DEGASIFICATION METHODS AND APPLICATION OF HIGH QUALITY MARINE SOURCE ROCKS IN SOUTH CHINA

Degasification methods of adsorbed gas and acid decomposed gas in marine facies source rocks in South China are studied in this paper.GC and isotopes analyses of gas compositions are also done.The maximum relative deviation of composition contents is less than 10%,and the maximum absolute deviation of carbon isotopes is less than 1‰.Applications of the methods are studied.Coal samples are not fit for acid decomposed gas analyses.Methane isotopes of adsorbed gas generally will not be influenced by organic matter or carbonate contents.But for methane isotopes of acid decomposed gas,things are different.Acid decomposed gas is favorable for gas-source correlation.Evolution model studies of carbon isotopes of adsorbed gas and acid decomposed gas from marine facies Permian source rocks in South China are done,indicating that,as evolution degree increases,carbon isotopes of adsorbed gas and acid decomposed gas become heavier until over-mature stage.