鄂尔多斯盆地彭阳地区侏罗系延安组油气成藏主控因素分析

分析了鄂尔多斯盆地彭阳地区侏罗系延安组油藏成藏特征,并探讨了烃源岩、沉积、储层、构造等成藏主控因素,为寻找该区油气勘探有利区提供参考。结果表明:彭阳地区侏罗系延安组油藏类型为岩性圈闭和构造圈闭,岩性圈闭油藏主要受沉积因素控制,构造圈闭油藏主要受断层圈闭和构造因素控制;延安组烃源岩主要为炭质泥岩及暗色泥岩,有机质丰度较高,侏罗系成藏具有良好的油源条件;侏罗系延9、延8及延7沉积期间发育的三角洲平原分流河道砂体是重要的储集层,河流边滩微相砂体及河道心滩砂体是最有利的储集砂体;侏罗系延安组储层物性越好,含油性越好;侏罗系延安组构造复杂多样,断层和穹窿及小型鼻状隆起等微构造十分发育。综合分析认为,主砂体与有利构造叠合部位形成的构造圈闭和岩性圈闭是最有利的油气聚集区;侏罗系石油勘探重点应在穹窿、鼻隆等构造高点部位与主河道叠合区。

Main Factors Influencing Oil Reservoir in Jurassic Yan'an Formation in Pengyang Area,Ordos Basin

The characteristics of oil reservoir in Jurassic Yan'an Formation in Pengyang Area, Ordos Basin were analyzed, and the factors influencing oil reservoir, which were hydrocarbon source rock, sedimentation, reservoir and structure, were discussed in order to search the payable oil development area. The results showed that the types of oil reservoirin Jurassic Yan'an Formation in Pengyang Area were lithologic and structural traps, oil reservoir of lithologic trap was influenced by sedimentation, and that of structural trap was influenced by fault trap and structure; delta plain distributary channel sand reservoir, which developed in Jurassic Yan-9, Yan-8 and Yan-7 Formations, was an important reservoir, and marginal bank and river island micro sands were optimum reservoir; the more physical property of reservoir in Jurassic Yan'an Formation, the better petroliferous property; structure was complicated, micro structures(such as fault, fornix, small nose uplift, etc.)fully developed in Jurassic Yan'an Formation. In general, lithologic and structural traps, which developed in superposition part of main sand and favorable structure, were the most favorable oil gas accumulation area; the superposition part of high point of structure(such as fornix, nose uplift, etc)and main watercourse could be important for oil prospecting in Jurassic.