Basin dynamical features of coal-related gas assemblage in Jiyang Depression

Jiyang area is of the material base and the dynamic background for the assemblage of the coal-related gas.That is,the Permo-Carboniferous strata are preserved well in some fault-blocks of Mesozoic-Cenozoic era in Jiyang Depression.The rock series producing the hydrocarbon and the gas have developed which are characterized by the coal-bearing strata.The upper strata of Permo-Carboniferous(for example,broadly and stably distributed upper Shihezi Formation sandstones) are of good condition for reservoir development.The regional caps produced the confining condition for the coal-related gas enriching into the deposits.Therefore,the Permo-Carboniferous strata possessing the good assemblage of the source,the reservoir and the cap are of the most important geological condition for the coal-related gas enriching into the deposits in Jiyang Depression.