【摘要】 以往鄂尔多斯盆地中生界油气勘探主要强调在烃源岩范围之内寻找主砂带,很少注意构造对油藏的控制作用,但近年来,在鄂尔多斯盆地内部却发现了不少受低幅度隆起构造控制的油气藏。利用最新地震勘探与钻井资料,在大量野外露头调查、钻井岩心观察及地震剖面解释的基础上,对鄂尔多斯盆地中生界低幅度构造空间分布、形成机制及其与油气成藏的关系进行了深入分析。研究结果表明:(1)鄂尔多斯盆地天环坳陷东、西斜坡均存在大量有规律分布的低幅度隆起构造,其中延长组内沿近东西向、成排展布的大型低幅度鼻状隆起构造主要受基底古突起控制,而延长组与延安组内的局部隆起构造主要受断层相关褶皱、差异压实及复合成因等多重作用控制;(2)低幅度构造对天环坳陷东、西斜坡中生界油气成藏均有影响,其中大型低幅度鼻状隆起构造为油气大面积聚集提供了构造背景,因而其附近的局部隆起构造及非构造圈闭均是油气聚集成藏的有利部位。更多还原

【Abstract】 The oil and gas exploration of Ordos Basin in Mesozoic was mainly in the range of hydrocarbon source rocks for the main sandy belt,and little attention was paid to the control of the construct reservoirs in the past. But in recent years,within the Ordos Basin,it was found that a considerable number of oil and gas reservoirs were controlled by the low amplitude uplifted structure. In this paper,on the basis of the latest seismic exploration and drilling data,outcrop survey,observation of drilling cores and seismic profiles interpreted,we conduct in-depth analysis on the distribution of low amplitude structural space,formation mechanism and hydrocarbon accumulation relationship in Mesozoic of the Ordos Basin. The results show that: (1) In the east and west slopes of Tianhuan Depression,Ordos Basin,there are a large number of low-amplitude uplift structures with regular distribution,in which the large-scale distribution of low amplitude nose-shaped uplift structure nearly east-west along the rows is mainly controlled by paleo-protuberance in Yanchang Formation,and the local uplift structures of Yanchang and Yan’an formations are mainly controlled by the fault-related fold,differential compaction and composite geneses; (2) The low amplitude structures affects both east and west slopes of the Mesozoic oil and gas accumulation in the Tianhuan Depression,in which large low-amplitude nose-shaped uplift structure provides a large area of the oil and gas gathering tectonic setting,and near the locals,the uplift structure and non-structural traps are favorable parts of the oil and gas accumulation. The article also pointed out that seismic exploration and basic geological research should be vigorously strengthened.更多还原