鄂尔多斯盆地镇原油田侏罗系古地貌与油成藏关系分析

Relation between Jurassic paleogeomorphology and hydrocarbon accumulation in Zhenyuan Oilfield, Ordos Basin

利用钻井与测井资料,运用印模法对镇原油田侏罗系古地貌进行了恢复。在分析油藏分布与古地貌关系的基础上,系统总结了古地貌对油成藏的控制作用,进而建立了镇原油田侏罗系油成藏的主要模式。研究结果表明,镇原油田侏罗系主要发育河谷、支河谷、高地、斜坡和河间丘等5种古地貌单元。镇原油田侏罗系油藏受古地貌控制,主要分布于古地貌侵蚀高地周缘、斜坡前缘及坡嘴地带。古地貌控制油成藏的有利条件有:下切河谷内的厚层砂体是油运移的良好通道,河间丘和坡嘴是油优先聚集的部位,差异压实形成的低幅度构造是油运移的最终指向。镇原油田侏罗系油成藏模式有坡嘴式、河间丘式和古高地式等3种。

Based on drilling and logging data, copying method was used to recover the paleogeomorphology of Jurassic in Zhenyuan Oilfield. By analyzing the relation between reservoir distribution and paleogeomorphology, this paper defined the controlling effect of paleogeomorphology on hydrocarbon accumulation, and established the hydrocarbon accumulation model of Jurassic in Zhenyuan Oilfield. The result shows that there mainly developed 5 types of paleogeo- morphology units in Zhenyuan Oilfield, including valley, incised valley, highland, clinoform and mound. The Jurassic reservoir in Zhenyuan Oilfield is controlled by ancient landform, and mainly distributed in the erosion highland periphery of ancient landform and the front as well as the mouth of slopes. Ancient landform is favorable for reservoir formation： incised-valley controls the hydrocarbon migration channel, clinoform affects the types and distribution of reservoir sandstone, and differential compaction between highland controls the relatively high-points in structure. The models of Jurassic hydrocarbon accumulation are mainly slope-mouth, mound and ancient highland in Zhenyuan Oilfield.