oa HYDROCARBON PROPERTIES OF THE BAZHENOV FORMATION SOURCE ROCKS WITH DIFFERENT MATURITY

Bazhenov formation source rocks from wells with different maturity of organic matter were investigated by sequential extraction. Hydrocarbons extracted with hexane from open pores and with chloroform from blocked pores were investigated by FID-GC and GC-MS methods. It was found that hydrocarbons composition in open and blocked pores depends not only on maturity, but also on lithological composition of rocks and migration processes. In one well not only maturation, but also sedimentary condition biomarker parameters may vary through the depth of section. Reservoirs are filled with migrated hydrocarbons, that are of higher maturity and contain higher amount of n-alkanes with shorter chains in hexane extracts. Hydrocarbons formed in continental conditions were also found in the rocks at the bottom of Bazhenov formation, formed in marine conditions, which means there was another source rock deeper than Bazhenov formation. Concentration of silica, carbonates and pyrite affect the processes of hydrocarbons generation and influence some biomarker parameters values. That is lithological and reservoir properties of the Bazhenov source rocks as well as maturity of organic matter should be analyzed for investigation of oil and gas generation and migration processes.