Sergo Ordzhonikidze Russian State Geological Prospecting Institute, Moscow, Russia:

V. Yu. Kerimov, Pro-Rector for Science, Professor, Doctor of Geologo-Mineralogical Sciences
R. N. Mustaev, Head of Department for Basic and Applied Research, Associate Professor, Candidate of Geologo-Mineralogical Sciences, mustaevrn@mgri-rggru.ru
A. Kh. Shakhverdiev, Professor, Doctor of Engineering Sciences

Lomonosov Moscow State University, Moscow, Russia:

V. A. Zaitsev, Associate Professor, Candidate of Geologo-Mineralogical Sciences

The complex structure of the shelf in the Sea of Okhotsk, high geodynamic activity and the nonanticline traps present in the productive formations necessitate application of special technologies to studying secondary poroperm properties of the reservoirs. Prediction of locations and directions of open fractures is complicated by their small sizes. They are so small that fall beyond the detection range of many common tools such as well logging and seismic surveillance. Seismic detection of fracturing is impossible as a matter of principle; yet some logging tools of high resolving capacity can detect fractures under favorable conditions. When neither logging nor prospecting seismology can spot fractures, geomechanical modeling is often addresses as an efficient technique. Geomechanical modeling allows predicting effective porosity and permeability in the interwell space. As a result of the implemented studies, it is found that Sakhalin Shelf within the Kirin, Ayash and East Odoptu license areas experiences the modern shear stress with the sub-latitudinally oriented axis of maximum compression. The loading results in displacement along the existing discontinuities (faults), which generates a local stress field. The latter initiates new fractures or changes opening of the existing fractures which govern secondary porosity and permeability of rocks. 3D geomechanical modeling of this region made it possible to estimate permeability of each stratigraphical horizon. The revealed secondary permeability differs essentially in the upper and lower stratigraphical horizons, and the interface is the oktubai clayey rock unit. It is important that the contribution of the secondary permeability to the total (or effective) permeability is dissimilar in different stratigraphical units. The revealed secondary permeability essentially replenishes information on deliverability of reservoirs. The obtained data are applicable in hydrodynamic modeling.

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