NEW DATA ON THE GEOLOGICAL STRUCTURE OF THE YURUBCHENO-TOKHOMSKAYA OIL-AND-GAS ACCUMULATION AREA AND WAYS OF FURTHER DEVELOPMENT OF ITS OIL-AND-GAS POTENTIAL

摘要

The Yurubcheno-Tokhomskaya oil-and-gas accumulation area (YTA) located in the western part of the Siberian platform (Fig. 1) was revealed in 1973 during drilling of K-1 Kuyumbinskaya parametric well. The well discovered a gas reservoir with the initial daily flow rate of about 200,000 cu m of gas under a unit of Vendian terrigene sediments in Riphean carbonate deposits. Further exploration resulted in delineation of a vast oil-and-gas accumulation area covering nearly 20 000 sq. km with main oil and gas reserves associated with Riphean and partly Vendian deposits. Of fifteen deep exploratory wells drilled on the Kuyumbinskaya area from 1973 to 1982 three wells flowed at commercial rates. First commercial oil flow rates were registered in K-9 and K-2 wells. In 1982 all operations on the Kuyumbinskaya area were ceased because of the low effectiveness of exploration. Local subdivisions of Roskomnedra (the Natural Resources Committee of Russia) failed to explore oil and gas reservoirs revealed on the Kuyumbinsky section of the YTA until the territory of the latter was licensed in 1996. Exploration was shifted to the Yurubchenskaya area where a field of the same name was discovered. Later, commercial inflows with flow rates of over 100 cu ma day were registered in the neighboring Vedreshevskaya, Nizhne-Tokhomskaya and Terek areas. As a result, a super-large area of accumulation of oil and gas reservoirs and fields with over a billion tons of indicated recoverable crude oil reserves and up to a trillion cubic meters of natural gas reserves was delineated [2].