TNK-BP Discusses Successful Approach to Exploiting Mature Fields
OREANDA-NEWS. March 31, 2010. TNK-BP executive vice-president for technology Francis Sommer discussed the firm’s successful approach to exploiting mature fields.
TNK-BP had impressive production growth last year at Orenburgneft, which operates your most mature fields. How did you achieve that?
Production from these fields was often aided by water injection, but many waterfloods were not optimised or became less optimised over time. Optimising water injection in these fields — by diverting water to areas that have not been swept or by strategic changes to injection rates across the field — has been one of the drivers. In addition, we have been able to identify a large number of near-field satellites through the use of modern 3D seismic. These accumulations vary in size from 2mn t to lOmn t, are close to existing infrastructure and are relatively easy to tie-in. This “brownfield exploration”, as we call it, has been an efficient way to boost production at our Orenburg fields. Beyond this, we have redesigned acid stimulations, forcing the acid to more efficiently clean up damaged perforations that can impair well productivity.
Does Orenburgneft have further growth potential?
Absolutely. Conventional wisdom holds that places such as Orenburg are mature and completely developed. But production growth of 6pc in an area that five years ago did not appear to have a bright future is an example of what can be done. We see further application of seismic and reservoir management technologies in this area, as well as continued improvements in well work. This is a part of our strategy across Russia — the application of select, new technologies and processes at mature fields, combined with efficient development of new fields such as Verkhnechonsk and Uvat.
Verkhnechonsk in east Siberia turned out to be more complicated than expected. What difficulties do you face?
Several things make Verkhnechonsk complicated. Firstly, the oil is cold, which brings production complications all the way from the wellbore to the surface pipeline system and the production facilities. The oil also contains a lot of heavy or so called waxy components that must be monitored for impacts on well and facility performance. Compounding this, the reservoir has high levels of salt within the rock matrix. This not only impacts the production chemistry, but also makes reservoir performance predictions difficult. Conventional approaches to even basic things such as petro-physics will not work well and more innovative solutions are required. So, it is the combination of complex fluids and difficult reservoir characterisation that make Verkhnechonsk quite a challenging development.
How are you overcoming these difficulties?
We continue to spend significant sums on obtaining surveillance information about the reservoir — for surface and subsurface. We believe this extra investment is critical to help us understand and resolve the key issues. We have already made great progress in understanding the chemistry of the oil and have developed a program to tackle the salt and wax. We have a promising new petrophysical model and have adopted an aggressive water injection program that will efficiently maintain pressure and displace oil towards the wells. And we have acquired new 3D seismic that has the potential to enable us to create a more detailed map of the geology between wells.
Overall, we have adopted an ambitious technological program to maximise production from Verkhnechonsk. Complex fields in remote locations such as Verkhnechonsk that require aggressive technology are costlier to develop. It is good that the government has recognised this. Without tax incentives, aggressive development of fields such as Verkhnechonsk would be less viable.
What are the main technological challenges at TNK-BP’s Yamal project?
The Yamal project is in the far north and covers a large area. It contains different fields with different types of oil — some light, some heavy — different geologies and different reservoir architectures. Transportation, roads and pipelines will require a lot of planning and will be costly, so we will be looking carefully at infrastructure technology. The plan is to use long-reach drilling to avoid building too many pads and drilling too many wells. This also minimises environmental impact, one of our core values. We are likely to use hydro-fracturing to stimulate tighter reservoirs into producing at commercial rates. For heavy oil zones, we will assess pro-ducibility through horizontal wells, multilateral wells and maybe the use of enhanced oil recovery (EOR) agents.
Are you talking about the Suzun and Tagul fields?
Development of Suzun will be a bit ahead of Tagul because Tagul appears a more complicated reservoir. The key issue at Suzun will be managing water injection and understanding the reservoir transition zones and boundaries. In Tagul, we expect to see heavy and light oil. Extracting this will require different technologies, and this could include alternative well-bore geometries and the introduction of EOR fluids.
What can you tell us about the nearby Messoyakh fields that TNK-BP co-owns with Gazpromneft?
This is an enormous area with great potential, but it is largely at the exploration and appraisal stage. We already know that the Messoyakh fields will be geologically complex and hold a mixture of light and heavy crude. We also see significant gas in the region. Mapping and clearly understanding the geology of these structures and testing the fluid contacts and pro-ducibility of the reservoirs across the region are the priorities.
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