chief Maciej Wawrzkowicz m.wawrzkowicz@youngpetro.org Art Marek Nogieć www.nogiec.org Editors Kamil Irnazarow Edyta Stopyra Science Advisor Ewa Knapik Tomasz Włodek Proof-readers Paweł Gąsiorowski Urszula Łyszczarz Aleksandra Piotrowska IT Michał Solarz

issn

2300-1259

Published by An Official Publication of

The Society of Petroleum Engineers Student Chapter P o l a n d • www.spe.net.pl

Logistics Radosław Budzowski Marketing Barbara Pach Ambassadors Alexander Scherff – Germany Tarun Agarwal – India Mostafa Ahmed – Egypt Jin Ali – Russia Manjesh Banawara – Canada Rakip Belishaku – Albania Camilo Andres Guerrero – Colombia Filip Krunic – Croatia Moshin Khan – Turkey Mehwish Khanam – Pakistan Viorica Sîrghii – Romania Michail Niarchos – Greece Rohit Pal – India Publisher Fundacja Wiertnictwo - Nafta - Gaz, Nauka i Tradycje Al. Adama Mickiewicza 30/A4 30 - 059 Kraków, Poland www.nafta.agh.edu.pl

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A Little Bit More about Shale Gas 10 Hubert Karoń

Importance of Porosity-Permeability Relationship 14 and Its Use in Commercial Software Reza Kazmi, Jawad Sarmad

Methods of Predicting the Liquid Loading – Comparison 23 Hafiz Muhammad Haleem-ud-din Farooqui, Marium Altaf

A Novel Methodology for the Construction 29 of Homogeneous Synthetic Sandstone Cores Hernando Buendía Lombana, Juan Carlos Lizcano Niño, Robert Eduardo Padrón García

EOR Evaluation Using Artificial Neural Network 35 Steffones K, Abhishek Tyagi, Akul Narang

System which Rules South-Eastern 40 Europe – Russian Gas Pipelines Radosław Budzowski

Five Years of a Great Experience! 45 Joanna Wilaszek

The Annual Student Energy Coneference 2014 49 Filip Krunić

In the Blink of an Eye 51 Jan Wypijewski

Pages from a Diary: India 53 Rohit Pal

How it works? 56 Maciej Wawrzkowicz

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On Stream – Latest News Radosław Budzowski

Green oil – is it real?

Russia began extracting oil in the Arctic

In nature the process of oil formation takes millions of years and there are concerns that we consume it too quickly. Researchers at the Pacific Northwest National Laboratory have discovered how to shorten the process to just a few minutes, cutting costs at the same time.

In mid-April, Russia began to extract oil from the bottom of the Barents Sea. It is extracted on a Prirazlomnaya platform, which is the first Arctic-class ice-resistant oil platform in the world, designed to operate in extreme weather conditions that can resist maximum ice load.

It carries out all technological operations including: drilling, production, storage, preparation and loading of oil. "The start of loading of the oil produced at Prirazlomnaya means that the entire project will exert a most encouraging influence on Russia’s presence on the energy markets and will stimulate the Russian economy in general and its energy sector in particular," said Vladimir Putin, Russian President. A total of 300,000 metric tons are planned to be exported to international markets through Rotterdam port in 2014. For this purpose, a pool of oil purchases is being formed for the oil to be on sale with a price discount to Urals oil price. At first, oil will be sold through a spot scheme to oil refineries in the Netherlands, Norway and Great Britain. Gazprom Neft plans to use a storage facility in the future to optimize oil export supplies.

The developed technology involves pumping of a slurry from wet algae to a reactor where at a temperature of 350 degrees Celsius and a pressure of 3,000 psi occur processes of hydrothermal liquefaction and catalytic gasification.

The result is unprocessed petroleum, which can be further refined into fuel, clean water and other substances (such as nitrogen, phosphorus and potassium) as well as gas – which can also be used to generate electricity or, after being compressed, even to power cars. “Not having to dry the algae is a big win in this process, that cuts the cost a great deal,” said D. Elliott, a researcher at the PNNL. As the calculations show, in this process about 50% to 70% of the carbon contained in the algae can be converted into natural hydrocarbons.

The only downside of this new solution is the cost of creating a high-pressure and high-temperature reactor which, in the final analysis, should be returned very quickly, all the same. The new technology can enter the market soon, because the license for its use has been purchased by an American company Genifuel Corp., which is working on the construction of a prototype "algal-refinery" acting on an industrial scale.

In September 2013, a group of Greenpeace activists protested against the opening of the platform. Activists claimed that the platform does not have adequate safeguards in the event of an oil spill. They pointed out that any failure could lead to serious contamination of the Arctic. Russian experts had a different opinion. They argued that the device has the latest security systems.

Russian border guards arrested protesting environmentalists and the government accused them of piracy. The investigation was waived under the amnesty. 

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International Student Petroleum Congress & Career Expo 6th Edition, 22nd - 24th IV 2015 Krakow, AGH UST

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ďťż

Find us on Facebook facebook.com/YoungPetro

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For online version of the magazine and news visit us at youngpetro.org

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A Little Bit More about Shale Gas

interview | with Jacek Trojanowski

A Little Bit More about Shale Gas Hubert Karoń Jacek Trojanowski, M.Sc. – Geophysicist, former Seismic Monitoring Team Leader; Polish Academy of Science.

YP: Can you tell us about your first job experience? Later on, what did convince you to work for Polish Academy of Science?

YoungPetro: Before you became Geophysicist in Department of Geophysical Monitoring of Polish Academy of Science you had graduated from the Faculty of Physics, Warsaw University. When did you realize that you would be working as a Geophysicist?

JT: To be honest, it was quite strange to work for a big public institution after my previous experience in small private enterprises. Completely different type of job if you know what I mean. But I got used to it.

Jacek Trojanowski: The first step was a decision to make Master’s thesis in geophysics, but in the meantime I tried different jobs, completely not related to geophysics or even physics. After graduation I got a proposal to work in the Institute of Geophysics, Polish Academy of Sciences which eventually turned me to become a geophysicist.

Anyway, the job was an opportunity and challenging because I was appointed to lead a team responsible for establishing completely new seismic project. Additional value was a free way to develop in research.

YP: Shale gas in Poland is a very hot topic. Do you make any research connected with this topic?

Hubert Karoń

JT: At the beginning of the excitement about shale gas in Poland, I noticed that microseismic monitoring is conducted during the process of hydraulic fracturing and that there may be a room for my Institute and my team to provide seismic monitoring. Indeed some time later, we monitored the site of Lebien LE-2H during the first ever hydraulic fracturing treatment conducted in Poland.

Since then, I have been focusing my interest and research on microseismic monitoring, specifically on getting as much information about an event as possible from the signal of very low signal-tonoise ratio.

YP: Some people say hydraulic fracturing may be very dangerous to the environment and our health. What are the real threats that we should be concerned about?

JT: Well, it is a very delicate matter. You can’t definitely say that there is no risk at all, because you need to prove it, but environmentalists who blame hydro-fracking for every evil thing in the world should prove it too. I think that it is time for collecting evidences – scientific facts and by now I have seen more positive studies than negative ones. Of course, there are always some examples of failures or mishandling but remember that there are hundreds of thousands wells drilled in the US and Canada which were made correctly. After all, there is hardly any industrial activity which does not have any impact on environment. The task is to reduce this impact. Shale gas has changed the US industry into a competitive one and also changed a political position of the US which is not as much related to oil and gas suppliers as it used to be. I believe that there are reasonable means of control of sustainable and safe shale gas exploration.

YP: Should we be worried about destabilization of the natural distribution of strain in the Earth’s crust?

JT: I do not think we are able to do it. We can have influence on a very limited amount of rock which – in the worst case – can reactivate some existing natural faults but on very limited scale. I think that

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a Blackpool case is one of the worst cases we can expect. Technically negligible effect but social impact can be large. At this point I must remark one important difference between Poland and the US. It is common in the US to inject produced water into disposal wells whereas in Poland chemical methods are rather used to utilize produced water. There are much bigger amounts of water injected into disposal wells than it is during hydraulic stimulation which makes much bigger potential influence of disposal wells on seismicity level than hydraulic fracturing.

YP: It is common to monitor microseismicity induced during hydraulic fracturing. What type of seismic methods are used in this process?

How big are detected events?

JT: It is not as common as one could expect. The exact figures are not known, but I saw some rough assessments that a few percent of hydro-frac jobs are monitored which makes a room for further development. The problem is that seismic monitoring is relatively expensive and not all operators are convinced to use it. The most popular way is to put a vertical seismic array in one borehole to monitor the other one where treatment is conducted. It gives high number of detected events because receivers are very close to events, however, the cost of drilling a monitoring well rapidly rises with its depth which in Poland may reach as far as 4,000 m. What is more, result of such monitoring suffers from poor azimuthal coverage which harms location of events and their mechanism determination. Another option is to monitor from the surface, but seismic signal of small events is very weak and is hidden by high amplitude surface noise. Typical microseismic events induced during fracking have magnitudes below 0, whereas earthquakes have magnitudes about 3, magnitudes 5 can cause some damages, 7 – serious damages, 8 – are devastating. The largest earthquake ever had magnitude 9.5 (Chile, 1960). In terms of the released energy, a difference of two magnitude degrees is 1,000 difference in energy. The smallest events recorded downhole release seismic energy as small as a rock sample crack in a lab. To retrieve very weak signal recorded on the surface it is necessary to use thousands of receivers and migra-

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A Little Bit More about Shale Gas

tion methods known from seismic imaging. After stacking many traces some events become visible.

Using surface measurements you can better resolve source mechanism and – in this way – supplement information about processes occurring during hydro-fracturing. Different mechanisms may indicate different fracture systems or show natural faults reactivation.

seismic hazard is related to geothermal sites where much bigger amounts of water are pumped into the ground, which influences natural equilibrium much more than smaller amounts of water used during hydraulic fracturing. What’s more, some geothermal sites are hydraulically stimulated too, but there are no eco-activists requesting of their shutdown. Don’t you see any contradiction?

Both information are important for a job being conducted and for planning next jobs.

YP: Optimists pin their hope on Polish shale, but at the same time there are protests against hydraulic fracturing. What do you think about the future of Polish gas industry? Is it possible for Poland to become natural gas exporter?

YP: Could you compare this events with other earthquakes caused by human activity (e.g. coal mining)?

JT: The scale of induced seismicity depends on local stress and rock’s type. In Poland, induced seismicity is relatively high and many Upper Silesia residents know the feeling of seismic tremors.

Even bigger events are induced in Legnicko-Glogowski Copper Mine Region, Lower Silesia, Poland where some of the events are comparable with small earthquakes. Is that a reason to stop exploration? No. If you do not believe, just ask people whether to close all mines in their region or not. I can foresee the results. There should be defined rules to compensate any losses related to mining activity, but it is a public interest to keep exploration. In comparison to seismicity induced by mines events induced by hydraulic fracturing are very small and hardly ever can be felt. It is a pity that during first attempts in Europe one relatively large event was induced in Blackpool, England in 2011.

It was strong enough to be felt and it was new experience for British people because there is very small induced seismicity and natural seismicity is small too. This accident was caused by pumping water into preexisting natural fault with accumulated stress. Probably operator could have prevented this event form appearing by conducting microseismic monitoring and appropriate safety procedures. It is a lesson for the future at the cost of two-year-long brake in developments in the whole Britain and much worse atmosphere about shale gas in Europe than it could be. Much bigger

JT: Moods have been changing from the euphoria, as at the beginning, to gloom after retreating some big companies from Poland but the future remains unknown as unknown are our shale gas resources.

Time will tell.

YP: Have you seen movies “Gasland” and “Fracknation”? What is your opinion about them?

JT: Yes, of course, I am really disappointed with high popularity of “Gasland”. I do not understand how fiction can be called a document. Those who like its point that it is an artistic point of view on a very important problem and doesn’t need to be strict. Yes, but why they call it a document? Josh Fox, an author of “Gasland”, is an eco-activist, who strongly believes in what he does which, in his opinion, justifies any means he undertakes, even lying. “Fracknation” is a natural response to “Gasland”. The author engages on the other side and is tracking Fox’s lies.

The only good thing of the whole mess done by “Gasland” is that Oil & Gas companies put more attention to environment and dialog with local societies. Since the problem started to be discussed in public, many efforts, at both sides, are made to ensure everybody that fracking is OK or nasty (dependently on the side engaged).

I hope that this public discussion will reveal facts and reduce prejudices.

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Hubert Karoń

YP: What do you think is the key to success?

Do you have any advice for our readers how to survive and not freak out in the Petroleum Industry?

sion based on facts. I hope that people will get used to this new technology.

JT: I think that we need a lot of patience to explain everything and to make people trust in this new technology.

JT: In the near future I want to finish my Ph.D. on microseismicity and then I want to continue my research in this very interesting and quickly developing field. Hopefully, with a good cooperation with the industry which should understand that research is a key do develop in new fields.

The second most important thing is transparency of technical details, especially those related to common concerns like composition of fracturing fluids or ways of production water utilization.

Any hidden fact will be used by opponents. It is not only a matter of the industry but also politicians, journalists and scientists to hold discus-

YP: What are your plans for the future?

YP: Thank you very much for the conversation and we wish you more successes.

JT: Thank you very much.

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··

Importance of Porosity-Permeability Relationship and Its Use in Commercial Software

Importance of Porosity-Permeability Relationship and Its Use in Commercial Software Reza Kazmi, Jawad Sarmad

Porosity and permeability are considered to be very import ant parameters for petro-physical evaluation of sedimentary rocks. Porosity is the formations’ ability to store the hydrocarbons, while permeability is the rocks’ ability to conduit the fluid. Porosity and permeability can be measured experimentally or calculated using established empirical correlations in the absence of the core data. Experimental data for porosity and permeability from the exploratory well of XYZ field; will be used to develop a correlation between porosity and permeability of XYZ field.

The developed correlation can be used to calculate permeability by using log – porosity values at different depths during the fields’ development to cut down the coring expenses. Moreover, more prominent objective will be achieved by knowing that relationship existing either in consolidated/unconsolidated sandstone or in both. The results of porosity – permeability correlation will be used in commercial software ‘SENDRA’ to get the capillary pressure and relative permeability data which mark the utilization of correlation.

Introduction During the formation evaluation, the most important properties taking under the consideration are its porosity and permeability. Porosity governs the storage capacity and permeability deals with the transmission of fluids through porous medium [3]. Porosity can be measured through core samples in the laboratory and well logs at the field but permeability determination near well bore is usually done with the help of coring and other techniques. These properties are significant for res-

**Univ. of Engineering and Technology Lahore ÞÞPakistan smrkazmi5@gmail.com jawadsarmad@yahoo.com  University  Country  E-mail

ervoir effectiveness evaluation and development program formation [19]. A highly porous rock, which has enough void volume to store hydrocarbons but does not have large pore throat sizes that could accommodate an easy fluid flow is never exploited. This shows that porosity and permeability relationship may not always be linear. Generally, in consolidated sandstones logarithm of permeability is often directly proportional to the porosity, whereas in sands, when grain sizes increases, permeability might increase with a decrease in porosity [14]. Thus, their significance demands on accurate determination of these parameters for better prediction of the reservoir potential.

A strong relationship thus exists between these two rock properties which may vary depending on different conditions, which different reservoirs are subjected. Coring is considered to be an expensive job during rock evaluation do getting core samples from every development well is not practically feasible. This is why, numbers of models are utilized for predicting permeability based on different rock characteristics such as grain size, pore geometry, surface area, porosity etc. Other than this models that directly using well log measurements is also used for this. [14].

Pores of the reservoirs are generally not only filled with one type of fluid. Thus, due to this presence of different immiscible fluids, they exert a capillary pressure on their interface depending upon

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Reza Kazmi, Jawad Sarmad

1000.0

100.0

Permeability, mD

10.0

1.0

0.1

0.0 1.0

10.0

100.0

Porosity, %

Fig. 1 – Porosity Permeability Relationship in Sandstone

type of fluid, pore geometry, and the movement ability of different fluids is interdependent upon each others’ saturation and wetting or non-wetting characteristic. This is known as a relative permeability [5,8].

Methodology The following methodology is proposed to accomplish objectives after getting data.

The procedure adopted by company on the entire data pertaining to work was collected from XYZ field. This data comes from a core plug which is 2 ½ inch thick and 26.52 m long from an explor-

atory well at depth from 3,331.84 m to 3,358.36 m.

The retrieved core was divided into 56 small cores for experimental measurements of porosity, permeability and capillary pressure. For this, experimental results of porosity and permeability were obtained from an exploratory well of XYZ field.

These values were plotted on x-y plane to draw a graph between them and develop correlation.

This correlation enables to calculate permeability values through this developed correlation by inserting log porosity values instead of carrying out further experiments for each developing well.

Using ø-k data, the power trend correlation was developed which has been checked to calculate “k” by using porosity of core plug. The calculated porosity and permeability were averaged using

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Importance of Porosity-Permeability Relationship and Its Use in Commercial Software

the formulas as mentioned in Appendix B. Also by utilizing capillary pressure data and end points data of gas – water system were used to generate pc and kr curves using LET and Burdine correlations available in SENDRA and results were simulated.

Result Analysis In this section, experimental values of porosity and permeability were used to develop a mathematical model. Experimental value of average porosity was used to calculate permeability from the developed equation for validation of results. In the last part of this paper, capillary pressure and relative permeability curves were generated through commercial software SENDRA by using average porosity and permeability values from experimental data along with data requires in the software.

Input data The necessary experimental data used to execute the experimentation at XYZ company as can be seen in the Table 1:

Sr No.

Parameters

Value

1

Thickness (m)

26.52

2

Avg. Porosity (%)

11.3

3

Avg. Permeability (mD)

20.28

4

Density of gas (g/cm3)

0.5

5

Viscosity of gas (cP)

0.020

6

Density of water (g/cm )

1.2

7

Viscosity of water (cP)

0.36

8

Irreducible water saturation (%)

10

9

Initial water saturation (%)

10

3

10

Initial gas saturation (%)

0

11

Residual gas saturation (%)

15

12

Pore size distribution index (–)

5

13

Displacement pressure (psi)

10

14

Immobile oil saturation (%)

15

From these scattered points it can be inferred that relationship between two parameters is supporting unconsolidated behavior as log-log graph of porosity and permeability is mostly a straight line for consolidated rock type. Actually, it is the cement and other digenetic materials inside the pores and pore throats that reduce the permeability as well as porosity of rocks. This does not mean that such materials will always decrease porosity too, along with permeability which is clear from the above figure, because points show samples having very high porosity but are at least permeable as can been seen in Fig. 1. The power trend was generated on scattered data points. This shows that porosity and permeability might not always have a linear relationship.

Y = 0.00017 X4.031

Average porosity value of 11.26% is used in it, which gives the approximate permeability value nearby to the actual permeability. Porosity and permeability relationship on log scale covers the entire range of our experimental observations shown in Fig. 1.

Capillary pressure and relative permeability curves are also important in reservoir evaluation.

These are obtained through experimentation on core samples. There are a certain built in correlations in SENDRA that are utilized in generating capillary pressure and relative permeability curves so averaged porosity and permeability values in SENDRA used to generate the capillary pressure using LET correlation and relative permeability curves using LET and Burdine correlations.

The process in which a non-wetting phase initially displaces the wetting phase is known as primary drainage as in Fig. 2, which shows that by increasing the pressure of non-wetting phase the saturation of wetting phase decreases. But there will be a point up to which non-wetting phase will continue to displace the wetting phase after which even after increasing capillary pressure the saturation would remain same. This is the connate water sat-

Reza Kazmi, Jawad Sarmad

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Fig. 2 – Primary Drainage Curve from LET Correlation

uration that is immobile and will not be able to flow no matter how greater the pressure might be applied.

LET primary drainage correlation was used for primary drainage capillary pressure curve. It includes a well define threshold pressure if required as shown in Fig. 3. Relative permeability depends upon the saturation as well as wetting characteristics of the rock. The LET correlation behaves rather flexible, smooth, and physical shaped curve of the relative permeability curves [21]. It can be observed that initial water saturation is approximately 10% and residual gas saturation is around 10%. This is because wetting phase occupies the smallest pores in the rock and thus finds it difficult to flow. Wetting phase requires a greater saturation to flow than non-wetting phase as it begins to flow at relatively lower saturation.

Fig. 4 shows the reverse process of drainage in which wetting phase displaces the non-wetting phase. The imbibition curve does not follow exactly the same path as that of drainage curve.

This is because as we change the saturation the relative permeability is changing and thus never remain the same to previous values. The correlation is symmetrical with the respect to the two fluids as neither of them dominates the wettability.

The strength of the LET-correlations for capillary pressure is that the saturation where the capillary pressure intersects the saturation axis and that the maximum and minimum capillary pressure can be set, and fixed.

Relative permeability depends upon saturation as well as wetting characteristics of the rock. It can be observed that initial water saturation is approximately 10% and residual gas saturation is

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Importance of Porosity-Permeability Relationship and Its Use in Commercial Software

Fig. 3 – Drainage Relative Permeability Curve from LET Correlation around 15%. This is because wetting phase occupies the smallest pores in the rock and thus finds it difficult to flow. Wetting phase requires a greater saturation to flow than non-wetting phase as it begins to flow at relatively lower saturation as can be seen in Fig. 5.

The process in which a non-wetting phase initially displaces the wetting phase is known as a primary drainage as in Fig. 2. The graph shows that by increasing the pressure of non-wetting phase the saturation of wetting phase decreases. But there will be a point up to which non-wetting phase will continue to displace the wetting phase after which even after increasing capillary pressure the saturation would remain the same. This is the connate water saturation that is immobile and will not be

able to flow, no matter how greater the pressure might be applied. LET primary drainage correlation was used for primary drainage capillary pressure curve. It includes a well define threshold pressure if required.

Fig. 4 shows the reverse process of drainage in which wetting phase displaces the non-wetting phase. The imbibition curve does not follow exactly the same path as that of drainage curve.

This is because as we change the saturation the relative permeability is changing and thus never remain the same to previous values. The correlation is symmetrical with respect to the two fluids as neither of them dominates the wettability.

The strength of the LET-correlations for capillary pressure is that the saturation where the capillary

Reza Kazmi, Jawad Sarmad

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Fig. 4 – Imbibition Capillary Pressure Curve from LET Correlation

Fig. 5 – Imbibition Relative Permeability Curve from BURDINE

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Importance of Porosity-Permeability Relationship and Its Use in Commercial Software

Fig. 6 – Matching of Experimental and Simulate Results

Fig. 7 – Simulate Results of Experimental Gas Production

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Reza Kazmi, Jawad Sarmad

pressure intersects the saturation axis and that the maximum and minimum capillary pressure can be set, and fixed. It can be observed that initial water saturation is approximately 10% and residual gas saturation is around 10%. This is because wetting phase occupies the smallest pores in the rock and thus finds it difficult to flow. Wetting phase requires a greater saturation to flow than non-wetting phase as it begins to flow at relatively lower saturation.

Appendix

Fig. 6–7 show experimental results of gas production, water injection which were simulated using the software, it shows very satisfactory results.

LET Drainage – Capillary

Conclusion

−

ÈÈ

ÈÈ

ÈÈ

ÈÈ

In consolidated formation, log-log plot between porosity and permeability is mostly a straight trend The developed correlation has limitation of porosity and permeability up to maximum value of 30% and 247 mD respectively Developed correlation gives satisfactory result for average value of permeability by using average porosity but not for scattered points The use of porosity and permeability are a necessary input to simulate the experimental output.

Average Porosity

∑(fi×hi) ∑(hi) Average Permeability

∑(ki×hi) ∑(hi) ( Ppcow − Ptpcow )(1− Swx)Lpow (1− Swx)Lpow + EpowSTpowwx

−

(1− Ftp)PtpcowSLtowwx SLtowwx + Etow(1− Swx)Ttow

tp + pcow

LET Imbibition – Capillary LET Imbibition – Rel krw0 (Sw * )

Lw

krw =

+ Ew (1− Sw * )

Tw

(Sw )

* Lw

Burdine – Rel 2+3/

krw = krw0 (Sw* )

2+/

krg = krg0 (1− Sw* ) (1−(1− Sw* )) 2

Sw − Swi 1− Swi − Sor

Recommendation

Sw* =

In the future, this study can be extended by using different correlations of capillary pressure and relative permeability, then by simulating the experimental injection production rate to find out which one fits better. 

Nomenclature ϕ – porosity h – thickness krw – relative permeability of water S*w – effective water saturation l – pore size distribution kro – relative permeability of oil k0ro – relative permeability of oil at 0% saturation

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Importance of Porosity-Permeability Relationship and Its Use in Commercial Software

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2. Ahmed, T. (3rd ed.). (2006). 3rd Edition Reservoir Engineering Handbook.

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4. Archie, G.E. (1950). Introduction to Petrophysics of Reservoir Rocks. Bulletin of the American Associates of Petroleum Geologists, 34(5), 943–961.

5. Average porosity. Oil Zone Tools. Retrieved September 19, 2013, from http://www.oilzonetools.com/ average_porosity.html 6. Berg, R.R. (1970). Method for Determining Permeability from Reservoir Rock Properties. Transactions. Gulf Coast Association of Geological Societies, 20.

7. Choho, T., & Pelce., V. (1989). A new method for Capillary Pressure and Relative Permeability Curve Matching for Gas/Water Flow. SPE Annual Technical Conference and Exhibition, San Antonio, TX. October 8–11, 1989.

8. Darcy, J.M. (2010). Core Tests for Relative Permeability of Unconventional Gas Reservoirs. SPE Annual Technical Conference and Exhibition, Florence, Italy. September 19–22, 2010.

9. Evans, C.E., & Guerrero, E.T. (1979). Theory and Application of Capillary Pressure. SPWLA 20th Annual Logging Symposium, Tulsa, OK. June 3–6, 1979.

10. Fuchtbauer, H. (1967). Influence of Different types of Digenesis on Sandstone Porosity. 7th World Petroleum Congress, Mexico City, Mexico. April 2–9, 1967.

11. Gang, T., & Kelkar, M.G. (2007). A More General Capillary Pressure Curve and Its Estimation from Production data. Rocky Mountain Oil & Gas Technology Symposium, Denver, CO. April 16–18, 2007.

12. Jiang-ming, D. (2013). Estimation of Porosity and Permeability from Conventional Logs in Tight Sandstone Reservoirs of North Ordos Basin. SPE paper No. 163953. SPE Unconventional Gas Conference and Exhibition, Muscat, Oman. January 28–30, 2013.

13. Katz., A.J., & Thompson, A.H. (1986). Quantitative Prediction of Permeability in Porous Rock. Physical Review B 34(11), 8179–8181.

14. Nelson, P.H. (1994). Permeability-Porosity Relationships in Sandstones. US Geological Survey, Denver, CO. 15. Paper, H., Clauser, Ch., & Iffland, J. (1998). Permeability Prediction for Reservoir Sandstones and basement rocks based on fractal pore space geometry. 1998 SEG Annual Meeting, New Orleans, LA. September 13–18, 1998.

16. Pittman, E.D. (1992). Relationship of Porosity and Permeability to various parameters derived from mercury injection Capillary Pressure Curves of Sandstones. AAPG Bulletin, 76. 191–198.

17. Schlumberger. (1988). Probing for Permeability: An Introduction to Measurements. The Technical Review.

18. Schneider, J.H. Ne Least square model used for development of Permeability-Porosity Correlation.

19. Tiab, D., & Donaldson, E.C. Theory and Practice of Measuring Reservoir Rock and Fluid Transport Properties.

20. Timur, A. (1968). An Investigation of Permeability Porosity, and Residual Water Saturation Relationships. The Log Analyst, 9(04).

21. Wetherford International. Manual of Sendra Software. 20B.

23

Hafiz Muhammad Haleem-ud-din Farooqui, Marium Altaf

··

Methods of Predicting the Liquid Loading – Comparison Hafiz Muhammad Haleem-ud-din Farooqui, Marium Altaf

Abstract

**NED Univ. of Engineering & Technology

Liquid loading is a common issue in gas well.

Better predictions of liquid loading will help operators in terms of economics and revenue.

ÞÞPakistan

The Turner et al. (1969) entrained-droplet model (or Turner’s model) is the most common method used to predict liquid loading in gas wells.

However, there were still quite a few wells that could not be covered even after 20% upward adjustment (Turner et al. 1969). Field practice also proves that sometimes the adjusted model still underestimates liquid loading.

with the liquid holdup in the gas well once the holdup exceeds the threshold value.

Gas Rate

D S Zhou presents a new empirical model to overcome issue. According to the new model, critNaturalthis Decline ical gas velocity is not of a single value; it varries

Liquid Loading

mhfarooqi89@gmail.com  University  Country  E-mail

Previous models for liquid loading are not dependent on the amount of liquid in a gas stream.

When gas velocity is higher than calculated critical velocity, no liquid loading exists. Zhou points out that, in addition to gas velocity, liquid amount (liquid holdup) in a gas stream is also a major factor for liquid loading. There is a threshold value for liquid amount in a gas/liquid mixture. Above this value, liquid loading may appear even when the

Production impairment

Well intervention Restoring Production Production Time Fig. 1 – Decrease in Production rate due to loading

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24

Methods of Predicting the Liquid Loading – Comparison

gas velocity of a well is higher than the critical velocity from Turner’s droplet model. The presented model is the first model to include the amount of liquids in the calculation of gas critical velocity.

A comparison of Turner’s model and Zhou’s model is presented in this paper. The prediction results from the new model are better than those from Turner’s model. The new model is simple and can be used easily to predict liquid loading in gas wells.

Introduction One of the most serious problems that a gas well can face during its life cycle is Liquid loading. The gas stream, sometimes, may not carry the liquids to the surface and it will accumulate at the well bottom during production. This process of liquid accumulation in a gas well is called liquid loading. As a result of liquids accumulation, the flowing bottom-hole pressure will increase, and the gas-production rate reduces because water saturation around a wellbore increased which reduces the effective gas permeability near the wellbore.

Decrease in production rate makes the loading problem worse, and eventually the loaded liquids will kill the gas well. Fig. 1 illustrates how the liquid

loading can drastically decrease the well rate until a proper well intervention is implemented.

This phenomenon of liquid loading is usually associated with the late life of a gas well as reservoir pressure depletes and controls the well abandonment. For high-liquid/gas-ratio wells, such as in tight gas formations, liquid loading may occur in early production life from poor well planning and completion. These liquids may be free water, condense water and/or condensate. Liquid loading mainly occurs in low energy formations (with low reservoir pressure) and in tight gas regions. This problem can also occur in moderate to high permeability reservoirs with a high condensate to gas ratio (CGR). For high-liquid/gas-ratio wells, such as in tight gas formations, liquid loading may occur in early production life from poor well planning and completion. These liquids may be free water, condense water and/or condensate.

Signs of Liquid Loading Liquid loading is not easily identified. Even when a well is liquid loaded, it may continue to produce for a long time. It follows that if liquid loading is recognized and reduced at an early stage, higher producing rates can be achieved and maintained.

Mist

Annular

Slug

Bubble

Gas Flow

Mist Flow

Slug Flow

Decreasing Gas Velocity Fig. 2 – Flow Regime at different condition in a gas well

25

Hafiz Muhammad Haleem-ud-din Farooqui, Marium Altaf

Fig. 3 – Encountering two liquid droplets in turbulent gas stream

Symptoms indicating liquid loading include the following: ÈÈ

ÈÈ

ÈÈ

Pressure Gradient: Pressure surveys reveal a heavier gradient.

Variance from the Decline Curve: Typically gas wells will follow an exponential-type curve decline; however, liquid loading generally leads to a deviation from the curve with a lower than predicted production rate.

Liquid Slugging: Liquid production does not arrive to the surface in a steady continuous flow, but instead in slugs of fluid. This is readily observed through production monitoring.

Two-phase-flow pattern can also be used to describe the liquid loading phenomenon. The transition from a gas producing well to a liquid-loaded well is accompanied by the transition from an annular-flow regime to the regime of slug or churn flow. Flow regime refers to the geometrical configuration of gas and liquid phases. As described

by Lea et al. (2003), several flow regimes – annular-mist flow, slug/annular-transition flow, slug flow, and bubble flow – may appear in a gas well through its life cycle.

As shown in Fig. 2, the flow regime that is desirable in gas wells is the “mist flow,” where there is a continuous gas phase with evenly dispersed liquid droplets. When a gas well flows below the critical gas flow rate, the flow regime changes to “slug flow,” where the liquid starts accumulating in the wellbore.

Fig. 4 – Liquid loading when threshold value exceeds

Turner's Method Turner et al. (1969) was the first to analyze and predict the minimum gas flow rate to prevent the liquid loading .The Turner et al. entrained drop movement model was derived on the basis of the terminal-free settling velocity of liquid drops and the maximum drop diameter corresponding to the critical Weber number of 30. According to Turner et al. (1969), gas will continuously remove liquids from the well until its velocity drops to below the terminal velocity. The minimum gas flow rate for a particular set of conditions (pressure and conduit geometry) can be calculated using a mathematical model.

Turner et al. (1969) concluded that wellhead conditions were the controlling factors for liquid loading and suggested evaluating the critical velocity at the wellhead. The major advantage of using wellhead conditions is to simplify calculations to obtain the pressures and temperatures along tubings.

However, it was pointed out that the controlling condition for Turner’s model is at bottom-hole, and the evaluation of critical velocity should be made at bottom conditions, especially when there is a larger-diameter segment above well’s perforation (Coleman et al. 1991; Lea et al. 2003).

Guo's Method Guo's method refers to the method presented by Guo, Ghalambor, and Xu (2006) Starting

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Methods of Predicting the Liquid Loading – Comparison

from Turner et al.'s entrained drop model, Guo et al. (2006) determined the minimum kinetic energy of gas that is required to lift liquids.

A four-phase (gas, oil, water, and solid particles) mist-flow model was developed. Applying the minimum kinetic energy criteria to the fourphase flow model resulted in a closed form analytical equation for predicting the minimum gas flow rate. Through case studies Guo et al. (2006) demonstrated that Guo's method is more conservative and accurate.

Zhou Model Two mechanisms have been proposed for predicting liquid loading in gas wells: entrained-liquid-droplet model and liquid-film model. As concluded by Turner et al. (1969), the liquid-droplet model represents the liquid-loading problem, but the liquid-film model does not.

Turner’s entrained-liquid-droplet model is based on the force balance on a single droplet (as shown in Fig. 2) and does not include the encounter effect. For low liquid-droplet concentration, the chance of encounters is low and Turner’s model works well. However, when the liquid concentration reaches a certain value, the encounter coalescing falling process of liquid droplets in a gas stream will dominate the entrained-liquid-droplet movement, and hence Turner’s single liquid-droplet model losses its function, even with gas-stream flows faster than critical velocity.

If there are more liquid droplets in the gas stream, the chance of the process of liquid-droplet encountering, coalescing, falling, and shattering increases.

As the number of liquid droplets in a gas stream, called liquid-droplet concentration here, increases to a threshold value β, the process of droplets encountering, coalescing, falling, and shattering will continue and bring those liquid droplets down to the well bottom. (as shown in Fig. 4) Liquid holdup can be used to represent the liquid droplet concentration in a gas well. Liquid holdup is defined as

Hl =

vsl [1] vsg + vsl

Liquid-droplet concentration is the control factor in droplet encounters. The higher the concentration of liquid droplets in a turbulent gas stream, the greater the chance that the droplets will combine and fall. The concentration of liquid droplets in a gas stream may be the third mechanism contributing to liquid loading, in addition to the liquid-film mechanism and Turner’s liquid-droplet mechanism.

Critical Velocities for a Gas Well There is a threshold value of liquid-droplet concentration, β, below it, the entrained-liquid droplets do not encounter, or they do encounter coalesce fall shatter, but still are brought out of the well by the gas stream before they accumulate at bottom-hole. Turner’s model can be used in this situation. But above the threshold concentration value, the gas velocity should be higher to provide higher drag force and to bring bigger droplets at surface. Higher gas velocity has also prevents bigger-liquid-droplet formation and shatters bigger droplets faster. Therefore, the critical velocity for liquid loading is not a single value. It varies with the liquid-droplet concentration (amount of liquid) in a gas stream once the concentration exceeds the threshold value, According to the liquid-droplet-concentration mechanism; Zhou et al. (2010) propose an empirical correlation to estimate the critical velocities for gas-well liquid loading as For Hl ≤ β 1

vcrit−N = vcrit−T = 1.593

[σ(ρl − ρ g )] ρg

1

2

4

[2]

For Hl >β vcrit−N = vcrit−T + ln

Hl + α [3] β

The new model is composed of two parts. When liquid holdup is lower than or equal to the thresh-

859

1148

775

417

712

1525

2611

1814

1797

2502

1247

1356

800

725

400

540

3607

3340

3540

1895

1861

760

1102

500

1.955

1000

Table 2 – Application of Zhou model to synthetic data

3.958

2.441

1000

700

2.441

2000

1.755

(inches)

(psi)

700

Tubing ID

Well Head Pressure

Table 1 – Comparison of Turner’s model and Zhou’model

1726

1419

875

1635

2412

1156

661

583

779

(Mscf/D)

(Mscf/D)

(psi)

QCRIT-T

QTEST

Well Head Pressure

QTEST

16023

8985

11502

19375

9880

(Mscf/D)

4.65

6.47

8.63

10.59

7.47

2.7

2.74

3.33

10.39

8.21

5.62

(ft/sec)

vsgwh

9050.06

1123.23

1123.3

11230

8910

(Mscf/D)

QCRIT-T

10.04

6.77

7.95

3.64

3.64

2.43

2.53

2.52

9.64

11.48

5.65

(ft/sec)

vCRIT-T

vCRIT-T (ft/sec)

25.87203

16.33221

9.213632

59.0844

23.43909

0.004

0.135

0.227

0.405

0.291

0.412

0.455

0.171

0.045

0.022

0.009

(ft/sec)

vslwh

0.001

0.02

0.026

0.037

0.038

0.132

0.142

0.049

0.004

0.003

0.002

Hl

27.29909

17.49277

9.213632

59.0844

26.06357

(ft/sec)

vCRIT-N

10.04

7.75

9.1

5.09

5.11

5.06

5.23

4.23

9.64

11.48

5.65

(ft/sec)

vCRIT-N

9549.247

1203.046

1123.3

11230

9907.653

(Mscf/D)

QCRIT-N

1726

1623

1315

1203

1229

3403

4985

1935

661

583

779

(Mscf/D)

QCRIT-N

Loaded UP

Loaded UP

Loaded UP

Unloaded

Unloaded

Loaded UP

Loaded UP

Loaded UP

Unloaded

Loaded UP

Loaded UP

Unloaded

Unloaded

Unloaded

Unloaded

Loaded

Loaded Up

Loaded Up

Loaded Up

Unloaded

Unloaded

Loaded Up

Loaded Up

Loade d Up

Loaded Up

Loaded Up

Loaded Up

Test Status

Unloaded

Loaded

Loaded

Unloaded

Loaded

Status (Based on Software calculation)

Prediction by new model

Prediction by new model

Loaded UP

Loaded UP

Unloaded

Unloaded

Unloaded

Unloaded

Unloaded

Unloaded

Unloaded

Loaded UP

Loaded UP

Prediction By Turners

Hafiz Muhammad Haleem-ud-din Farooqui, Marium Altaf 27

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Methods of Predicting the Liquid Loading – Comparison

old value, the critical-velocity model is the same as Turner’s model. When liquid holdup is greater than the threshold value, the critical velocity varies with the liquid holdup and can be calculated from the new model. The critical-rate correlation for the new model is the same as that by Turner et al. (1969), which is given by qcrit−N =

3060 pvcrit−N A [4] Tz

Application of Zhou Model (new Model) The data from Turner et al. (1969) were used to evaluate the Zhou model parameters. Table 1 shows some of the calculation and comparison between results of the two models. The calculated results are the same for both Turner’s and Zhou model when the liquid droplet concentration is below the threshold value. But when this liquid droplet concentration value exceeds the threshold value, the results from Turner’s model are not reliable and the Zhou’s liquid droplet concentration model found its application. The parameters α =0.6 and β=0.01 in the concentration model give an adequate estimation to Turner et al data.

The data from a commercial software package is also used to compare the results of the two models.

The results are shown in Table 2.

Conclusion The model proposed by Zhou et al (2010) can be divided into two parts on the basis of a threshold value of liquid holdup. When the liquid droplet concentration is below the threshold value, the model is same as the Turner’s model. Above the threshold value, critical velocity increases with the increase of liquid hold up and which can be predicted by the new model. The model is simple and easy to use and covers more number of wells than Turner’s model.

Nomenclature A – Bg – Bgwh – Bw – dcsgID – dtbgID – dtbgOD – T – Hl – p – Qc – Qcrit-N – Qcrit-T – Qg – Ql – Q-test – T – vcrit – vcrit-N – vcrit-T – vg – vsg – vsl – vsgwh – vslwh – yc – yw – z – α – β – ρg – ρl – σ –

flow cross-sectional area of a conduit, ft2 gas formation volume factor gas formation volume factor at wellhead water formation volume factor casing inside diameter, in2 tubing inside diameter, in2 tubing outside diameter, in2 temperature, ˚F liquid holdup at wellhead wellhead pressure, psi condensate rate, B/D gas critical rate from the new ( Zhou) model in this paper, Mscf/D gas critical rate from Turner’s model, Mscf/D producing gas rate, Mscf/D liquid rate, B/D gas-test rate, Mscf/D temperature, °R critical speed, ft/sec critical speed from the new model in this paper, ft/s critical speed from Turner’s model, ft/sec producing-gas velocity, ft/s gas superfcial velocity, ft/s liquid superficial velocity, ft/s gas superficial velocity at wellhead, ft/s liquid superficial velocity at wellhead, ft/s condensate yield, bbl/MMscf water yield, bbl/MMscf gas z factor parameter in new model, 0.6 or 0 the threshold value of liquid droplet concentration, 0.01 for petroleum gas wells gas density, lbm/ft3 liquid density, lbm/ft3 interfacial tension, dynes/cm

Acknowledgments Authors would like to thank their colleagues and friends for their support and help during preparation of this paper. 

Hernando Buendía Lombana, Juan Carlos Lizcano Niño, Robert Eduardo Padrón García

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29

A Novel Methodology for the Construction of Homogeneous Synthetic Sandstone Cores Hernando Buendía Lombana, Juan Carlos Lizcano Niño, Robert Eduardo Padrón García

In order to develop laboratory tests related to special petrophysics, formation damage or EOR processes, the construction of homogeneous synthetic cores with specific petrophysical properties is very important. Samples from native cores or famous homogeneous outcrops (i.e. Berea Sandstones or Baker Dolomites) are sometimes very expensive or just unavailable.

Therefore, synthetic cores have become indispensable for investigation purposes. The construction of sandstone synthetic cores generally consists of a mixture made from fine sand (80–100 mesh), white kaolinite and an epoxy solution for cementing the sample. The ideal proportion of these materials forms the “formulation”, which, combined with certain amount of compression, makes it possible to obtain the petrophysical properties desired. Several attempts to find the ideal formulation in function of the petrophysical properties were made, but previous methodologies were not standardized, as the compression effect was neither accounted, nor quantified.

In the following study a satisfactory measurement of the compression related to the construction process was performed by means of a torque wrench. By controlling this variable, a correlation between the compression applied and the absolute permeability of the core was obtained showing a direct relationship.

All the samples made in this work show the same density, proving somehow the similarity between the samples. Further works are required to develop a standardized procedure of construction of homogeneous sandstone samples.

**Universidad Industrial de Santander ÞÞColombia herbuen@uis.edu.co juan.lizcano@correo.uis.edu.co robert.padron@correo.uis.edu.co  University  Country  E-mail

Introduction The construction of synthetic cores has always been very important for running laboratory tests related to diverse processes in petroleum industry. Despite that, studies regarding this matter are rather limited. Stegemeier and Jessen work [13] related to wettability is the first study concerning artificial coring. The cores were made from Teflon marbles and then consolidated by heating in a procedure explained in Mungan wettability work [6].

Teflon was the material in these cases, because it leads to less chemical interactions with oil, which is a desirable property in terms of wettability studies. Alumina and stainless steel marbles were also used as materials for synthetic cores [3]. More studies regarding wettability of artificial rock samples were compiled by Anderson [1].

More recent studies can be found in a different field: rock mechanics. There are plenty of studies related to tensile efforts and fractures carried in synthetic rocks with epoxic material as a fracture bounder [2, 10, 12].

Much research has been made in Colombia in attempt to develop a standardized methodology

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30

A Novel Methodology for the Construction of Homogeneous Synthetic Sandstone Cores

Fig. 1 – Adapted assembly for core synthetic construction for the construction of synthetic core samples.

Muñoz et al. (at UIS) have put many efforts into this subject. Their studies are related to the experimental representation of EOR processes such as waterflooding and steamflooding. In their first study [7], a methodology for the construction of homogenous sandstone samples was outlined using kaolinite as a permeability reducing agent, epoxic material as a cementing agent, and suited in a Radial Displacement Equipment (EDR), detailed in other study by Londoño et al. [4].

They attempted later to construct stratified porous media for displacement proposes [8]. They described all the variables involved in the con-

struction process, being all controllable, except for compression. Compression was made manually by means of a piston – a PVC sleeve and a common hammer. Moreover, the effectiveness of permeability reducing agents was evaluated by using different materials (i.e., bentonite, white cement, and two varieties of kaolinite). White kaolinite was reaffirmed as the most effective reducing agent, and a correlation between percentage of kaolinite and petrophysical properties was constructed. However, since the compression was not controlled, there is no control on the reproducibility of the process. Muñoz et al. [9] corroborate this fact by reproducing samples made with the same composition but compressed for two different operators,

Hernando Buendía Lombana, Juan Carlos Lizcano Niño, Robert Eduardo Padrón García

31

Fig. 2 – Mixture of fine sand and white kaolin

Fig. 3 – Mixture of resin and hardener, the epoxy solution

and concluding that compression is a fundamental variable. In conclusion, these methodologies were not standardized yet, because not all the variables involved were controlled.

mold for the final mixture. This PVC tube should have an internal diameter of 1 ½ inches (API RP40 Standard Recommended Practices). To compact the final mixture and to assure the repetitiveness and reproducibility of the absolute permeability of the core, an assembly was adapted with a stem and a torque wrench (Fig. 1). The torque wrench provides a specific torque toward the stem, it transforms the torque to pressure into the mixture in the PVC sleeve.

In UNAL, Medellín, Lopera et al. [5] developed a different methodology; using Ottawa sand with different grain size and concluding that the size of grains is proportional to the petrophysical properties obtained. Epoxic material is not mentioned as a cementing material, and the compression is made by means of a rubber sleeve and brine displacement.

Taking into account all of these studies, it is clear that in order to develop a standardized methodology, the quantification of compression is absolutely necessary. There is a need to develop newer and more efficient methods for the construction of homogeneous porous media, which are our primary material for the characterization of many reservoir processes, from scale deposition to steamflooding.

Experimental Procedure In the process of construction of synthetic cores needed are: fine sand (80–100 mesh), white kaolin, epoxy solution (mixture of resin and hardener), which acts as a cementing material between the fine sand and white kaolin, PVC sleeve as a

The first step is to select desired permeability or porosity in synthetic cores. The quantities of fine sand, white kaolin, resin and hardener are defined by correlations established in Muñoz et al. work [8] to make the mixture for the construction of the cores.

The second step is to measure the quantities defined in the previous step and mixing. The mixture of fine sand and white kaolin should be in a vessel (Fig. 2) and the mixture of resin and hardener in another vessel, conforming the epoxy solution (Fig. 3). Each preparation should be mixed until it becomes uniform and homogeneous.

The third step is to put the mixture into the PVC sleeve; the mixture is compressed to a specific value of torque (and consequently pressure) by the adapted assembly. The transition from step two to step three should be fast, because the epoxy solution could dry.

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32

A Novel Methodology for the Construction of Homogeneous Synthetic Sandstone Cores

250 200 150 100 50 0

0

5

10

15

20

25

30

35

40

Fig. 4 – Correlation between absolute permeability vs. applied torque

The fourth and final step is to dry the mixture in a PVC sleeve for about 3 to 4 days at environmental temperature. After this period PVC sleeve is removed.

Results and Discussion By using this procedure, 13 synthetic cores were constructed. The formulation which was designed for permeability of 50 mD was constant (Table 1), whereas the compression applied to each core varied. The results are presented in Table 2. In the construction of sample 1, some drawbacks were present in the application of the desired torque, therefore, sample 2 was made with the same torque as applied in sample 1. It did not present any problem in its construction. Hence, they differ in the absolute permeability value.

The construction of samples 4 and 5 was different.

In sample 4, the pressure was applied only once and then the core was dried at environmental conditions, while in sample 5, the pressure was applied for 5 days with the PVC sleeve being subsequently removed. However, the results were not as expected – sample 5 was more permeable than sample 4.

The phenomenon expected was that the sample

which was compressed for 5 days would be less permeable. Basing on this, we cannot draw any conclusions yet. These differences are attributable to the mixing process since the mixture was not completely homogeneous due to the presence of lumps of cementing material. In the construction of sample 10, drawbacks were also present. As in sample 1, it was not possible to apply the desired compression.

However, in general terms, the methodology turned out to be effective, repeatable, and demonstrated the existence of a direct correlation between the applied compression and absolute permeability in each sample. The density of the grain material was practically the same in all samples (2.35 g/cm3). Fig. 4 shows the linear dependence between these two variables, samples 1 and 10 did not count in this figure, due to the problems in their construction process. We can conclude that the desired permeability is reached at a torque value of 35 lb-ft.

Conclusions The standardization of a new methodology for the construction of homogeneous synthetic rock

Hernando Buendía Lombana, Juan Carlos Lizcano Niño, Robert Eduardo Padrón García

Desired Permeability (mD)

50

White Kaolin Mass (g)

62

Fine Sand Mass (g)

151

Resin volume (ml)

6

Hardener volume (ml)

15

33

on the Permeability measurements. Basing on a previous conclusion, we can assume that the theoretical permeability is reached in a 35 lb-ft torque value.

Table 1 – Formulation synthetic cores to 50 mD

samples is a vital need for the petroleum industry, because it provides trustful materials for developing innovation in laboratories A novel methodology of compression was established. It measures the amount of compression applied to samples (understanding that the compression applied to the cores is a significant variable in the posterior petrophysical properties calculation) A correlation between Compressibility and Absolute Permeability was observed, providing the evidence for the significant effect of this variable

Further studies are required in order to develop a more effective and standardized methodology.

The challenges in this area include forming of the lumps in preparation of samples, and validation of the previous concepts. The correlations between formulation and petrophysical properties (i.e. porosity and permeability) obtained in previous works should be revised in the near future.

Acknowledgments The authors of this article want to express their gratitude for the Petroleum Engineering department of the Universidad Industrial de Santander, to all the professionals of Parque Tecnológico Guatiguará, to Luis Felipe Carrillo, M.Sc. for his guidance, and to Camilo Guerrero, Ambassador for YoungPetro Latin America. 

SI Unit Conversion Factors ft2 x 9.290304* E-02 = m2 • in x 2.54* E+00 = cm •mD x 9.869233* E-04 = μm2 • *Conversion factor is exact Synthetic Core

Torque (lb-ft)

Name

Average Diameter (cm) Average Length (cm)

Average Permeability (mD)

1

10

10 lb-ft

3.787

7.580

66.20

2

10

10 lb-ft

3.808

7.410

217.76

3

15

15 lb-ft

3.805

7.430

209.55

4

20

20 lb-ft

3.800

6.920

136.00

5

20

20 lb-ft SOST

3.805

6.615

185.73

6

25

25 lb-ft

3.795

7.581

86.24

7

30

30 lb-ft

3.799

7.509

115.16

8

30

30 lb-ft

3.799

7.207

135.57

9

35

35 lb-ft

3.803

6.860

70.71

10

25

25 lb-ft

3.710

7.280

21.72

11

30

30 lb-ft

3.790

7.640

45.53

12

35

35 lb-ft

3.780

8.170

45.15

13

35

35 lb-ft

3.700

4.310

48.31

Table 2 – Synthetic cores results

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A Novel Methodology for the Construction of Homogeneous Synthetic Sandstone Cores

References 1. Anderson, W.G. (1986, October). Wettability literature Survey – Part 1: Rock/Oil/Brine Interactions and the Effects of Core Handling on Wettability. Journal of Petroleum Technology, 38(10), 1125–1144.

SPE paper No. 13932.

2. Ding, P., Di, B., Wei, J., Li, X., & Deng, Y. (2014). Fluid-dependent Anisotropy and Experimental Measurements in Synthetic Porous Rocks with Controlled Fracture Parameters. Journal of Geophysics and Engineering, 11, 9.

3. Lefebvre du Frey, E.J. (1973, February). Factors Affecting Liquid-Liquid Relative Permeabilities of a Consilidated Porus Medium. Society of Petroleum Engineering Journal, 13(01), 39–47. SPE paper No. 3039.

4. Londoño, F.W., Muñoz, S., & Naranjo, C.E. (2013). El Resurgimiento de la Técnica de Escalamiento de Procesos de Recobro de Hidrocarburos – de laboratorio-campo o campo-laboratorio. Proc. XV Expo Oil and Gas ACIPET, Bogotá, Colombia. 2013.

5. Lopera, S., Zapata, F., & Mejía V. (2013). Construcción de Medios Porosos Artificiales para Desplazamientos en Medios Porosos. Proc. XV Expo Oil and Gas ACIPET, Bogotá, Colombia. 2013.

6. Mungan, N. (1966, September). Interfacial Effects in Inmmiscible Liquid-Liquid Displacement in Porous Media. Society of Petroleum Engineering Journal, 6(03), 247–253. SPE paper No. 1442.

7. Muñoz, S., Ibarra, Y.A., & Celis, J.O. (2011). Estudio Experimental y Numérico del proceso de Inyección de Agua en el Modelo de Desplazamiento Radial. Undergraduate Thesis of Petroleum Engineering, Universidad Industrial de Santander. Bucaramanga, Colombia 2011. Available at Repositorio UIS. 8. Muñoz, S., Celis, L.A., & Fernandez de Castro, O.D. (2012). Estudio Experimental de Procesos de Inyección de Agua en el Equipo de Desplazamiento Radial con Medios Porosos Estratificados. Undergraduate Thesis of Petroleum Engineering, Universidad Industrial de Santander. Bucaramanga, Colombia 2012. Available at Repositorio UIS. 9. Muñoz, S., Alarcón, L.A., & Cavanzo, E.A. (2013). Estudio Experimental de un Proceso de Inyección Continua de Vapor en el Equipo de Desplazamiento Radial con Medios Porosos Homogéneos. Undergraduate Thesis of Petroleum Engineering, Universidad Industrial de Santander. Bucaramanga, Colombia 2013. Available at Repositorio UIS. 10. Nguyen, S.H., Chemenda, A.I, & Ambre, J. (2011). Influence of the loading conditions on the Mechanical response of granular materials as constrained from experimental tests on Synthetic Rock analogue material. International Journal of Rock Mechanics and Mining Sciences, 48, 103–105.

11. Recommended Practices for Core Analysis. (1998, February). API RP40. Second Edition.

12. Singh, M., Lakshmi, V., & Srivastava, L.P. (2014, January). Effect of Pre-loading with Tensile Stress on Laboratory UCS of a Synthetic Rock. Rock Mechanics Engineering Society Journal.

13. Stegemeier, G., & Jessen, F.W. (1959, March). The Relationship of Relative Permeability to Contact Angles. Conference on the Theory of Fluid Flow in Porous Media. Oklahoma, OK. March 23–24, 1959.

Cited in Anderson (1986).

35

Steffones K, Abhishek Tyagi, Akul Narang

··

EOR Evaluation Using Artificial Neural Network Steffones K, Abhishek Tyagi, Akul Narang

Enhanced Oil Recovery (EOR) has gained great attention as a result of higher oil prices and increasing oil demands. Extensive research have been conducted to develop various EOR methods, evaluate their applicability and optimize operation conditions. One of the principal areas is to develop an effective tool for selection of a suitable EOR method according to oil field characteristics. The main objective of the studies is to screen various EOR methods based on field characteristics and evaluate their technical/economic applicability in an efficient way instead of predicting the field performances of all possible competing strategies and comparing their economics.

In this paper, we present an Artificial Neural Network (ANN) approach to enable the petroleum engineer to select an appropriate EOR method with the given reservoir properties. The ANN developed in this study is a four-layered feed-forward Back Propagation (BP) network consisting of one input and output layer with two hidden layers. The input layer is composed of the key reservoir parameters (reservoir depth, temperature, porosity, permeability, initial oil saturation, oil gravity, and in-situ oil viscosity), while the output layer is composed of the five EOR methods to be evaluated (steam, CO 2 miscible, hydrocarbon miscible, in-situ combustion, polymer flooding).

The number of hidden layers and neurons are optimized during the training by repeated trial and error. After trained successfully, the ANN is tested and applied to other fields which are not used for the training.

A series of the test results shows that the ANN developed in this study can be used to select the most appropriate EOR process according to reservoir rock and fluid characteristics in a time and cost effective way.

**University of Petroleum & Energy Studies ÞÞIndia cephanos26@gmail.com  University  Country  E-mail

Introduction Higher oil prices and concerns about future oil supply lead to increased interest in Enhanced Oil Recovery (EOR) around the world. Because EOR projects are generally more expensive and involve higher front-end costs than conventional secondary projects, effective planning takes on added importance [9]. A large number of studies have been conducted to help the petroleum engineer select efficient EOR methods with limited field information. The main objective of the studies is to select the suitable EOR method in an effective way without predicting the reservoir performance of all possible competing strategies and comparing their economics.

Most of early studies in the EOR selection were to establish the technical screening criteria of each EOR method [7, 14, 15]. Based on laboratory experiments and field experiences, the applicable ranges of the reservoir rock and fluid properties were presented in these studies. The effort has been added in several studies to update the applicable ranges with the current technical and economic conditions [1, 4]. The problem of selection and implementation of proper EOR techniques was also addressed in some papers as a guide for petroleum engineers [16].

The improvement of computer technology introduced the artificial intelligence technique into

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EOR Evaluation Using Artificial Neural Network

EOR selection [5, 8, 10, 12, 13]. Because the values of these models strongly depend on the accuracy of the input data, it should be continuously updated with up-to-date operation data. In this paper, we developed the Artificial Neural Network (ANN) incorporating the recent database published in the industry. The main goal of the study is to develop the ANN model that can estimate the best EOR method according to the given reservoir rock and fluid properties in a time and cost effective way and evaluate applicability of the model.

vised training. One of the widely used supervised networks is the feed-forward Back Propagation (BP) network which adjusts the connection weights during the back propagation process.

Artificial Neural Network ANN is an information-processing system that has certain performance characteristics in common with biological neural networks. A typical neural network is a multilayered system consisting of single input layer, single or double hidden layer, and single output layer. Each layer is composed of basic processing elements called neurons. Each neuron is connected to the neurons of the adjacent layer with the connection eights between 0 and 1.

The signals between the neurons are multiplied by the associated connection weights and added up together as Eq. 1, and then used as the net input of the neuron. n

NET = ∑I k W k [1] k=1

Where NET is the net input of the neuron, I is the input variable, W is the connection weight, k is the index, and n is the number of input variables. Each neuron applies an activation function to its net input to determine its output signal and the signal is transmitted to the next neuron. The sigmoid function in Eq. 2 is an activation function commonly used. f ( NET ) =

1 [2] 1 + e NET

The connection weights between the neurons are adjusted during the training. There are two ways of the training; supervised and unsupervised.

For most typical neural network, the connection weights are adjusted by the given input and corresponding output. This process is called as super-

In this study, the BP network with the training algorithm of Scaled Conjugate Gradient (SCG) which is a new variation of the conjugate gradient method is used. SCG allows the avoidance of the line search per training iteration of Levenberg-Marquardt approach in order to scale the step size.

Data Source and Preparation The data used for training and testing the networks are extracted from the special reports, Worldwide EOR Survey published by Oil and Gas Journal [11].

The reports include the field name, reservoir rock and fluid properties, project maturity and project evaluation of the field where the EOR was being applied. In this study, the data of those fields were evaluated where application of EOR was successful. Neurons of the input layer are designed to be the main reservoir properties.

The seven reservoir properties which are reservoir depth, temperature, porosity, log permeability, initial oil saturation, oil gravity, log oil viscosity are selected as the input variables of the ANN model.

Step 1

Divide the input variables into two groups by their effects on the selection ∙ Group 1: porosity, log permeability, oil saturation, log oil viscosity Group 2: depth, temperature, oil gravity

Step 2

Multiply the variables for each group V1 = porosity × log permeability × oil saturation × log oil viscosity V2 = depth × temperature × oil gravity

Step 3

Generate the group variable by dividing V1 by V2

Step 4

Rank each data by group variable and group each three data

Step 5

Sample two data for each group

Table 1 – Data sampling method by group variable

37

Steffones K, Abhishek Tyagi, Akul Narang

EOR type

Total

Training

Testing

Reservoir parameters

Min

Avg

Max

Steam

103

70

33

Reservoir depth (ft)

200.0

4,079.0

13,750.0

Carbon dioxide miscible

65

45

20

Reservoir temperature (℉)

45.0

126.9

290.0

Hydrocarbon miscible

32

22

10

Porosity (%)

3.0

23.3

65.0

In-situ combustion

15

11

4

Permeability (mD)

0.1

1,283.6

11,500.0

Polymer flooding

15

11

4

26.5

62.8

98.0

Total

230

159

71

Initial oil saturation (% of OOIP) Oil gravity (°API)

8.0

24.9

57.0

In-situ oil viscosity (cP)

0.1

26,594.4

200,000.0

Table 2 – The number of data used for the training and the applicability test

Table 3 – Ranges of the input reservoir parameters

A new variable is generated by grouping the input reservoir parameters to sample the data to be used for the training and two-thirds of the total data are selected based on this group variable as summarized in Table 1. For training efficiency, the sampling ratio increases to three-fourths if the number of sampling data is less than ten. The remaining data which are not included in the training are used for testing the developed ANN model.

Table 2 shows the number of data for the training and the applicability test.

The ranges of the input reservoir parameters are summarized in Table 3. Each input variable is normalized between 0 and 1 before the training for numerical stability as defined in Eq. 3.

The normalized input variables are then entered into the input neurons to train the network.

X norm =

X actual − X min [3] X max − X min

Where Xnorm is the normalized input variable, Xactual is the original value of the variable, Xmin is the minimum value of the variable and Xmax is the maximum value of the variable. The ranges of the input reservoir parameters are summarized in Table 3.

The neurons of the output layer are composed of the EOR methods to be selected. The five EOR methods (steam, carbon dioxide miscible, hydrocarbon miscible, in-situ combustion, polymer

flooding) which are being applied in more than ten fields consists in the output layer. The target value of the output neurons are designed to be +1 in the neurons indicating the successfully applied EOR methods and -1 in other neurons indicating other EOR methods.

Development of ANN Model Design and training of the ANN is done in the software developed by our team in Visual Studio (NET IDE ) The object function in the training is the mean square error as defined in Eq. 4 and the convergence tolerance is initially designed to be 0.001.

N

Error =

1 p ∑( yi − f (xi ))2 [4] N i=1

Where Np , yi, and f(xi) indicate the number of data, the measured output and estimated output by the model respectively.

As an activation function, the tangent sigmoid function is used for the first hidden layer and the logistic sigmoid function is used for the second hidden layer. For the output layer, the linear function is used [10]. The structure of the ANN model, that is the number of neurons of the hidden layers, is optimized during the training by repeated trial and error. Maximum number of iteration is set to 10,000.

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EOR Evaluation Using Artificial Neural Network

Reservoir Properties

x1

w1 u1 EOR Methods +1 or -1

w2 u2

x2

w3 u3

y1 y2 y3

x3 x4

w4 w5 w6

u4

y4

u5

y5

u6

Fig. 1 – Structure of the ANN model developed in this study

Conclusion A four-layered ANN model is developed to select the most suitable EOR method based on the field characteristics. The input layer consists of the seven reservoir parameters and the output layer consists of the five EOR methods to be selected.

The number of neurons in the hidden layers is

optimized during the training; ten for the first hidden layer and eight for the second hidden layer.

After trained successfully with the successful EOR field data, the ANN model is tested against the data excluded in the training. The model correctly selected the best EOR method with the accuracy greater than 95%. 

Steffones K, Abhishek Tyagi, Akul Narang

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References 1. Aladasani, A., & Bai, B. (2010). Recent Developments and Updated Screening Criteria of Enhanced Oil Recovery Techniques. SPE paper No. 130726. CPS/SPE International Oil & Gas Conference and Exhibition, Beijing, China. June 8–10, 2010.

2. Beale, M.H., Hagan, M.T., & Demuth, H.B. (2010). Neural Network ToolboxTM 7, Massachusetts, MA. MathWorks.

3. Chung, T.-H., & Carroll H.B. (1995). Application of Fuzzy Expert Systems for EOR Project Risk Analysis. SPE paper No. 30741. SPE Annual Technical Conference and Exhibition, Dallas, TX. October 22–25, 1995.

4. Dickson, J.L., & Wylie, P.L. (2010). Development of Improved Hydrocarbon Recovery Screening Methodologies. SPE paper 129768. SPE Improved Oil Recovery Symposium, Tulsa, OK. April 24–28, 2010.

5. Elemo, R.O., & Elmtalab, J. (1993). A Practical Artificial Intelligence Applicationin EOR Projects. SPE Computer Applications, 4(2), 17–21.

6. Flanders, W.A., & DePauw, R.M. (1993). Update Case History: Performance of the Twofreds Tertiary CO2 Project. SPE paper No. 26614. SPE Annual Technical Conference and Exhibition, Houston, TX. October 3–6, 1993.

7. Goodlett, G.O., Honarpour, F.T., Chung, F.T., & Sarathi, P.S. (1986). The Role of Screening and Laboratory Flow Studies in EOR Process Evaluation. SPE paper No. 15172. Rocky Mountain Regional Meeting, Billings, MT. May 19–21, 1986.

8. Guerillot, D.R. (1988). EOR Screening With an Expert System. SPE paper No. 17791. Symposium on Petroleum Industry Applications of Microcomputers, San Jose, CA. June 27–29, 1988.

9. Hite, J.R., Avasthi, S.M., & Bondor, P.L. (2004). Planning EOR Projects. SPE paper No. 92006. SPE International Petroleum Conference, Puebla, Mexico. November 8–9, 2004.

10. Lee, J.-Y., & Lim, J.-S. (2008). Artificial Neural Network Approach to Selection of Ehanced Oil Recovery Method. Journal of the Korean Society for Geosystem Engineering, 45(6), 719–726.

11. Moritis, G. (2010). Worldwide EOR Survey. Oil & Gas Journal, 108(14), 41–53.

12. Shokir, E.M. El-M., Goda, H.M., Sayyouh, M.H., & Fattah, Kh.A. (2002). Selection and Evaluation EOR Method Using Artificial Intelligent. SPE paper No. 79163. 26th Annual SPE International Technical Conference and Exhibition, Abuja, Nigeria. August 5–7, 2002.

13. Surguchev, L.M., & Li, L. IOR Evaluation and Applicability Screening Using Artificial Neural Networks. SPE paper No. 59308. SPE/DOE Improved Oil Recovery Symposium, Tulsa, OK. April 3–5, 2000.

14. Taber, J.J., & Martin, F.D. Technical Screening Guides for the Enhanced Recovery of Oil. SPE paper No. 12069. 58th Annual Technical Conference and Exhibition of SPE of AIME, San Francisco, CA. October 5–8, 1983.

15. Taber, J.J., Martin, F.D., & Seright, R.S. EOR Screening Criteria Revisited. SPE paper No. 35385. SPE/ DOE Tenth Symposium on Improved Oil Recovery, Tulsa, OK. April 21–24, 1996.

16. Zerafat, M.M., Ayatollahi, S., Mehranbod, N., & Barzegari, D. (2011). Bayesian Network Analysis as a Tool for Efficient EOR Screening. SPE Enhanced Oil Recovery Conference, Kuala Lumpur, Malaysia.

July 19–21, 2011.

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åå

System which Rules South-Eastern Europe – Russian Gas Pipelines

System which Rules South-Eastern Europe – Russian Gas Pipelines Radosław Budzowski

Russia, Western Siberia. Here is situated the heart and thus the beginning of the Russian pipelines. Rich deposits of natural gas are exactly here. Let's take a closer look at the largest network of gas pipelines. The idea of gas transit from Russia to Western Europe was born in 1992. Since then, the network of pipelines in Europe has evolved considerably. Let’s just mention the Yamal-Europe pipeline, South Stream, Brotherhood or Nord Stream pipeline. Russia is the second-largest producer of dry natural gas and third-largest liquid fuels producer in the world. It is no wonder that the economy of the country (as well as European economy) depends on petroleum industry. In 2012, oil and gas revenues accounted for 52% of the federal budget and more than 70% of total exports.

About 76% of natural gas is sent by Russia to Western Europe (mostly to Germany, Turkey, Italy, UK and France). It can be said that most countries in Europe are dependent on gas supplies from Russia. Due to the political crisis in Ukraine, the topic of Russian gas pipelines has become a burning issue recently.

Gas Infrastructure As stated in “Oil and Gas Journal”, Russia has the largest natural gas deposits, with 1,688 trillion cubic feet. Most of them are located in Western Siberia. The largest fields are in Yamburg, Urengoy and Medvezh’ye. However, Gazprom is investing in oil extraction in other parts of the country. In 2010, estimated gas reserves amounted to 59.650 bcm which represents 31.51% of world reserves. Natural gas is transported through the Unified Gas Supply System (UGSS), a network of

gas pipelines and branches that covers the whole Russian territory and connects with foreign pipelines for export. The UGSS comprises facilities for gas extraction, processing, transmission, storage, and distribution, and is the world’s largest gas transmission system. Unified Gas Supply System (owned by Gazprom) controls about 104,000 miles of pipelines and 268 compressor stations, 6 gas processing plants and 25 underground gas storage facilities with a total capacity of 2.4 Tcf. At the moment, there are 10 large pipelines transporting gas in Russia. 8 of them are export pipelines: Yamal-Europe I, Northern Lights, Soyuz, Brotherhood, Blue Stream, Nord Stream, North Caucasus and Mozdok-Gazi-Magomed. The first four transport natural gas through Belarus and Ukraine to other European countries, whereas the others transport natural gas to Turkey and some former Soviet Union countries. The Yamal-Europe pipeline supplies gas from Russia to Poland and Germany (capacity 1.2 Tcf per year). A real technical achievement during the construction of the Yamal-Europe pipeline was the open excavation through the Vistula to intersection the river by a pipeline with a 1,400 mm diameter.

Another interesting gas pipeline is the Brotherhood which has a carrying capacity of 3.5 Tcf per year, running across Ukraine up to Slovakia where it divides into two branches. The northern line reaches the Czech Republic, Germany, France and Switzerland, and the southern line runs through the Austrian gas hub in Baumgarten and supplies gas to Italy, Hungary and several countries of former Yugoslavia. These gas pipelines are located within the territory of many countries. Therefore it is necessary to pay transit fees to these countries,

Radosław Budzowski

41

Fig. 1 – The most important Russian pipelines

which is one of the major problems of the Russia’s Government with respect to gas export.

How to Avoid Transit Fees?

Building an onshore gas pipeline requires transit fees. In order to transport gas from Russia to Germany, it is necessary to build pipelines through Latvia, Lithuania, Poland and Ukraine. It is a well known fact that transit costs are high. How should this problem be solved? Build an offshore pipeline! Nord Stream is a pipeline composed of two tubes running through the Baltic Sea, transporting natural gas to Europe from Russia. These two pipelines, each of 1,224 km, are the most direct connection between the huge reserves of natural gas in Russia and the European Union energy markets. Approximately 55 billion cubic meters of natural gas per year will flow to corporate and private customers through both threads for at least 50 years. The construction of the first branch of

the pipeline began in April 2010 and ended in June 2011. Transportation of gas through this thread started in mid-November 2011. Construction of the second thread that is running parallel to the first line began in May 2011, and ended in April 2012. Transportation of gas through the second thread started in October 2012. Each thread has a capacity allowing to transport 27.5 billion cubic meters of gas per year. Building the pipeline was a significant event in the field of engineering. Due to the fact that it runs through the territorial waters of five states and may have an impact on other countries, a comprehensive process for granting permits was conducted as well as consultation.

An important element of this process was to focus on the environment and investigate potential risks connected with this project.

Another pipeline that is worth mentioning is South Stream. It is a planned gas pipeline with a capacity of 63 billion cubic meters, which will be built through the Black Sea, connecting the coast

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System which Rules South-Eastern Europe – Russian Gas Pipelines

Turkey 19%

24%

Italy France United Kingdom

11% 6% 6%

24% 10%

Other Western Europe Germany Eastern Europe

Fig. 2 – Share of Russia’s natural gas exports by destination, 2012 of Russia and Bulgaria. The construction of the South Stream pipeline will help Russia to reduce its dependence on transit countries of Central and Eastern Europe (Ukraine, Belarus, Poland).

The construction started in 2012 and is expected to be functional by 2018.

Gazprom Hegemony Company

(Bcf/d)

Gazprom

47.1

Rosneft

1.2

LUKoil

1.6

Surgutneftegaz

1.2

TNK-BP

1.3

Others

1.6

ITERA

1.2

Novatek

5.5

PSA operators

2.6

Total

63.4

Table 1 – Russia’s natural gas production by company, 2012

Gazprom Hegemony Referring to the preceding paragraphs and as Fig. 5 shows, attention must be paid to the com-

pany which manages most of the gas pipelines in Russia. Gazprom, a Russian state-owned company, the world's largest extractor of natural gas, produces about 74% of Russia’s total natural gas output. Moreover, the company controls most of gas reserves. More than 65% of proven reserves are controlled directly by Gazprom, which possesses the largest gas transport system in the world, with 158,200 km of gas trunk lines. With the support of Russian authorities, Gazprom is seeking to increase its economic position among the EU countries by engaging in joint projects of European gas companies. The highest state officials in Moscow have a significant impact on this group. Gazprom is very active in many areas. It holds shares in a number of German companies.

Gazprom has become a part of the Nord Stream consortium, which is building the Nord Stream pipeline. It has formed a partnership with the Italian concern Eni. In June 2008, as a result of record-high energy prices, Gazprom's market value amounted to $342 billion. Gazprom was thus the third corporation in the world in terms of market value, after ExxonMobil and PetroChina. Alexander Medvedev, vice president of the group, announced the capitalization of $1 trillion in 2014, but due to the decrease in trading on the Moscow stock exchange after fleeing of Western investors following the Russian-Georgian war in August 2008, and also

Radosław Budzowski

due to lower prices of oil and gas resulting from global economic crisis capitalization of the group fell to $85 billion at the end of 2008 and remained at this level in the first quarter of 2009, which gave it 35. place on the list of the largest companies in terms of capitalization in the world.

Ukraine – a Key Link This winter the situation in Ukraine shook the whole Europe. Much was said about the po-

43

flows to Europe from Ukraine. This amount has decreased dramatically over the last years. In January 2008, before the launch of the Nord Stream pipeline, the transit reached 390 million cubic meters per day. The largest pipelines lead to Slovakia and Romania, the smaller ones – to Poland and Hungary. Ukraine produces about 20 billion cubic meters of gas annually and still needs about 40 billion. So far Ukraine used the resources from Russia. In 2013, the price of Russian gas was $400 per 1000 cubic meters. In the fourth quarter of 2013 Ukrainians stopped buying gas from Gazprom for

Fig. 3 – The Trans-Siberian Pipeline litical aspects of the conflict, but the importance of Ukraine as a transit country is also worth considering. Ukraine has the world's largest transit pipeline system, managed by state-owned Naftohaz. The system receives gas from the East, Russia and Central Asia, and sends it to Central Europe and the Balkans. Ukrainian system is able to take 288 billion cubic meters of gas per y ear, while its annual export capacities account for 142 billion cubic meters.

This difference results from the presence of a large gas pipeline in the east of the country that sends gas from northern Russia to the south of the country.

More than 200 million cubic meters of gas per day

a few days, claiming that they have financial problems. The country, which is most dependent on Russian gas transit through Ukraine is Bulgaria, which buys this way 100% of natural gas. Slovakia imports two-thirds of the gas, Greece more than a half of its demand and the Czech Republic – 80%. Czechs can receive gas through Nord Stream which bypasses Ukraine. Over the years Ukraine resisted to Gazprom, which wanted to take control of its pipelines. As a result, the Russians decided on two very expensive projects (Nord Stream and South Stream) that make Russia less dependent on the Ukrainian transit. The price they are willing to pay for it provides the estimated cost of the latter project – about $35 billion.

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System which Rules South-Eastern Europe – Russian Gas Pipelines

Fig. 4 – Comparison of capacity of different routes

Conclusion It is impossible to describe all important Russian pipelines in such a short article, especially these that are planned to be built. As you can see, Russia seeks to maximize independence in terms of gas exports. Conflictual relationships between Russia and transit countries have repeatedly threatened to disrupt gas supplies to Europe.

Do the Western Europe countries have to be wor-

ried about their gas imports? It is difficult answer this question. However, European countries have more and more opportunities to import gas, e.g. from Algeria and Norway (where Statoil sold more gas to Europe in 2012 than Gazprom).

Due to the conflict between Ukraine and Russia, one thing is certain: geopolitical tensions always have a strong influence on energy markets, making oil and gas prices instable… Nevertheless, it is Russia that holds all the cards. 

References 1. (2013, November 12). World Energy Outlook 2013. International Energy Agency.

2. Gazprom. (2012, December 31 ). Production. About Gazprom. Retrieved February 8, 2014, from http://www.gazprom.com/about/production 3. Mathonniere, J. (2014. March 10). The end of Russian gas hegemony? Student Energy Blog. Retrieved February 9, 2014, from http://studentenergy.org/blog/the-end-of-russian-gas-hegemony/ 4. Nord Stream. (2013). The pipeline. Retrieved February 8, 2014, from http://www.nord-stream.com/ pipeline 5. Nord Stream. (2013, December). Transporting Russian Natural Gas to Western Europe. Nord Stream Library. Retrieved February 8, 2014, from https://www.nord-stream.com/press-info/library/ 6. Pirani, S. (2009). Russian and CIS Gas Markets and Their Impact on Europe. Oxford, UK: Oxford University Press.

7. U.S. Energy Information Administration. (2013, November 26). Russia. Analysis. Retrieved February 8, 2014, from http://www.eia.gov/countries/cab.cfm?fips=RS 8. Wyciszkiewicz, E. (2009, January 1). Geopolitics of Pipelines. Energy Interdependence and Inter-State Relations in the Post-Soviet Area.

Photos: eia.gov, theguardian.com, istockphoto.com, svaboda.org

45

Joanna Wilaszek

conference | East Meets West Congress – Anniversary Edition

´´ Five Years of a Great Experience!

Joanna Wilaszek “East meets West” 2014 went down in history. For the 5th time it was a wonderful feast of knowledge, ideas, breaking boarders and building bridges between nations and generations.

We were happy to host over 400 guests coming from 32 countries, situated on 6 continents!

Student participants represented 38 universities and we had pleasure to meet representatives of 21 well-known international E&P companies.

During the student contests, we could see 41 research works, chosen from 164 applications.

All three congress days were a priceless occasion to get to know what is happening in the world of science and industry, meet new great people,

exchange opinions and discuss. Discuss what?

The matters of industry, education, science, technology – the matters of life. All that in the heart of Krakow, organized by AGH UST SPE Student Chapter.

Pre-day Traditionally, one day before the congress all participants had a possibility to participate in a wide range of networking events and workshops.

This year our friends from Gubkin SPE Student Chapter from Moscow organized PetroOlypmic Games – a contest during which student teams answered questions concerning petroleum industry.

Apart from this student participants took part in City Game, which gave all of them a great opportunity to visit the most marvelous parts of Krakow.

The Game was finished with an Icebreaker party.

1st day – OPENING! Opening ceremony was started by Con Fuoco Choir, which gave us a wonderful concert.

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Five Years of a Great Experience!

Afterwards we could listen to speeches of AGH University authorities: Vice-Rector – Professor Andrzej Tytko and Dean of the Drilling, Oil and Gas Faculty – Professor Andrzej Gonet, as well as the speech of the Manager of Young Members Programmes of SPE – Maria Zenon. After this part all supporters, both companies and institutions, as well as individual persons, whose help was priceless for organizing and development of the Congress, was awarded with statues. After the Opening Ceremony we have started a panel which every student was waiting for: Career Session.

During the panel, representatives of the companies which became sponsors presented their offer for students. The opening day was fulfilled with the Social Opening Gala organized in Hilton Garden Inn Hotel.

into 3 parts and each of them had its own moderator – distinguished guest, specialist in the presentations’ categories. Every moderator opened his part with a speech focusing on his career and afterwards students presented their research works.

The distinguished guests, who became moderators of Student Paper Contest were: Gerhard Milan (OMV), Milton Jerez (ConocoPhillips) and Carsten Simms (Weatherford). During the Paper Contest, we could see 21 presentations prepared by the most outstanding students from 15 countries. In the evening all participants were invited for dinner in Kompania Kuflowa “Pod Wawelem” Restaurant, were they could try delicious dishes, get to know a lot about Polish treat and all that just next to the Wawel castle – as the name of the restaurant says.

2nd day – Students’ beginning!

3rd day – Final emotions

The second day of the Congress was a day of two panels: Student Paper Contest and Distinguished Guests Panel. This year both of them were connected. Student Paper Contest was divided

During the 3rd day, finally it came time for the second student contest – Student Poster Session.

Its participants, coming from 14 countries, presented 20 posters. Every poster referred to one of the six categories (Drilling Engineering; Reservoir Engineering; Geology and Geophysics; Fuels and

47

Joanna Wilaszek

Energy; Health, Safety and Environment; Management and Economics). After the Poster Session we have participated in fascinating Oxford Debate, prepared by Young Professionals Section. The topic was “Is higher education necessary for a career in high-tech industry?”. After the lunch break we took part in Closing Ceremony, during which results of the Student Contests were announced. We would like to congratulate the winners!

The winners of East meets West 2014 Student Paper Contest 1 place: Daniel Sanchez Rivera (The University of Texas at Austin, USA) “Reservoir Simulation and Optimization of CO 2 Huff-and-Puff Operations and Application of Mortar Coupling to Hydraulic Fracture Models” st

2 nd place: Lukas Jakob Mosser, Fabian Steinacher (Montan University of Leoben, Austria) “Impact of gas oil gravity drainage on the flow behaviour in a Moroccan carbonate anticline” 3 rd place: Carter Henderson (Texas A&M University, USA) “Integrated Workflow to Forecast and Maximize Liquid Yield Obtained Over the Life of a Gas Field” Commendation: Alsu Gabbasova (Gubkin Russian State University of Oil and Gas, Russia) “Control of Oil Stability towards Asphaltene Precipitation by Bioadditives”

The winners of East meets West 2014 Student Poster Session 1 st place: Alina Malinowska, Patrycja Pęczek (AGH University of Science and Technology, Poland) “Various vegetable products as natural organic sorbents for oil spills removal” 2 nd place: Johannes Loisl (University of Vienna, Austria) “High-resolution seismic reflection data acquisition on the Neusiedlersee, Austria” 3 rd place: Anastasiya Kirichenko, Anton Zaytsev (Gubkin Russian State University of Oil and Gas, Russia) “Calculations for an optimum geometry of the Above-Bit Ejector Unit” Commendation: Ali Elaal (The British University in Egypt, Egypt) “Future trends in EEOR (Nano EEOR)”

Workshops This year “East meets West” gave all its participants to improve their skills. During the congress, three companies organized workshops. ConocoPhillips was the first one – the workshop was a great portion of knowledge for students of drilling and exploitation subjects. The topic was “Practical safety management on an onshore well location.”

The two other workshops prepared students from theoretical and practical point of view to the future

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job interview. The first one was prepared by specialists from Fair Recruitment company and the second one by specialists from Weatheford company.

Something about your career All students could get much more from “East meets West”. Simultaneously to all the panels and sessions, for the three congress days there was open Career Expo with stands of companies which were strategic partners of the Congress: OMV, Weatherford, Schlumberger, United Oilfield Services, ORLEN Upstream. Students had a unique opportunity to talk to the companies’ rep-

Five Years of a Great Experience!

resentatives, learn about the companies’ offer and put their CVs. Apart from this, three companies hold recruitment sessions, recruiting both for job and for internships.

See you next year!

What more can I say? Thank you very much for all participants, you have created the magic of “East meets West” together with us. See you next year, during the 6th edition of the Congress, which will take place from 22nd to 24th of April 2015! You can’t miss it! 

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Filip Krunić

conference | Annual Student Energy Conference

´´ The Annual Student Energy Coneference 2014 Filip Krunić The Annual Student Energy Conference 2014 was held from 5th to 9th of March 2014, at the University of Zagreb in Croatia. It covered a wide range of topics related to energy and the Oil & Gas Industry, what is more it was Croatia’s first ever international student energy conference.

ed students and young professionals as well as 30 experienced professionals who are experts in the Oil & Gas Industry with extensive national and international experience. Attending students were from all over the world: Austria, Azerbaijan, Croatia, Egypt, Iran, Lebanon, Kazakhstan, Hungary, Germany, Poland and Syria.

The Conference was entirely organized by the members of the University of Zagreb SPE Student Chapter. I am very proud to be the President of the Chapter, the founder of the Conference and the Main Organizer behind the event. It was a lot of work but it was all worth it when I saw how successful everything was. I hereby wish to thank all the co-organizers, our supporters and most importantly, all attendees without whom this event would not be successful.

During the opening ceremony, there were several distinguished speakers: Vice Rector for Research and Technology at the University of Zagreb (Melita Kovačević); Vice Dean for Science and International Cooperation at the Faculty of Mining Geology & Petroleum Engineering (Sibila Borojević-Šoštarić); and the Secretary of the Croatian Committee of the World Petroleum Council (Biserka Cimeša).

The Conference had amazing attendance for a first-time event. There were over 150 accredit-

They all praised the event and were proud, that such a significant and successful event was organized solely by students.

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There was an almost distribution of professional and student presenters. They have covered a wide range of topics concerning energy and various technologies in the Oil & Gas Industry. I have to say that we were very happy to receive a huge number of interesting paper abstracts from students and it was not easy to choose which one should be presented.

Apart from attending presentations session, attendees had an opportunity to tour Croatia’s wonderful capital City of Zagreb, Croatia’s world-famous Natural Park “Plitvice Lakes”, the Historical Gold Mine “Zrinski” and last but not least, there was a party every night! The conference was officially supported by the University of Zagreb and its Faculty of Mining, Geology & Petroleum Engineering as well as companies and organizations from the Oil & Gas Industry: oil company – INA (member of MOL group); the Croatian Underground Gas Storage Operator – PSP; SPE Croatian Section and the Croatian Committee of the World Petroleum Council.

The Annual Student Energy Coneference 2014

YoungPetro was the event’s Media Patron and also provided copies of the latest magazine issue to attendees.

Lastly, here are several photographs from the event. The most interesting is a photo from the closing ceremony, which shows the Organizers dressed in traditional mining uniforms, a famous trademark in the University and also common in several other countries. The attendees were so amazed by the uniforms that they even wanted to dress themselves and take photos!

We have received nothing but praise and positive feedback from our attendees and our speakers.

That is why we plan to organize the Conference next year again and have big plans for the future! It will be even bigger, even better and even more fun.

You will be able to find out more information on our website (http://spes.rgn.hr/asec/) in a couple of months, so be sure to follow us there and on Facebook (http://facebook.com/spezg), and we hope to see you in Zagreb in 2015! 

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Jan Wypijewski

conference | International Scientific & Practical Conference

´´ In the Blink of an Eye Jan Wypijewski 6th International Scientific & Practical Conference – this fantastic event took place on the 20th and 21st of February 2014 and was organized by Kazakh – British Technical University SPE Student Chapter and Kazakh – British Technical University in the former capital of Kazakhstan: Almaty. The main topic of students' discussion was “Innovative development in oil and gas industry”. Of course, YoungPetro was the media partner of the whole Conference!

and Gas Faculty Mrs Zaure Bekmukhametova, Ph.D., Mr Marcus Hartland – Mahon from PSN Kazstroy and Mr William Abson from Maersk Oil. Both companies were the main sponsors of the Conference.

Day 1

After the opening ceremony, special guests presented their speeches. All participants were accustomed with the details about Maersk Oil's MITAS programme by Mr Shukhrat Mametov. I also found the lecture of Mr Herwig Ganz very interesting. Mr Herwig Ganz is a Shell's Geochemist in Bangalore, India.

KBTU is located in the former Kazakh Parliament which is one of the most impressive buildings in Almaty. It was established in 2000 with a patronage of British Prime Minister – Tony Blair.

After the Plenary Session and lunch all students headed to Paper Contest Session. It was divided into five sections connected with the topics such as: new technologies, geology and exploration,

The university is the most recognizable Kazakh university in the world.

environmental challenges, mechanics and mathematical modeling and social – economic problems. All participants showed their best sides and presented really innovative solutions for the industry. After the day full of attractions and fun all of us were invited to a ceremonial dinner.

The 6th International Scientific & Practical Conference was opened by Pro-Rector for Research at KBTU Mr Muarat Zhurinov, Dean of Energy, Oil

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In the Blink of an Eye

the closing ceremony Pro-Rector for Research at KBTU Mr Muarat Zhurinov awarded the best students who had won in the Paper Contest in their categories. After the official part, we all headed to Cosmo Leisure Center for a bowling game!

Day 2 The second day of the conference was no less attractive than the first one! We started from the presentations by company representatives called Petroleum Engineers' Presentations. What's important is the fact, that YoungPetro International Student Magazine had also its presentation! After lunch, some students took part in a Motivational Trainings “My way to professional career and Trends of Kazakhstan labor market for the young specialists,” the rest competed in Intellectual Petroleum Games. The quiz was very amusing and educative, the participants presented skills from a wide range of topics connected not only with engineering but also with politics or economy. The last event was the Roundtable talk between KBTU and industry representatives and students about the development of oil & gas industry. During

I strongly recommend all of you participation in the 7th International Scientific & Practical Conference the next year. Without any shadow of doubt, the organizers rose to the challenge! Everything was prepared excellently. You should also definitely stay a few days longer and go sightseeing in Almaty and take a trip to Tien Shan mountains! You will never forget these places. I would like to thank the organisers and all students with whom I had a pleasure to talk, these from KBTU and these from other Kazakh universities: KNTU, Aktobe and Nazarbayev. I will never forget your great hospitality, kindness and beautiful Kazakhstan! Spasibo bolshoe!  23-25 June 2014 | Dubai

Organised by:

www.iransummit.com

The high-level meeting will bring together experienced International Oil Companies (IOCs) in the Middle East along with world famous experts to discuss key opportunities for development of the Iranian oil and gas sector and highlighting areas for greater international co-operation, such as geology and infrastructure.

Our Esteemed Speaking Faculty Includes:

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Endorsed by:

Azizollah Ramazani, Manager of International Affairs, National Iranian Gas Company H.E. Dr. Hamid Reza Katouzian, President of Research Institute of Petroleum Industry, Ministry of Petroleum Dr. Kambiz Sadaghiani, CEO, Kayson Energy Company Dr. Mahdi Asali, Deputy of Research at IIES (Institute for International Energy Studies) and Advisor to Deputy of Petroleum Minister Dr. Alireza Bashari, Chairman of the Board Directors, ISPG (Iranian Society of Petroleum Geology Dr. Behrooz Akhlaghi, Attorney at Law, Senior Partner, Dr. Behrooz Akhlaghi & Associates Charity Partner:

Media Partner:

For more information contact: Ben Hillary E: BenH@irn-international.com T: +44 207 111 1615

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Rohit Pal

meeting | UPES SPE Fest 2014

´´ Pages from a Diary: India Rohit Pal As we just rounded up with the UPES SPE Fest 2014, I would like to share with you my pleasant experience of an amalgam of fun, knowledge, and interaction.

Held between 6th and 9th February 2014, University of Petroleum and Energy Studies (UPES) SPE Student Chapter welcomed more than 300 delegates under one roof – students from Indonesia, Kazakhstan, Nigeria, Saudi Arabia and all parts of India.

Day 0/Feb 5: We landed in one of the oldest cities in the country – Dehradun. After reaching our hotel that afternoon, we were informed about a couple of field trips scheduled for the day. The first was to Institute of Drilling Technology (IDT), ONGC, Dehradun, where the students witnessed an artificial blowout on a real rig. We were introduced to BOP simulator that belonged to the ONGC, the

national oil company of India, after which we took a round of the cement slurry laboratory. Later, we visited the ONGC Oil Museum that gave us an interface to the industry we belong to – a story that starts from exploration to production.

To create just the right ambience for the competition and getting to know each other, the organizers hosted a bonfire party in the evening with a lavish Indian dinner setting out one of the best performances by the participants. What a tiring, but great day it was!

“I was greatly motivated by the fest. The fest thought me how to serve the society through professionalism.”

Tauseef Mahmood, Al Habeeb College of Engineering & Technology, India

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Pages from a Diary: India

Day 1/Feb 6: Nestled in the mountain ranges of the Himalayas, UPES is located in the outskirts of the beautiful city of Dehradun. The fest started with the inaugural ceremony in the presence of the Chief Guest, Mr. Rich Paes, Director Operations, Cairn India Ltd and other delegates.

The preliminary rounds for the Symposium and Source Code took place with a huge number of participants. Various sessions of “Techuminati”

Day 2/Feb 7: We woke up early in the morning.

The cloudy weather couldn’t get better until heavy rains lashed the city. Conclave sessions consisted of the best scientific and experience sharing sessions I have attended so far. Anton Paar Workshops on "Virtuouso" – Poster Presentation also took place, where numerous participants displayed the latest on various topics from Drilling and Exploration, Reservoir and Production Un-

– the Paper Presentation competition – which is the flagship event of the fest started off with a great bang. Shortlisted abstracts had their authors presenting their papers to a panel of experienced industrialists. The Schlumberger Case Study – Fortune of a Star Trek, the most awaited competition, was also conducted parallely. Preliminary rounds of "Noesis" – Mega Quizzing event during the fest highlighted the day.

conventional Resources and Chemical & HSE.

“UPES SPE Fest was one of a kind. Noesis was really great! After attending the workshops by Schlumberger and Baker Hughes, I really felt there's a professional in myself and I'm lucky to be a part of the oil and gas industry.”

Ateeb Sharief, JNTU Hyderabad, India

The Indian Oil & Gas Career Expo & Exhibition (IOGCEE) was inaugurated by a panel of industrialists examining the various projects put up by the pre final year students of UPES. The visitors were given an insight on the oil and gas industry in India. The day was complemented with two really informative Anton Paar’ Workshops.

Day 3/Feb 8: We cruised over the terrains of Bidholi to reach the campus, to witness the Mud Challenge that we all awaited for. It was really great to see over 80 teams battling it out for the finals.

Enjoyable events like Treasure event, Snapshot (Photography Contest and Petrabol (Mini-Football tournament) gained a huge participation

Rohit Pal

among students. Schlumberger marked its presence at the fest by organizing one of the finest workshops for the students to learn more on rate analysis techniques, nodal analysis and inflow performance relationships. To rejuvenate our spirits, the Chapter hosted a Cultural Night late in the evening. That night we presented the audience a blend of cultures and colors of harmony and love between nations.

“This fest was a great experience! I loved my stay here in Dehradun, meeting new people and professionals!”

Gugulavath Suresh Naik, Kakinada

Day 4/Feb 9: Every possible technical event associated with our industry took place during this excellent fest. The most exciting finals of Noesis took the finalists to a rollercoaster streak of rounds. The

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Conclave sessions were to conclude today. The Baker Hughes Workshop was the icing of the cake.

The workshop was based on the artificial lift systems the company deploys all over the world in different scenarios. Definitely worth attending!

All good things have to come to an end. To put an end to the four day event, the Valedictory ceremony of the SPE Fest 2014 saw UPES keeping home the Champions Trophy and the prize distribution of the various events that took place. My stay in Dehradun has ended likewise.

I extend my warm regards and many thanks to the UPES SPE Chapter for the warm hospitality, excellent coordination and quality dedication that all the delegates enjoyed over the week. Hats off to the Organizers! Truly, it was an experience worth the miles for all the participants. UPES SPE Fest, undoubtedly, lived up to its tag: Vision. Venture.

Victory. 

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How it works

How it works?

Maciej Wawrzkowicz

Rocks that occur under huge masses of ocean water and its seabed may conceal abundant reservoirs of hydrocarbons. And we, as “people of oil and gas”, must know how to extract them. This is why I decided to write something about drillships. Of course, information presented in “How it works” of this issue will be only a tip of the iceberg, which is knowledge of these units used in order to exploration, drilling and hydrocarbon exploitation on the sea.

First of all – let’s think – why did the people started to seek for petroleum “offshore?” The answer is clear – to exploit more than they had been able to produce from wellbores located onshore. Innovation was accelerating not only by willingness to earn more but by growing demand for petroleum as well. Did you know that the first offshore drilling took place in 1897? Originator of this idea was H.L. Williams, who used the pier in the Santa Barbara Channel in California to support a land rig next to an existing field. Five years later, there were 150 offshore wells in the area. When this method of drilling on the sea became relatively popular people started to develop offshore drilling.

and transport staff. In order to drill, column called marine riser need to pass through the vessel’s moon pool and connect the outlet of the well with the bottom of the drillship.

The main advantage is possibility of drilling on very deep waters, from 610 to even 3,048 meters!

Moreover, drillships are completely independent, in contrast to semi-submersibles and jackup barges, which need to be transported by another units like seagoing tugs.

On the other hand, the major disadvantage is susceptibility to being agitated by waves, wind and currents. It is especially troublesome when the vessel is actually under drilling process, due to the drillship’s connection with equipment thousands of feet under the sea. This is why these kinds of units are equipped with the most sensitive mooring systems. Sometimes, especially on the shallower waters, drillships are moored to the seafloor with just a few anchors but when waters are deeper drilling vessels depend on dynamic positioning systems (DPS) – that I was describing in the previous issue – to keep the vessel in place while drilling.

In the early 1930s, the Texas Company developed the first mobile steel barges for drilling in the brackish coastal areas of the gulf. But the first serious drillship was the Cuss 1 created especially for Mohole project which was an ambitious attempt to drill through the Earth’s crust into the Mohorovičić discontinuity and was executed from 1961 to 1966. Fortunately, the collapse of these plans didn’t prevent fast-developing technology of the drilling vessels.

The world´s largest drillships are the Discoverer Enterprise, Discoverer Spirit and Discoverer Deep Seas, each of which displaces 103,000 tones.

The vessels are owned by Transocean Inc. (USA) and are capable of drilling in over 3,050 m of water, and to overall depths of 10,650 m. The ships are 255 m long and 38 m wide! By contrast, the most expensive drillship ever built is DrillMAX ICE constructed in South Korea.

Drillships have extensive mooring or positioning equipment, as well as a helipad to receive supplies

See you in the subsequent issue! Next time we will be talking about oil rigs! 

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AUTUMN / 2012

WINTER / SPRING / 2012

ISSN

2300-1259

SUMMER / 2013

ISSN

2300-1259

Call for Papers YoungPetro is waiting for your paper!

The topics of the papers should refer to: Drilling Engineering, Reservoir Engineering, Fuels and Energy, Geology and Geophysics, Environmental Protection, Management and Economics Papers should be sent to papers @ youngpetro.org For more information visit youngpetro.org/papers

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n a e m n o a c e e m B n o a c e e m B o c e B

r o d a s r s o a b d a m s A s a Amb counttrryy!! n r u u o try! o c y n r u u iin o o c y r n u in yo

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