No. 4, 2011

Natalia Solovyova


LUKOIL-PERM takes lead in geological exploration and high technology

One of the main tasks facing the geological service of LUKOIL-PERM is to maintain the company's mineral resource base. Geological exploration is therefore focused on selecting the most promising areas based on perceptions of the area's geological structure, research results and degree of exploration maturity. Over the last 10 years, the company has discovered 40 oil fields with reserves of over 26 million tons. The planned increase in oil reserves by 2020 shall be 159 million tons and in 3 resources - 46 million tons, respectively.

Time for new discoveries

It is over 80 years since the first oil was discovered in the Kama region, which is now one of the most thoroughly geologically explored territories. Indeed, the geological map of Perm Territory shows that it is literally permeated by oil fields associated with the Kama-Kinel system of depressions stretching from Bashkiria to the Northern Urals.

Research has shown that, in the Devonian, Carboniferous and Permian oil- and gas-bearing series, there remain quite a few hydrocarbon occurrences. These are small anticlinal traps missed by drilling or seismological surveys, as well as less studied traps of a nonanticlinal type. Under these conditions, the main focus is on improving structure treatment by applying new exploration methods. For instance, in the north of the territory, gravimetric studies coupled with 2D/3D seismics are effective for identification purposes, whereas, in the southern regions, the priority in further treatment attaches to seismological surveys coupled with structural parametric drilling. Since 2006, these methods have provided for highly reliable identification and treatment of small-scale and low-relief structures for prospect, evaluation and exploration drilling, and for discovering fields with reserves of about 1 million tons every year.

The effectiveness of the exploration methods applied may be assessed by analyzing data on uplift zone confirmation rate and well success ratio. Until 2006, for example, the uplift zone confirmation rate averaged 0.85 and the well success ratio did not exceed 70%. Over the last 5 years, however, when these methods have been used, the figures rose to 100%! The prospecting methods used provide for an annual reserve increment of over 5-6 million tons, with exploration efficiency standing at the level of 80 rubles per ton. In 2010, the exploration-induced reserve increment amounted to more than 13 million tons, this compensating by 110% for the oil produced.

As LUKOIL-PERM Deputy General Director for Geology Vadim Voevodkin explained, "LUKOIL has traditionally invested heavily in geological exploration, thereby maintaining its leadership among the other Russian private companies in this respect. Over the next few years, LUKOIL-PERM will spend some 1-1.2 billion rubles on exploration work. This means that the reserves increment will be maintained at a level at least equal that of oil production, which is rising by the year".

Not to rest on one's laurels is one of the rules followed by the company. The high indicators of geological exploration work merely testify to the need for further improvement of the prospecting and exploration complex. To this end, in 2011 experimental work has been carried out to apply the technology of low-frequency seismic exploration based on investigation of the micro-seismic background and providing an opportunity to forecast local fluid saturation features. In addition, considering the proportion of hard-to-recover reservoirs (over 60%) in the structure of remaining reserves, it is an urgent matter to improve geophysical well-logging methods for determining the fracture characteristics of the reservoirs and obtaining additional parameters relating to formation features and making reserve assessment more reliable through application of new core study methods. In 2010, the Company took the first azimuth-oriented core sample providing information about the spatial orientation of fractures.

Focusing on new technology

Considerable attention is still focused on development of seismic data processing and interpretation, higher forecast reliability and better seismo-geological model quality. Therefore, LUKOIL-PERM is actively cooperating with the LUKOIL-Engineering subsidiary PermNIPIneft in Perm, on the basis of which a Seismic Research Center is dynamically developing.

LUKOIL-PERM is systematically working to increase active reserves not only in proven oil-bearing areas but also promising new territories," comments Ekaterina Pyatunina, head of the geological exploration unit. "To this end, a long-term Geological Exploration Strategy has been developed and, over 10 years, this will produce an additional increase in resources in a volume of 50 million tons and in reserves - of about 160 million tons. The developed infrastructure will allow newly discovered fields and reservoirs to be brought rapidly into production and the volume of oil production increased. Unless new technologies are applied, however, the development target figures will not be achieved in the old oil region with its complex geological conditions".

The Perm Territory fields are mostly characterized by multizone reservoirs that, in accordance with modern reservoir engineering concepts, should be developed by independent well networks. Given the high proportion of undeveloped reserves among sites with low-yield reservoirs, the cost of production drilling needs to be cut.

In order to achieve this, LUKOIL-PERM has been drilling small-diameter wells since 2010. Slim hole (114 mm) sinking can be done from mobile drilling rigs, this greatly reducing the cost of production drilling by cutting the time needed for rig erection/dismantling preparatory operations. Cost cutting is also achieved by reducing well development expenditures, since work is being carried out at existing developed cluster sites with a collection system with the minimum necessary expansion of the land plot. Given lower initial well drilling and development of wells, low-yield oil reserves become profitable and are drawn into production. The company is planning to subsequently increase the number of such wells to 20 a year. This will help produce oil from noncommercial wells.

Another progressive drilling-in technique these days is horizontal well drilling, which has been the practice at Perm Territory fields for a long time now. To obtain a multifold increase in the oil flow rate by horizontal wells compared to ordinary ones, it is planned to use the multizone hydrofracturing method to bring hard-to-recover reserves into active development, raise development drilling efficiency by way of well stock reduction, expand the pay bed drainage zone and achieve a production increase. In 2012-2014, it is planned to carry out multizone hydrofracs at over 20 new wells brought into production drilling.

Pilot operations to introduce new production optimization methods envisage a stage-by-stage transfer from laboratory and on-site studies to experimental and then production work. One example of this is application of hydrofracturing, which is traditionally applied in all oil-bearing regions. In 2010, for instance, pilot operations with an incremental ultimate recovery of 19.4 thousand tons were carried out at 8 wells, including hydrofracturing using various breakdown agents, large-volume acid fracturing with an increased well-head pressure (70-100 MPa), as well as acid fracturing of horizontal wells. In 2011, it is planned to carry out pilot acid fracturing with a liquid loss regulator, fracturing using nitrogen, trial of acid fracturing using jet deflectors and liquid loss control systems.

Another traditional method used by the Perm oil producers is drilling of multibranch wells. The purpose of rat hole drilling is to improve methods for maximizing the development of recoverable reserves. One local task is drilling of such wells in reservoir buffer zones. The sinking of two side tracks from one of the wells on the Shagirtsko-Gozhanskoye field has doubled the well flow rate of an ordinary side track drilled under similar conditions. These processes are already included in development design documents. In 2011, for instance, they are planned to be used in upgrading one well on the Arkhangelskoye field by sinking 3 boreholes, two of which will be horizontal. This method is specific in that the existing main borehole of the well remains in operation.

Since oil was first discovered in Perm Territory in 1929, the subsoil is still sharing its "Black Gold" with the population. Not so willingly, of course, as during the first few years! Even so, the oil producers, geologists, developers and drillers have, during the interim, created new processes and technologies to enhance oil recovery and develop modern methods for maintaining the environmental balance, which makes it possible to increase proven reserves every year and compensate for the oil produced. After all, LUKOIL-PERM personnel have always relied on their professionalism, experience and team spirit. And these mean a lot when it comes to achieving common goals and fulfilling common tasks.

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Oil of Russia, No. 4, 2011
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