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BITUMENS IN THE COMPOSITION OF THE UPPER JURASSIC DEPOSITS OF WEST SIBERIA AND THEIR CONNECTION WITH THE HYDROTHERMAL PROCESSES

M. Iu. Zubkov

Western-Siberian Geological Center, Tyumen, Russia

Various examples of bitumen in the Upper Jurassic deposits of the West-Siberian oil and gas basin are considered. The connection of their formation with hydrothermal processes occurring in the deposits under consideration has been established. The main reasons for the S1 peak appearance on pyrograms of various rock types are listed. It has been established that at least in the high-temperature sections of the West-Siberian basin, rocks of the Bazhenov Formation and its analogues contain bitumen. It has been established that bitumens of the Upper Jurassic sediments belong to the class of thiobitumens. An approximate temperature limit has been experimentally established above which bitumens are formed in rocks containing organic matter. Reasons causing a regular change in intensities and the very presence or absence of various types of peaks S1, S2o and S2 on pyrograms are considered. A mechanism for the deposition of bitumen in the Upper Jurassic reservoir rocks is proposed.

Keywords: Upper Jurassic deposits, hydrothermal fluid, bitumen, pyrolysis, droplet chromatography.

DOI 10.20403/2078-0575-2019-1-9-24