鄂尔多斯盆地西缘和南缘古生代前陆盆地及中央古隆起成因与油气分布

鄂尔多斯盆地位于华北板块西部,是我国大型叠加型含油气盆地之一。在对其进行的首轮油气勘探中发现了中生界大型油田,在二轮普查中对古生代的研究取得了突破和进展。上古生界广泛分布的海陆过渡相碎屑岩、中元古界及下古生界发育的海相碳酸盐岩都是优良的生烃源岩,加里东期风化壳是有利的天然气储集场所。盆地西缘和南缘是在元古界秦祁贺三叉裂谷基础上发育的早元古代被动大陆边缘,并发展成为主动大陆边缘,在中奥陶世(O₂)—中石炭世(C₂2)秦祁海槽向东、向北方向俯冲碰撞,并形成了古生代前陆盆地,其前隆部分构成“L形”的中央古隆起。古生界前陆盆地的西缘逆冲带、南缘逆冲带和中央古隆起是古生界有利的油气勘探区

The genesis and hydrocarbon distribution of western and southern margins of Paleozoic foreland basin and central paleouplift in Ordos Basin

The Ordos Basin,one of the large composite and hydrocarbon_bearing basins,is located in the western part of North China plate.The large_scale oilfield of the Mesozoic has been found in the first cycle of exploration.In the second cycle,the study on the Paleozoic has achieved breakthrough and high_speed progress.The transitional environmental detrital rocks broadly distributed in the Late Paleozoic and the marine environmental carbonaceous halite developed in the Early Paleozoic and Middle Proterozoic are all the excellent hydrocarbon source rocks.The weathering crust of the Caledonian has the advantage of the natural gas accumulation.The western and southern margins of the Ordos Basin are the passive continental margins developed on the basement of the Proterozoic three_fork rift of Qin(ling)_Qi(lian)_He(lan) area and gradually developed as the active continental margins.From the Middle Ordovician (O 2) to the Middle Carboniferous (C 2),Qin(lin)_Qi(lian) ocean troughs were subducted and collided to the directions of east and north.Therefore,the Paleozoic foreland basins were formed,and its forebulges were changed into "L_shape" of central paleouplift in the plane.The western margin thrust belts,the southern margin thrust belts and the central paleouplift are all the favorable areas for oil and gas exploration of the Paleozoic.