鄂尔多斯盆地演武地区侏罗系延安组油藏成藏特征

鄂尔多斯盆地演武地区侏罗系延安组油藏规模小，成藏特征复杂，预测难度大。探讨演武地区侏罗系延安组油藏在地质历史时期是否存在二次运移与成藏，以及延安组油藏的主要成藏期次等，可为该地区油气勘探提供理论依据。通过颗粒荧光定量测试、流体包裹体分析等手段，对演武地区侏罗系延安组油藏的成藏特征进行研究。结果表明：延安组油藏存在古油水界面上升和油气逸散等地质事件，揭示出部分油藏在地质历史时期遭受过破坏并发生过油气二次运移。整体而言，演武地区侏罗系延安组油藏主要存在两期成藏，早期为早白垩世末的充注成藏，油气主要在延安组下部层位聚集成藏；晚期为晚白垩世以来构造抬升引起的油气二次运移成藏，油气在延安组上部层位聚集成藏。相比早期成藏，晚期的成藏区域更加远离长7生烃中心，两期成藏形成了演武地区侏罗系延安组油藏现今的分布格局。

Reservoir accumulation characteristics of Jurassic Yan'an Formation in Yanwu area,Ordos Basin

The reservoir of Jurassic Yan'an Formation is characterized by small scale, complex forming characteristics and it is difficult to predict in Yanwu area, Ordos Basin. In order to make clear the main accumulation time and whether there is a secondary migration accumulation in geological history period, and to provide theoretical basis for exploration, the reservoir accumulation characteristics of Jurassic in Yanwu area was studied through testing means such as quantitative grain fluorescence, fluid inclusions and so on. The results show that the ancient oil-water interface rise and hydrocarbon dissipation had ever happened in Yan'an Formation. Some of the reservoirs had suffered damage or the secondary hydrocarbon migration had happened in geological history period.The reservoir accumulation period of Yan'an Formation in Yanwu area can be mainly divided into two stages. The early accumulation stage was at the end of Early Cretaceous, and the oil accumulation was mainly in the lower layers of Yan'an Formation. The late accumulation stage resulted by tectonic uplift was since Upper Cretaceous, and the oil accumulation was in the upper layers of Yan'an Formation. The accumulation range of the late stage is more far away from Chang 7 hydrocarbon generation center than the early stage. The present reservoir distribution pattern ofYan'an Formation inYanwu area was formed jointly by the two accumulation stages.