Scientific Basis of Hydrocarbons Generation and Accumulation in Bazhenov Formation Rocks: Comparison of Rock Samples Investigation and Laboratory Modeling Results

Summary Complex investigation of Bazhenov source rocks was made to study patterns of hydrocarbons generation and accumulation. Sequent soxhlet extraction and heating in autoclaves with water were used to determine amount of existing and generated hydrocarbons in the rocks. Composition of hydrocarbons was investigated using GC-MS. It was shown that kerogen maturity plays role in the accumulation of generated compounds, and asphaltenes might block part of pore space. Rock composition affects process of hydrocarbons generation. Espetially amount of silica and carbonates. In the middle-end of oil window some oil migrates higher through the section, some is captured with asphaltenes, and hydrocarbons from lower formations can move inside Bazhenov formation. Experiments that model hydrocarbons generation show good agreement with natural processes. It was found that the highest amount of newly formed compounds accumulate in the rocks, and at least half of hydrocarbons is blocked with asphaltenes. Kerogen nature highly affect the process of n-alkanes, polyaromatic compounds and other hydrocarbons generatinon. The method designed in this work allows investigating the nature of kerogen, model processes of hydrocarbons generation and accumulation, and increase accuracy of basin modeling and oil fields search.