Samotlor: Reawakening The Giant

A well pad in the Samotlor basin, West Siberia

«Not every oilman has a chance in his lifetime to work at an oil field like Samotlor», says Sergei Brezitsky, TNK-BP Executive Vice President for Upstream, who previously spent several years as head of the Samotlor business unit. «It was an honour for me to manage the development of Samotlor.  I realized that I was working at a legendary field that had raised several generations of oilmen, the best people in our profession. We have always fought for Samotlor and believed in its future».

Waves roll gently across the giant lake of Samotlor, whose name means «black lake» in Khanty, the language of the indigenous people of this region of Western Siberia. The name is apt, for beneath the waters, lies one of the world’s biggest oil fields.

Fishermen return every spring to the lake, which spans an area 11 kilometers long and seven kilometers wide. After a long absence, «the ducks are coming back again», proudly say old-timers – the pioneers who developed the field and built the nearby city of Nizhnevartovsk over the past 40 years.

When Samotlor was discovered by Soviet geologists in the 1960s, the remote area was densely covered with Siberian woodland, or taiga. Stretches of woods were interspersed with marshland with no firm ground. The pioneers of Samotlor had to lay down logs and sand to build roads. Heavy equipment was transported in winter when snow and ice provided natural strength for the makeshift roads.

Samotlor originally held a staggering 55 billion barrels of oil in place, earning it a unique place in the history of the international oil business. The first producing well was drilled in 1969. Eleven years later, in 1980, Samotlor reached its peak annual production of nearly 3.2 million barrels per day.  In the years which followed, Samotlor’s prolific «gusher» wells accounted for half of the country’s output and many believed the bonanza would last forever.

The crash came soon after the breakup of the Soviet Union in the early 1990s. This was a time when investment cash was short and the industry fell into neglect. Almost more damaging, people grew pessimistic. «It’s painful to remember how good, solid, five-storey apartment blocks stood deserted in the town of Raduzhny», says a Nizhnevartovsk oil executive, recalling the days when people left the area in droves, driven away by fears of poverty and unemployment.  In 1999, less than 20 years after its peak output, Samotlor production had plummeted to 400,000 bpd – a fraction of its former glory.

The rebirth of the Russian oil industry dates from 2000 when the country began to recover from the financial crisis of the late 90s, the oil price embarked on a steady upward trend, and the government promised more stability for investment than had been seen in the previous turbulent decade.

Jewel in the crown

When TNK-BP became operator of the field in 2003, it was clear that the company had inherited a jewel. However, it was badly in need of repair and renovation.

«Not every oilman has a chance in his lifetime to work at oil field like Samotlor», says Sergei Brezitsky, TNK-BP Executive Vice President for Upstream, who previously spent several years as head of the Samotlor business unit. «It was an honour for me to manage the development of Samotlor.  I realized that I was working at a legendary field that had raised several generations of oilmen, the best people in our profession. We have always fought for Samotlor and believed in its future».

A number of tasks demanded immediate resolution: stabilization of production volumes; optimization of the well stock and reactivation of idle wells; plus tackling an environmental legacy that was probably one of the worst in the Russian oil industry. These challenges all required the application of strategic investment and technologies.

Before 2005, Samotlor had been developed on the basis of design documents approved in 1993. But much had changed since the early 90s. Technological progress had brought a better understanding of the field’s remaining potential and offered new, more efficient ways for extracting oil.

TNK-BP spent three years studying the existing data and drew up new plans for Samotlor. One of the first rewards for this labour was the official approval given in September 2004 for the company’s updated reserve data. According to the latest calculation, Samotlor still holds more than 7 billion barrels of oil in place and around 100 billion cubic meters of gas, and ranks among the five largest fields in the world.

The updated reserve count helped to secure approval in December 2005 for a new enlarged development plan for the field. Around the same time, the company reached another milestone for the long-term planning and sustainability of its business by securing an extension of the Samotlor licence until 2038.

According to Nikolai Lissovsky, Chairman of the Central Reserve Commission of Rosnedra, Russia’s agency for subsoil use, «In 2005, the elaboration and approval of a united design document for all facilities and licence sections launched a new beginning in the development of the Samotlor oil field».

The new development plan outlines a work programme to be carried out until 2099 – the end of the century.

Under this plan, the existing well stock and certain specific exploration and technological activities will account for just over 70% of future production in the next 90 years. Other barrels will be contributed by access to new reserves via development of field extensions and application of advanced technologies.

Samotlor production since 1969 (mln bbl/year) 1980 — max. production 1.189 bln bbl

Forecast to 2011 (mln bbl/year)

«The main achievement under TNK-BP is that we have been able to revive people’s faith», Brezitsky says. «We have ensured sustainable production not only in these five years, but for many years to come, and made a considerable contribution to the development of the city of Nizhnevartovsk and the region».

Skill and innovation

So far Samotlor has been a litmus test for TNK-BP’s capabilities – and this call on the company’s technical and operational excellence is unlikely to diminish.

To invigorate and sustain the field after a period of heavy decline, Samotlor needs to benefit from the best practice that the company has accumulated through a combination of international experience built on a solid foundation of Russian oil industry expertise.

«New technologies are tested all the time. Samotlor is a testing ground for new equipment», Igor Tsykin, General Director of Samotlorneftegas, TNK-BP’s operating subsidiary for the field, says.

Samotlor pipeline replacement/modernisation, km

Nearly five years ago, when TNK-BP was formed, the focus of initial efforts was the implementation of improved well workovers. This called for a new two-pronged approach: the optimization of well hydrofracture stimulation; and improving the reliability of the electric subsurface pumps that facilitate about 70% of TNK-BP’s production.

These two initial measures had a significant impact on production rates and reserves capture.  Since TNK-BP has been working at Samotlor, the field’s production has increased by almost 33%, reaching nearly 600,000 bpd in 2007. In the next five years, output from the field should remain on this plateau, despite increasing natural decline rates in its very mature reservoirs. Investment into «keeping the Samotlor engine running» will amount to an annual $1 billion in 2007—2011.

Reconfiguration

Production at Samotlor has been underway for nearly four decades. As a result, parts of the field had become flooded with water and were inefficient. In many locations, large volumes of water were being pumped into the reservoir, but relatively little oil was being displaced.

In all water flood operations there comes a point where you need to consider «pattern reconfiguration». This is a term widely used by TNK-BP technology experts. In practice, it means reorientating the injector and producing wells in addition to changing the amount of water being directed to different parts of the reservoir. This can have a significant impact on the recovery of oil. Samotlor, being a major asset, will remain an important focus for TNK-BP’s water flood management activities.

Samotlor land reclamation, hectares The acreage of polluted lands was reduced by 27% by the end of 2007.

Second chance

About three years ago the company launched the application of another technology – sidetracking – which has also now been scaled up. This process entails reentering an existing well (often utilising part of the company’s idle well stock) and drilling out at side-angles into the reservoir to free up more oil. It’s an economic way to access new reservoirs in previously developed areas.

There are many idle wells at Samotlor – a legacy of the 1980s and 90s when scores of producing wells were abandoned due to a shortage of human and financial resources. Since late 2003, TNK-BP experts have recompleted more than 1,250 idle wells. To highlight the importance of this activity, suffice it to say that the reactivation of 750 idle wells has recently given the company access to 81.6 million barrels of proved reserves.

A key challenge has been to pinpoint where to drill to find new reserves in sections of the field which had previously been considered depleted. TNK-BP has established an algorithm to generate a list of potential sidetrack locations. The work is done in close cooperation by the company’s Technology and Upstream divisions, bringing together scientific analysis and international technical knowledge with a wealth of practical Russian expertise.

Upstream and Technology teams pull together production data, reservoir and geological models and the views and opinions of specialists who know and understand the behavior of the field. Then a list of candidates for well locations is agreed and prioritized. After drilling each well, the experience learnt is used to augment the company’s knowledge base.

One potential problem with sidetracking is that a sidetrack can sometimes move beyond the targeted zone, and enter a zone with high water content or low quality rock. This has been mitigated at Samotlor by the enhanced use of geosteering. Geosteering is a technique which allows the drill to avoid uneconomic zones and to accurately reach thinner oil-bearing zones. The accuracy and precision of drilling is greatly increased.

Visionaries

TNK-BP is using 3D seismic to help it improve its understanding of the magnitude and complexity of Samotlor.

In the course of a two-year programme, planned to be completed in 2009, 3D seismic will cover 4,000 square kilometers of the Samotlor licence area.

Application of this technology has not only significantly improved the success rate of development drilling. There are accumulations of oil at Samotlor that can now be visualized through the use of 3D seismic. These areas are called «four-way closures» or «satellite structures». They are close to the main field and close to the infrastructure – so again, the company can access them relatively inexpensively.

TNK-BP exploration teams have delivered high success rates in drilling satellite structures, which has resulted in finding new reserves and delivering high productivity wells.

«We have had what I would call successive waves of technology, starting with well work; progressing into water flooding; sidetracking; and now drilling four-way closures», says Francis Sommer, TNK-BP Vice President for Production Technology. «We are also looking at future applications of other technologies, like, perhaps, coil tubing drilling and radial drilling. All this is significantly improving the recovery from Samotlor».  

3D seismic, coupled with extended-reach drilling, has successfully proved seven satellite structures close to the field. Five of these areas are under development, providing access to 60 million barrels of oil equivalent of proved reserves. The company has identified another nine satellite structures, and two more will be tested in 2008.

«I’m happy to watch the dynamics of the field’s development», Igor Oneshko, Deputy General Director of Samotlorneftegas, says. «There has been a steady flow of serious investment and an influx of professionals as a result. It is pleasing to see that good old traditions are being brought back to life – first of all being attention to people, young specialists, for example».

Samotlor now employs 18,000 people. Today, all areas of the vast field have work stations with hot and cold water; separate changing rooms for dirty and clean clothes; autonomous power generators and heating facilities.

Some of these items may seem mundane, but in Siberia’s extreme winter cold, they can be hugely significant. Three years ago, temperatures at Samotlor fell as low as minus 57 degrees Celsius but the field continued to produce crude.

The oil pioneers who came to develop the field and stayed to build Nizhnevartovsk – which a local poet called «a capital of people’s fortitude» – remain passionately attached to Samotlor. It is a unique field, capable of producing crude for another 90 years or more, and whose full potential has yet to be discovered. For the oil men and women that work there, it holds a special place.

«It’s best to fly to Samotlor in the daytime», a senior TNK-BP executive says. «You can see an intricate web of rivers, ponds and stretches of woodland – like a huge French impressionist painting».

Ust-Vakh

Ust-Vakh has been one of Samotlor’s greatest successes as a satellite structure. The area is located on both banks of the Vakh river in the heart of the Samotlor acreage. Drilling began in 2002 on the right bank and in 2004—2005 was extended to the left bank. TNK-BP used an innovative design solution to conduct drilling activities in a flooded area of the Vakh river that had not previously been considered viable due to technological and environmental risks.

From scratch, it was developed using best practice, including 3D seismic, new drilling techniques, new hydrodynamic models of the Ust-Vakh area and the application of unique know-how in building a pipeline under the Vakh river.

Construction of the pipeline involved the use of a technology called «pipe-in-pipe». TNK-BP teams drilled directly under the riverbed, made an intentionally deviated borehole and then laid the pipe down through the hole.

Development of the Ust-Vakh acreage also called for the construction of a large enclosed electric substation – the first of its kind in Siberia – and unique crossings of power lines across the Vakh river. The project utilizes zero-discharge production technology, minimizing the environmental footprint. 

«Ust-Vakh was developed with technologies which had never been used before, not only in Russia but sometimes globally», Igor Tsykin, General Director of Samotlorneftegas, says.

In less than five years, Ust-Vakh has yielded more than 46.5 million barrels of crude, which has required investment of over $450 million. It is now in the third and final stage of development and is set to produce an additional 100 million barrels.

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  Samotlor: Reawakening The Giant (2,54 МБ)