Catagenesis of organic matter at the top and base of the Jurassic complex in the West Siberian megabasin

Abstract

Thermal maturation for the top and base of the Jurassic in the West Siberian megabasin was modeled on the basis of the vitrinite reflectance (Rvt0) data using mathematical modeling and computer simulations. The values of thermal maturation are found to vary within substages PC3–MC32 for the top (or being equivalent to PC3-MC12 on the periphery and southern part of the basin, or to MC2-MC32 in the north) and PC3-AC3 for the base of the Jurassic (or being equivalent to PC3-MC2 on the periphery and southern part of the basin or MC31-AC3 in the north). Thermal maturity levels of the Jurassic in West Siberia are controlled by depths of burial and peak temperatures which the source rocks were subjected to during this period. The situation is further complicated by high heat flows superimposed on the regional background, which are observed in deep fault zones and in the proximity of numerous igneous bodies.

Alginite-Rich Layers in the Bazhenov Deposits of Western Siberia

“…The TOC variations are usually accompanied by considerable variations of the hydrogen index (HI), chemical and isotope composition, and level of organic matter thermal maturation [1][2][3][4]. These variations reflect the changes in sedimentation conditions, including the rate of sedimentation, diversity of marine biota and bioproductivity, redox conditions, and others [5][6][7]. In the case of the Bazhenov Formation, the effect of these factors on the hydrocarbon formation process and hydrocarbon productivity is not yet fully understood and requires additional studies, based on detailed analysis of OM composition, properties, and sources for different areas.…”

Strike-slip deformations in the West Siberian Basin and their impact on exploration and development of oil and gas reservoirs

“…To predict the presence of SSFS in the rest of the West Siberian basin, the structure map of the Albian-Cenomanian (Kontorovich and Nesterov 2000;Fig. 10) has been used.…”

Thermal maturity of uppermost Middle Jurassic sediments in the West Siberian basin

“…However, most of publications are restricted to specific areas of the basin. Alexei Kontorovich and his group were the first to synthesize the available data on catagenesis on the regional-scale in their early works (Kontorovich et al, 1967a and continued the research till recently (Kontorovich et al, 2009). They have successfully predicted the maturation history of Jurassic reservoirs in Arctic and Subarctic West Siberia.…”

“…More than 1500 measurements of vitrinite reflectance (R vt o ), along with mathematical modeling and computing, have been used to map the thermal maturity (catagenesis) of uppermost Middle Jurassic sediments in the West Siberian basin. The map was compiled with reference to the cited publications, following the method reported by Kontorovich et al (2009). The machine-aided contouring results for some areas were corrected and smoothed.…”