The Gazprom Neft Joint Scientific and Research Centre, as part of a consortium of leading Russian academic institutions*, has completed its adaptation of a unique technology for well-core (formation sample) analysis on the strata of the Bazhenov formation**, revealing new properties of the underlying rock in non-traditional reserves, and increasing exactitude in forecasting oil-bearing capacity.
This research has been undertaken as part of a Federal Programme involving the comprehensive investigation of the Bazhenov formation.
New technology used in measuring the thermal properties of rocks has significantly increased the extent of investigations that can be made into the physical and filtration (fluid loss) properties of the well core. Its use has demonstrated that the thermo-physical (heat transference) properties of the Bazhenov formation correlate to the content of the organic matter therein; consequently, the availability of data on the measurement of such thermal properties makes possible the more accurate forecasting of the distribution of hydrocarbons within the strata of the Bazhenov formation.
Investigations have involved the examination of rock samples, collected over recent years at those Gazprom Neft fields at which investigations into the Bazhenov formation have been ongoing. Thanks to testing of this new technology it has been possible to establish a unique databank on the thermo-physical properties of the Bazhenov formation at Gazprom Neft, unparalleled anywhere in the world in terms of its extent and exactitude. Specialists at the Gazprom Neft Joint Scientific and Research Centre, in collaboration with their consortium colleagues, are now analysing the data obtained in order to more effectively forecast reserves at the Bazhenov formation.
Work on non-traditional reserves - including those of the Bazhenov formation - is a core strategic objective for Gazprom Neft, with new technologies directed at improving operations with non-traditional reserves being developed and adapted as part of the company's Technology Strategy. The consortium of which the Gazprom Neft Joint Scientific and Technology Centre is part is currently involved in a Federal Programme investigating the Bazhenov formation. Apart from their work on the well core, consortium partners are also testing new fracking technologies, investigating alternative enhanced oil recovery techniques, and developing three-dimensional geological, hydro-dynamic and geo-mechanical computer models of the strata, as well as developing methodological recommendations on technologies to be used in the evaluation of reserves, and their development.
Gazprom Neft is currently implementing two pilot projects directed at investigating the Bazhenov formation in the Khanty-Mansi Autonomous Okrug: at the Palyanovsky deposit in the Krasnoleninskiy field, and at the Yuzhno-Priobskoye field. Eleven directional and low-angle wells have been drilled at these fields in order to assess the potential of non-traditional reserves, and hydraulic fracturing (fracking) of the strata undertaken, with oil inflow obtained. These operations have allowed the potential for the commercial development of the Bazhenov formation to be confirmed and the potential for isolated fracturing to be assessed, allowing progression to an assessment of the effectiveness of basic production technologies - the drilling of horizontal wells with multi-stage fracking. Two wells (with a horizontal shaft running to a total length of 1,000 metres) have been drilled at the Palyanovskoye project, and drilling and completion technologies developed, with various designs for well-finishing with a cement casing being tested in fracking operations.
Gazprom Neft commenced its first project on the study of the Bazhenov formation in the Yamalo-Nenets Autonomous Okrug in late 2015, with fracking operations on Bazhenov deposits undertaken at the Vyngayakhinskoye field via one new appraisal and two directional wells, and oil inflow being achieved at all wells. An appraisal well was drilled for sampling and well-core analysis, and an extensive range of geophysical information recorded for detailed examination of the drill core and development of a geological model. The results obtained will form the basis for further work on evaluating effectiveness and the further confirmation of key technologies for development - the development of horizontal wells and multi-stage fracking.
* The consortium investigating the Bazhenov formation includes the Engineering Centre of the Moscow Institute of Physics and Technology, the Geology Faculty of Moscow State University, the Gubkin Russian State Oil and Gas University, and the Skolkovo Institute of Science and Technology (Skoltech). The Gazprom Neft Joint Scientific and Research Centre is acting as industrial partner in this project, as well as participating in the co-financing of the research programme.
** The "Bazhenov formation" refers to a specific geological stratum identified in the centre of Western Siberia, running to depths of 2,000-3,000 metres. Estimates suggest that oil reserves at the Bazhenov reservoir could amount to as much as 100-170 billion tonnes in Western Siberia alone. The stratum covers an area of approximately one million square kilometres and is 10-100 metres thick. The Bazhenov formation is classified as containing "hard-to-recover" reserves, development of which currently awaits the selection of technological solutions for its full-scale development.