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根据气体组分、甲烷同系物碳同位素及轻烃参数,确定济阳坳陷孤北潜山带煤成气源主要为石炭—二叠系煤系烃源岩,中生界煤系烃源岩也具有一定的贡献,煤成气主要分布于第二排山、第三排山北部远离孤北断层地区及第四排山。在煤成气源确认的基础上,通过储集层流体包裹体均一温度及生烃动力学分析,结合烃源岩的生烃—埋藏史,认为该区石炭—二叠系煤系烃源岩经历了4次生烃过程,燕山期和喜马拉雅期是主要生烃期,中生界煤系烃源岩生烃期主要为喜马拉雅后期。该区煤成气藏可能有2种成因,一是源自石炭—二叠系煤系烃源岩的原生气藏在喜马拉雅期被破坏后再次聚集而成;二是喜马拉雅期埋藏较深的石炭—二叠系及中生界煤系烃源岩再次生烃形成,其中第二种成因的煤成气是今后孤北潜山带天然气勘探的重点。
According to the gas composition, carbon isotopes of methane homologues and light hydrocarbon parameters, it is determined that the coal-formed gas source of the Gubei buried-hill belt in the Jiyang Depression is mainly composed of Carboniferous Permian coal series source rocks, Mesozoic coal measures source rocks Also has some contribution, coal gas is mainly distributed in the second row of mountains, north of the third row away from the Gubei fault area and the fourth row of mountains. Based on the confirmation of coal gas source, based on the homogenization temperature and hydrocarbon generation kinetics of fluid inclusions in the reservoir and the hydrocarbon generation-burial history of source rocks, it is considered that the Carboniferous-Permian coal measure source rocks After four hydrocarbon generation processes, the Yanshanian and Himalayan periods are the major hydrocarbon generation periods. The hydrocarbon generation period of the Mesozoic coal measures is mainly the late Himalayan. There are two possible causes for the coal gas pool in this area: first, the original gas pools derived from the Permo-Carboniferous coal-measure source rocks are re-aggregated after being destroyed in the Himalayan period; secondly, the deep-buried carboniferous rocks in the Himalayan period - Permian and Mesozoic coal-bearing source rocks are re-generated, of which the second genesis of coal-formed gas is the focus of future natural gas exploration in the Gubei buried-hill.