Прогноз нефтегазоперспективных объектов в бассейне реки Виви (Сибирская платформа) по комплексу геолого-гидрогеохимических методов

Abstract

Large forecast resources and hydrocarbon reserves are concentrated in the Western part of the Siberian platform (Lena-Tunguska oil and gas province). But most of the explored resources of oil and gas are located in the Baikitskaya and Katanga anteclises. The understudied by geological and geophysical methods Kureya syneclise is located to the north of the territories of the Baikitskaya and Katanga oil and gas areas. The forecast and search for oil and gas in the vast poorly investigated areas by the advanced geochemical methods in combination with traditional geological and geophysical ones remain a relevant task of exploration. The oil and gas potential is estimated using a complex of geological and hydrogeochemical methods. These are the methods of tectonic forecast of buried uplifts and estimation of their oil and gas potential by the advanced hydrogasgeochemical methods (geochemical exploration methods designed for detecting the presence of hydrocarbons in surface waters and bottom layers). The buried uplifts located on the territory of the Central part of the Kureya syneclise are considered as potential hydrocarbon traps that accumulate oil and gas coming from the Riphean and Paleozoic sediments. The analysis of the hydrogasgeochemical samples taken above the buried uplifts shows that there is a latent discharge of mainly calcium chloride (sodium-calcium) underground brines in the basin of the Vivi river. The centers and discharge zones of fluids are associated with faults. The following oil and gas exploration indicators have been found in the composition of natural water and gas samples: water-soluble aromatic hydrocarbons, heavy hydrocarbons, which may indicate possible hydrocarbon saturation. The results obtained are consistent with the known ideas about the wide development of the ascending discharge of highly metamorphosed calcium chloride brines in the central part of the Tunguska artesian basin. Discharge at the bottom of rivers is the shortest and easiest way out of deep waters, therefore the beds of large rivers are considered drains for the deep waters coming from below. Especially intense flow is observed along the large rivers Lower and Podkamennaya Tunguska, Taimur, Tutonchan, Kochechum, Eika, etc. Fault zones almost always control surface anomalies, which can indicate the presence of oil and gas hydrocarbon accumulations in the sedimentary cover.