No. 2, 2010
Yury Ikonnikov
,
Head of the Oil Production Department of LUKOIL
,
Robert Ramazanov
,
Head of Department for Service Work in Oil Production of LUKOIL
,
INNOVATIVE KEY TO THE SUBSOIL
LUKOIL-PERM is successfully introducing new technologies for developing hard-to-recover reserves of hydrocarbons
The Perm Territory is one of the traditional oil regions of Russia, where today about 2.5% of all the country's crude oil is produced. The structures of the hydrocarbon reserves in this "mature" oil region are inevitably becoming increasingly difficult, so, maintaining the production rates calls for a complex of advanced technologies to be applied. The recognized leader in this sphere is LUKOIL-PERM, which has managed, by competently applying methods for raising the oil recovery factor, to cut running costs substantially and to ensure a growth in the production volume at the Perm oil fields.
High-tech oil production
Thanks to implementation of geological engineering programs on the current declining reserves and active start-up of new production wells, LUKOIL managed, in 2009, not only to halt the drop in the average daily oil production on the territory of Russia, but also to increase it by 5,000 tons a day compared with 2008. The average oil yield of existing wells has, for the second year running, stayed firmly at the level of 10,500 tons a day. The Company's additional oil produced through application of methods to raise the oil recovery factor of reservoirs amounted to 23 million tons in 2009, or about 25% of the total produced. LUKOIL-PERM is a leading LUKOIL Group company in the application of high-tech oil recovery improvement.
Even though the Perm Territory has been providing oil for 80 years, LUKOIL's production here is not falling. In 2009, oil production in the region exceeded 12.1 million tons, this being approximately a 3.7% increase over 2008. A large part of this oil comes from the Batyrbaiskoye, Shagirtsko-Gozhanskoye, Moskudinskoye, Pavlovskoye and Unvinskoye fields. Overall, the company currently accounts for over 90% of the aggregate production in the Perm Territory, i.e., the total volume of oil produced since the first industrial flow of hydrocarbons.
It became possible to maintain high volumes of oil production, in spite of the deteriorating structure of the reserves, largely as a result of application of high-tech technologies.
As of the beginning of 2009, the LUKOIL-PERM group of enterprises has on its balance sheet 165 fields and promising structures. Of these, the remaining recoverable reserves of 90 fields amount to about 406 million tons.
Within the current structure of the remaining recoverable oil reserves, the proportion of reserves that are hard to recover has risen to 68%, the withdrawal rate of these reserves being only a third of that of active reserves. Fields in the 3rd and 4th stages of development account for over 70% of the remaining recoverable reserves concentrated in sectors with a low thickness and in water-oil and under-gas-cap zones. On development of 58% of the reserves, the current watercut of the output produced by LUKOIL-PERM Group enterprises amounts to 66%.
Hard-to-recover reserves include: highly viscous reserves in reservoirs with oils over 30 millipascal a second (16%); tight formations - reserves in formations with a permeability of less than 0.05 mkm2 (28%); others - reserves in wells with a watercut of over 80%, with low thickness efficiency - in terrigenous formations of less than 2 meters and carbonate formations of less than 4 meters (19%); and under-gas-cap reserves (5%).
Even though the majority of LUKOIL-PERM fields are in the third stage of development, in recent years the company has been actively raising its oil production volume, up to 20% of the annual total being provided by use of intensification technologies, including over 5% by new technologies. Hard-to-recover reserves make up a significant proportion of the total structure of reserves. They can only be handled efficiently by using new technologies that allow implementation of the company's strategic program envisaging an increase in the annual oil production to 14.1 million tons in 2019.
Most of the company's wells were sunk 20-30 years ago and this dictates the need for intensification of production. It is, therefore, very important for the purpose of rational subsoil use and full development of reserves, to find technologies that would allow a substantial increase, for an extensive period, in the well yield and an expansion of the drainage area of oil reserves.
Such methods include technologies capable of making development of a facility far more efficient. These are the deep-penetrative, most technologically complex physical methods for intensifying oil production and raising the oil recovery factor of formations, which have been developed actively in recent years, specifically: radial drilling, proppant and acid reservoir hydro-fracturing and drilling of sideholes in wells.
Intensification is the key
In recent years, the total number of new technologies for intensifying oil production and increasing the oil reservoir recovery factor has been rising annually and the resulting additional production in 2008 alone amounted to 688,000 tons of oil.
One of the latest technologies for raising the oil recovery factor of formations that has been used at LUKOIL-PERM fields since 2006 is radial drilling. Radial drilling technology consists of drilling, in vertical and inclined wells (up to 60 degrees incline from the vertical), long (up to 100 meters) channels in different directions and at different levels. Special nozzles are used for these operations (mills, jet nozzles), as well as coil tubing and a flexible, 100-meter long high-pressure hose. One example of successful radial drilling is provided by well No. 455 at the Ozernoye field, which had produced 2,286 tons of additional oil as of September 1, 2009.
The last four years have seen an annual increase in the volume of technology introduced and, in 2008, more than 90 jobs (well operations) were performed. In 2009, about 100 jobs were carried out. In total, during the period from 2006 to 2009, well operations totaled about 240.
During such operations, from two to six apertures were drilled in each well. As a result of analysis of the work performed, it was discovered that the increase in oil recovery tends to depend on both the number of apertures drilled and on the volume of the acidic solution pumped in. The small drop in the effectiveness of radial drilling in 2009 was due to the increase in the number of operations at productive formations with highly viscous oil.
Up until 2012, radial drilling technology will be applied mostly on productive formations with a carbonate type of collector at the Batyrbaiskoye, Pavlovskoye, Rassvetnoye and Shumovskoye fields. Subsequently, it is planned to increase the scale of introduction of a cheaper and more effective technology - drilling perforation at wells with hard-to-recover reserves.
The second technology successfully applied at LUKOIL-PERM fields is well hydro-fracturing (acid and proppant). In 2008, hydro-fracturing and acid hydro-fracturing were carried out in 67 wells and demonstrated a high level of effectiveness under different geological conditions. The volume of proppant pumped in at each well amounted to up to 40 tons. In 2008, for instance, the average rise in oil recovery reached 16.7 tons a day.
Within the scope of an agreement on monitoring LUKOIL-PERM fields, work was contracted with PermNIPIneft to provide scientific support for formation hydraulic fracturing using FracproPT and StimРlan hydro-dynamic formation fracturing stimulators, which helped improve the quality of the operations performed in the wells.
On the basis of the monitoring of development of the Churakovskoye field by PermNIPIneft, it was proposed to apply hydraulic fracturing at production well No. 350. As a result of this measure, the well produced an additional 57 tons of oil a day, totaling an additional 24,106 tons of oil as of September 2009.
Beginning from 2007, LUKOIL-PERM has annually increased the volume of ratholing. In 2008, 25 sideholes were drilled, resulting in an average increase in oil recovery of 19 tons a day. Using a geological hydro-dynamic model of the Unvinskoye field, calculations were made for drilling a sidehole at well No. 235 in order to bring undrainable reserves into production. This resulted in oil recovery of 24 tons a day, the total additional oil production as of October 2009 amounting to 4,852 thousand tons of oil.
Foreseeable prospects
Planning which uses calculations based on hydro-dynamic models and implementation of the program for pilot works between 2006 and 2009 provided for highly effective drilling of sideholes, hydro-fracturing and radial drilling. The overall oil recovery increase amounted to more than 14 tons a day.
The results of increasing the volume of work and disseminating experience to new facilities in 2009 confirmed the success of the selected technology solutions. New technologies for acid hydro-fracturing and radial drilling of channels in wells with a carbonate collector were introduced and proved highly effective, so it is planned to develop this work in the long run.
In the near future, it is planned to apply multilateral wells, transfer to industrial introduction of drilling perforators and develop experimental work on other technologies (chemical, hydro-dynamic and other methods).
The positive results of introducing new technologies mean that their industrial use at other LUKOIL-PERM fields can be planned for the purpose of bringing hard-to-recover reserves into production. The anticipated additional oil recovery from introduction of the new technologies will be over 3 million tons in 2012.
In 2010, LUKOIL-PERM plans to carry out pilot works on introduction of the technology of drilling multilateral wells and wells with a considerable horizontal extent. The advantage of the method is that it can raise the oil recovery level without drilling new wells. A rise in oil production on territories with environmental restrictions would thus not affect the environment. The drilling will be carried out by specialists from Eurasia Drilling Company and Baker Hughes.
This technology will be tried out on the Shagirtsko-Gozhanskoye field. If the tests are successful, LUKOIL-PERM plans, in 2011, to apply this technology for developing the Archangelsky field, located beneath the Verkhnekamskoye deposit of potassium salts (Usolsky District, Perm Territory). Drilling of multilateral wells will allow the company not only to implement design solutions and raise the formations oil recovery factor, but also halve investment in production drilling.
LUKOIL-PERM is constantly seeking and introducing new oil production technologies. This is dictated by both the complex specifics of the Perm area fields and a striving toward development and a steady rise in the level of oil production.
Effective use of the latest technologies will ensure that the Company will be able to maintain the volume of oil production in the Perm Territory at a high level for many years to come.
