The marine mniddle and lower petroliferous associations of Tarim,Sichuan,and Ordos basins in West China are the key areas for oil and gas exploration around the country.To disclose the characteristics of oil and gas distribution is crucial for the on-going exploratory discoveries and the exploration efficiency promotion.Based upon the new discoveries and the new advances in petroleum exploration during the recent years,the paper applied the comparative method to discuss the tectonic controls upon oil and gas occurrence.It is shown that the marine basins,such as Tarim,Sichuan,and Ordos basins,are located in the composite area of the Paleo-Asia Ocean and the Tethys Ocean tectonic domains,and are multi-cycle superimposed basins developed upon the pre-Cambrian crystalline basement.They underwent three extension-compression cycles during the Sinian to Middle Devonian,(Late Devonian-)Middle Carboniferous to Triassic,and Jurassic to Quaternary periods,respectively.Each cycle develops the independent hydrocarbon source-reservoir-cap rock assemblages,characterizing by the excellent source rocks occurred in the differentially subsided areas during extension periods,and the large-scale spreading of the reservoir rocks and the trap associations during compression periods.The basin structures are featured of stratified vertically and faulted blocks horizontally.The bascment sub-division played a role in the formation of the above sedimentary proto-type basins.It is demonstrated that the superimposing styles among the proto-type basins controlled the hydrocarbon accumulation strata and accordingly the rich areas and plays.The oil and gas enrichment areas in the basins are formed due to the two constructive tectonic movements such as the Middle Caledonian and the Indo-China,and the two adjustment movements such as the Late Yanshanian (Late Jurassic to Early Cretaceous Period) and the Late Himalayan (Pliocene to Quaternary).It is common for pool-formation in the neo-tectonic period.The marine superimposed basins are entitled of a series of petroliferous beds and intervals,especially of the superimposed boundaries among the proto-type basins proved to be an important area for oil and gas accumulation;and many oil and gas accumulation zones or areas occurring along the uplift belt,the fault zone,the platform marginal zone as well as the litho-facies variation zones.It is concluded that the middle and lower association of the superimposed basins is favorable for the next on-going breakthrough in petroleum exploration.%中国西部塔里木、四川、鄂尔多斯等海相盆地的中、下组合是我国油气勘探的重点领域,深化研究油气分布规律是优化勘探部署、提高勘探效益与持续获得勘探发现的关键.本文从盆地地质结构控制油气分布的学术思路出发,立足于近年来的勘探新进展、新发现,应用比较分析方法,揭示油气分布的构造控制规律.研究表明,塔里木、四川、鄂尔多斯等海相盆地位于古亚洲洋构造域、特提斯构造域的复合作用区,是在前寒武纪克拉通基础上发展起来的多旋回叠合盆地;它们经历了Z-D2、(D3-)C2-T、J-Q等三个伸展-聚敛旋回的演化;每一伸展-聚敛旋回发育了独立的生-储-盖组合,伸展期因差异沉降发育好的烃源岩,聚敛期发育大规模展布的储集体与圈闭组合;盆地的基底分区对后期原型盆地的发育和沉积盖层的分布具有明显的制约作用,盆地多旋回叠合,形成了“垂向分层、横向分块”的地质结构,叠合结构样式控制了油气聚集层系与富集区带,普遍存在加里东中期与印支期等两期原生油气成藏期,及燕山中期(J3-K1)与喜马拉雅晚期(N2-Q)等两期油气调整成藏期,新构造运动期油气成藏较为普遍.海相叠合盆地含油气层系多,原型盆地的叠合界面常是重要的油气富集部位,隆起带、断裂带、台缘带(或岩相带)是重要的油气富集区(带),叠合盆地的中下部组合是下一步油气勘探持续突破的有利方向.
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