Predyenisey Petroleum Subprovince—a New Prospective Target for Oil and Gas Exploration in Siberia

Kontorovich, A.E., Yu F. Filippov, L.M. Burshtein, V.A. Kontorovich, Institute of Petroleum Geology, Novosibirsk, Russia

The new Predyenisey subprovince, whose petroleum potential could be related to Upper Proterozoic-Paleozoic deposits, has been substantiated. Seismic exploration and deep drilling data allow prediction of a wide development of thick (to 10-12 km) Upper Proterozoic-Paleozoic sedimentary platform complexes, composed of the Riphean, Vendian, and Cambrian formations, similar in composition and degree of dislocation to the coeta­neous strata in the western part of the Siberian Platform. High petroleum prospects of pre-Mesozoic deposits were proved by direct oil indications. One of the ` `wells exhibits shows of oil which is similar in biomarker hydrocarbons to oils of the giant Yurubchen-Tokhomskoye field located in the western Siberian Platform. Geochemical studies of oil sam­ples in the accumulations and in formation waters proved that migration and accumulation of hydrocarbons, occurred first in the Paleozoic deposits of the left bank of the Yenisey River. Along with clear evidence of genetic relation of oil, identified in the section of one of the wells, to the marine high-carbonaceous strata, their chemical composition has some fea­tures, which indicate the Late Precambrian age of oil-generating deposits. The total volume of sedimentary filling of the Upper Proterozoic-Paleozoic sedimentary basin is above 2.2 million km3. The recoverable resources of the Predyenisey subprovince are tentatively esti­mated at 500-5000 million tons of oil, 900-9000 billion m3 of gas, and 5-60 million tons of condensate.