Organic Geochemistry and Source Rock Potential of the Bazhenov Black Shales form the West Siberian Basin, Russia

Abstract

Summary The West Siberian Basin (WSB) constitutes the largest petroleum province in Russia. The oil accumulations in the WSB are mainly sourced by the Upper Jurassic Bazhenov Formation (BF). This study aims to provide information on the geochemical and petrographic characteristics of a representative sample set of the siliceous BF black shales from the Southwest Ob region in the southwestern WSB. On 39 samples, comprehensive analyses and observations were performed, including total organic, inorganic carbon (TOC and TIC) and total sulfur content (TS) measurement, Rock-Eval pyrolysis, organic petrography and molecular geochemistry. The samples show excellent source rock potential and oil-prone source rock characteristics, mainly containing organic material that can be assigned to Type II kerogen. The black shales were deposited in a marine depositional environment with periodically anoxic conditions. The evaluation of maturity sensitive properties imply that the 39 samples are affected by varying degrees of thermal maturity covering the catagenesis stage from the onset to the end of the oil window.