Evolution of the CBM reservoir-forming dynamic system with mixed secondary biogenic and thermogenic gases in the Huainan
The secondary biogenic gas is an important original type of the coalbed methane (CBM) in China. Based on the analyses of sedimentary and burial history of the Permian coal-bearing strata, combined with thermal history and gas generation process of coals, the CBM reservoirforming dynamic system with mixed secondary biogenic and thermogenic gases in the Huainan Coalfield is subdivided into four evolutionary stages as follows: (i) shallowly-buried peat and early biogenic gas stage; (ii) deeply buried coal seams and thermogenic gas stage; (iii) exhumation of coal-bearing strata and adsorbed gas lost stage; and (iv)re-buried coal-bearing strata and secondary biogenic gas supplement stage. The Huainan CBM reservoir-forming model has the features of the basin-centered gas accumulation. The evolution of the reservoir-forming dynamic system proves that the thermogenic gas is not the main gas source for the Huainan CBM reservoir. Only the secondary biogenic gases as an additional source replenish into the coal bed after basin-uplift, erosional unroofing and subsequent scattering of thermogenic gases. Then this kind of mixed CBM reservoirs can be formed under suitable conditions.
作 者： ZHANG Hong CUI Yongjun TAO Mingxin PENG Gelin JIN Xianglan LI Guihong 作者单位： ZHANG Hong,CUI Yongjun,JIN Xianglan,LI Guihong(Institute of Geology, Xi'an Branch, China Coal Research Institute, Xi'an 710054, China)TAO Mingxin(Key Laboratory of Gas Geochemistry, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 73000, China)
PENG Gelin(Changsha Institute of Geotectonics, Chinese Academy of Sciences, Changsha 410013, China)
刊 名： 科学通报（英文版） SCI 英文刊名： CHINESE SCIENCE BULLETIN 年，卷(期)： 2005 50(z1) 分类号： Q1 关键词： coalbed methane (CBM) secondary biogenic gas thermogenic gas evolution reservoir-forming dynamic system the Huainan Coalfield