Abstract:

With pyrolysis experiment, we extracted and analyzed the soluble organic matter  from original samples of hydrocarbon source rock of Jurassic coal measures in Zh ungeer basin and residual of different temperature, treated residual kerogen, me asured R_o and TOC, and gave chromatograph and mass spectrograph test to so me sample series. The results indicate that there is some geological and geoch emical difference of hydrocarbon source rock of coal measures at different therm al evolution stage, natural gas generated at low evolution stage and thermal deg radation stage is the result of different thermodynamic conditions and chemical  reaction of mother matter of gas generation. At low evolution stage, the vitrin ite reflectance of source rock does not increase much, usually R_o<0.7%.The analytical results of soluble organic matter of original samples and residue  in pyrolysis experiment indicate that hydrocarbon gas is mainly from releasing  of radicals of original soluble organic matter and thermal degradation of margin al hydrocarbon (polar component) of large-molecule bitumen and kerogen. At t hermal degradation-thermal cracking stage, the temperature of hydrocarbon sourc e rock increases following the increase of buried depth, and thermal evolution r elatively accelerates, the vitrinite reflectance increases from 0.55%~0.70% to 1.40%~1.70% quickly, at the same time, the thermodynamic effect is big enough  to destroy the constitutional hydrocarbon of kerogen to generate oil and gas, it is the time of kerogen to release a lot of hydrocarbon Geochemical parameter s at this stage show properties of thermal degraded constitutional hydrocarbon of kerogen.

Key words: Hydrocarbon source rock of coal measures, Evolution of pyrolysis, Geochemistry