Distribution Characteristics of Natural Gas in Eastern China

There are various genetic types of natural gas in eastern China,which are mainly biogenic hydrocarbon gas,abiogenic hydrocarbon gas and inorganic CO2.Large biogenic hydrocarbon gas fields discovered at present are mainly distributed in the Ying-Qiong basin(Ya 13-1 gas field,Ledong 22-1 gas field,Dongfang 1-1 gas field),Pearl River Mouth basin(Panyu30-1),Eastern China Sea basin(Chunxiao gas field) and Taixi basin(Tiezhanshan gas field) in the Continental Shelf,and ethane carbon isotope is heavier than-28‰,which shows that the gas is coal-derived.Large abiogenic hydrocarbon gas fields are distributed in the deep part of Songliao basin(Xingcheng gas field,etc),and the natural gas is characterized by heavy methane carbon isotope(δ13C1-30‰),negative carbon isotope series and R/Ra0.5.The distribution of CO2 gas fields(gas reservoirs) is wide from the Songliao basin in north to the Ying-Qiong basin in south,and total 35 CO2 gas fields(gas reservoirs) have been discovered in these areas with CO2 content more than 60% and δ13CCO2 heavier than-28‰.