About the Structure and Prospects for Oil and Gas Bearing of the Coastal Arctic Territories of East-ern Yakutia

Sitnikov V.S., Alekseev N.N., Arzhakov N.A., Obolkin A.P., Pavlova K.A., Sevostyanova R.F., Slepcova M.I.

The results of geological exploration work of the past years on the structure, geological development and prospects of oil and gas potential of the northeastern territories of the Republic of Sakha (Yakutia) are summarized and analyzed. The available data on the geological and geophysical study of each of the prospective areas are systematized. There is a certain continuity in the development of scientific ideas. At the present stage, the main directions of geological exploration remain practically the same as in the middle of the last century. This is mainly coastal and intermountain depressions and deflections (Primorskaya, Tastakhskaya, Zyryanskaya, etc.), within which the total thickness of meso-Cenozoic deposits reaches 2 km or more. Taking into account the results of studying these deposits in natural outcrops in areas adjacent to the onboard parts of these depressions, the presence of terrigenous reservoir horizons with sufficiently high filtration and capacitance properties and overlapping substantially clayey strata - the shields - is predicted within the sedimentary cover. It is indicated that an additional role in the increase of hydrogeological closure of the earth's interior is played here, perhaps, by the fact of the presence and widespread development of a thick layer of permafrost in the upper part of the section. According to the results of geophysical studies, traps of various types have been detected, including traditional anticlinal structures with elements of tectonic and lithologic screening, traps associated with manifestations of thrust tectonics, non-anticlinal traps, etc. For the first time, the question is raised about the potential petroleum potential of Paleozoic carbonate and terrigenous deposits, which are accessible for deep drilling in the Kolyma-Indigir interfluve within the zone of the Prikolymskie uplifts. It was confirmed that all coastal depressions of different sizes are open to the north towards the East Siberian Sea and are developed mainly on its shelf, where the prevailing part of the initial geological resources of hydrocarbons is predicted. On the continental land, areas with optimal conditions for searching for oil and gas accumulations in different geological conditions are planned. Priority areas for setting initial works are recommended.

Key words: gas, oil, hydrocarbons, depression, deflection, shelf, borehole.

Science and Education, 2017, No.4, pp. 50-59.