SOUTHERN BAIKAL REGION - A KEY SITE FOR THE STUDY OF OIL AND GAS-BEATING POTENTIAL OF THE FOREDEEPS IN THE SOUTH OF SIBERIAN PLATFORM
A. V. POSPEEV1, A. M. STANEVICH2, A. M. MAZUKABZOV2, A. G. VAKHROMEEV2
1Irkutsk Scientific Center SB RAS, 664033, Irkutsk, Lermontova str., 134, Russia
avp@ierp.ru
2Institute of the Earth’s Crust SB RAS, 664033, Irkutsk, Lermontova str., 128, Russia
stan@crust.irk.ru
Keywords: Южное Прибайкалье, краевые прогибы, ловушки углеводородов, байкальский трехчлен, мето дология нефтегазопоисковых исследований, Baykal region, hydrocarbons, rift formations, oil and gas potential, seismic, electromagnetics
Abstract
The Southern Baikal region is situated close to the industrially highly developed part of the Irkutsk region and the Republic of Buryatia, which therefore makes its oil and gas potential profoundly relevant. The lack of discovered large deposits of oil and gas here can be explained only by the extremely low level of exploration maturity of the geological structure and its complexity. Meanwhile, the existing favorable preconditions indicate the occurrence of hydrocarbon deposits in this area. These include the presence of marginal depressions, within which thickness of the subsalt clastic section tends to increase, as well as the distribution of Vendian-Cambrian carbonate reef formations. The study of Riphean deposits is of particular significance, as they form here many kilometers-thick intervals with enhanced reservoir properties. Caused by the lateral pressure of Baikal rift, an extended thrust structure developed at the marginal areas of the platform, to form a broad front encircling Patom Highlands. Here, both sediments of the upper overthrust structure and autochthonous rocks are considered highly potential for hydrocarbons. A pronounced dislocation of the upper part in the section of the platform margins re duces the quality of seismic data, which requires improving the methodology for oil and gas geological and geophysical prospecting. In this respect, the most appropriate appears the approach involving integration of seismic and electromagnetic studies, development of multi-wave seismic survey with large spacing and increased multiplicity factor, and the use of detailed geophysical data on the upper part of the structure for an adequate account of its irregularities. The paper shows that the development of the Southern Baikal region as a base region for the study of marginal basins in the south of the Siberian platform, will ultimately allow to assess its oil and gas potential and form a reliable methodological basis for the development of this kind of studies in the context of a similar geological structure of Cis-Patom and Cis-Sayan depressions.
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