鄂尔多斯盆地东部上古生界气藏成藏史

Gas accumulation history in upper palaeozoic,east of Erdos basin

应用生烃"时限"分析、储层流体包裹体以及储层自生伊利石K-Ar定年等成藏年代学方法,精细描述鄂尔多斯盆地东部上古生界不同含气组合气藏的成藏期次和成藏时间,实现了区内由传统的定性到定量或半定量研究的转变.研究表明:上古生界不同含气组合气藏从南到北、从下至上成藏时间依次变晚.中、下部含气组合主要两期充注,分别为200.0～175.0Ma和160.0～120.0Ma,后一期为天然气的主力充注期,成藏关键时刻为135.0Ma.上部含气组合属于次生气藏,为一期充注,主要成藏时间略晚,为150.0～97.5Ma,其与晚侏罗世—早白垩世构造运动密切相关.

Application of the time limit of hydrocarbon generation and expulsion analysis, reservoir fluid inclusions and K-At isotopic chronology of authigenic illite in reservoirs, etc, resulted in a fine description of different combinations of gas reservoir forming periods and accumulation time in the upper paleozoic, the eastern part of the Erdos basin, which has transformed the geochronological studies of petroleum accumulation from the conventional qualitative to quantitative or semi-quantitative means. Studies have shown that the accumulation time of different combinations of gas reservoir in the upper paleozoic in turn become too late from the south to the north and from the bottom to the top. There have been a two-stage charge in the bottom and middle combinations of gas reservoir, i.e. 200.0-175.0 Ma and 160.0-120.0 Ma; the latter period is important for the charge of natural gas and the critical time is 135.0 Ma. The upper combination gas reservoir is secondary gas reservoir because, with only one charge, the main accumulation time is slightly late, i.e. 150.0,-97.5 Ma. Its late Jurassic-early cretaceous tectonic movements are closely related.