The Tectonic Environment,Typical Gas Pools and Exploration Direction of Coal type Gas Provinces in China
Coal type Gas of Mesozoic and Cenozoic TAO Ming xin XU Yong chang CHENG Jian fa SHEN Ping (State Key laboratory of Gas Geochemistry,Lanzhou Institute of Geology,Chinese Academy of Sciences,Lanzhou 730000)
The coal type gas resource of Mesozoic mainly concentrates on the North China where the Northwest area is the most favorable region, and the gas source rocks are almost Jurassic coal series.The Turpan Basin is a typical coal type gas basin where C 1/C 1-5 value of HongTai 2 gas pool is 0.887,and its δ 13 C 1-4 values and 40 Ar/ 36 Ar ratio are -39.1‰,-26.5‰,-25.4‰,-25.2‰ and 571,respectively.And these indicate that the Middle Jurassic series are self generated and self reservoired coal type gas pools,and the reversion of tectonic environment is the special structural condition for source rock to generate and concentrate coalbed gases. The coal type gas resource of Cenozoic mainly concentrates on the rift valleys of continental shelf along the seawest of the East China,and the Upper Tertiary coal series and their chief source rocks,The Ya 13 1 gas field located in the South of HaiNan Province is also a typical one that its δ 13 C 1,value varies from -39.9‰ to -35.5‰,δ 13 C 2 value varies from -26.8‰ to -24‰,and its gas belongs to pyrolysis genesis.The high temperature tectonic environment (thermal gradient of the Earth exceeds 4℃/100 m)is the favorable factor for the Tertiary to generate hydrocarbon,however,anticline and fault trap is the most helpful structural condition of concentration and reservation.
【CateGory Index】： P618.11