Laboratory Modeling of Organic Matter Maturation in Bazhenov Source Rocks: Hydrocarbons Composition Variation in Time

Summary The abstract represents the results of pyrolysis and GC-MS investigations of step-by-step laboratory modeling of organic matter maturation in Bazhenov formation rocks. Two rock samples with immature kerogen were heated in autoclaves under 300°C and 30 MPa, with sampling of liquid products and rock pieces each 12 h. The results have shown that pyrolysis parameters TOC, S2 and HI decreased exponentially, simulating all steps of kerogen maturation, and hydrogen index reached 70 mg HC/g TOC in 7–8 days, representing the kerogen achieve end of oil window. N-alkanes were generated only during first 5–8 days depending on the sample, with predomination of n-alkanes with odd number of carbon atoms after 3–5 days. Biomarker parameters that characterize both maturity and deposition conditions change during kerogen cracking, which means kerogen not only become more mature, but have complicated structure and consists of algae and marine organisms. Patterns for hydrocarbons generation depending on different nature of kerogen were determined. Further studies on larger amount of Bazhenov samples are necessary, but obtained results allow to investigate kinetics of kerogen cracking and specified compounds production.