Выпуск: 12 , Том: 66 , Год издания: 2025

The article presents the results of detailed organic geochemistry studies being part of a comprehensive (lithological, geochemical, petrophysical) study of the Bazhenov Formation in the Tomsk Region using the IPGG SBRAS methodology for organic matter-rich source rock. As the thermal maturity increases from PK3 to MK2, the content of 'free micro oil' in source rock's pore spaces has been observed to increase. In the same time, there are modifications to the composition of bitumoids (chloroform source rock extracts) from open and closed pores at both the group and molecular levels. Even 'immature' organic matter has been establish to show a difference in bitumoids composition from open and closed pores, which increases as it enters the main phase of oil formation.