RESERVOIR IDENTIFICATION IN THE ATOVO HORIZON OF THE LOBER-MIDDLE BELAYA SUBFORMATION BASED ON WELL LOGGING DATA FROM DEEP WELLS

T. S. Mamakova, D. O. Mamakov, E. S. Zhuk

The Belaya formation extends throughout the Nepa-Botuoba anteclise and the Angara-Lena step. In the Lower-Middle Belaya Subformation there is the Atovo horizon (A12) composed of fractured and cavernous dolomites with anhydrite-dolomite and limestone interlayers. The horizon is poorly studied, and the criteria for drawing stratigraphic lines and estimating net thicknesses are undecided. The Atovo horizon potential was established in wells drilled in 1960 at the Atovsko-Balagankinskaya area from HC shows and qualitative indicators of reservoir properties. Current drilling results demonstrate that it is difficult to identify reservoirs in the Atovo horizon, so both application of direct qualitative, indirect and quantitative indicators and updating of well logging interpretation criteria are required.

Key words: Atovo horizon, porosity, Nepa-Botuoba anteclise, net thickness.

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