Laboratory Modeling of the Bazhenov Formation Organic Matter Transformation in a Semi-Open System: A Comparison of Oil Generation Kinetics in Two Samples with Type II Kerogen

In this study, Kerogen conversion and oil production laboratory modeling results in Bazhenov formation source rock samples (Western Siberia, Russia) are presented. Two samples from one well with a similar composition and immature type II kerogen, which were accumulated in the same deep-sea conditions, were used for this investigation. Hydrous pyrolysis was performed under 300 °C, with liquid products and a sample portion collected every 12 h to study kerogen parameters via pyrolysis and the synthetic-oil composition via GC–MS. The transformation of pyrolytic parameters was similar to the natural trend previously determined for Bazhenov source rocks with different maturities. The synthetic oils’ normal alkane composition and biomarker parameters transformed with time. Sedimentary conditions and lithology biomarker parameters presumed to be constant (Pr/Ph, Ph/C18, H29/H30, and DBT/Phen) changed depending on the heating duration. The oil maturation increased slightly. Differences between the samples were detected in hydrocarbon generation endurance (5 and 8 days), n-alkane composition, and C27/C29 and DBT/Phen. A hypothesis about the influence of kerogen variability and mineral matrix on oil production was made. This paper provides the basis for more detailed and accurate investigation of the factors affecting kerogen cracking and hydrocarbon formation.