定边油田樊学地区延9油层组油藏特征与成藏模式

Characteristics of Reservoir and Accumulation Model of 9th Member of Yan'an Formation in Fanxue Area,Dingbian Oilfield

为了厘清鄂尔多斯盆地定边油田樊学地区延9油藏的成藏期次,认识成藏主控因素并建立成藏模式,本文运用薄片显微鉴定、包裹体特征与均一温度、荧光光谱分析等测试分析手段,对延9油藏组的油藏特征、成藏期次及成藏主控影响因素进行了研究。研究结果表明,延9油藏主要为构造—岩性油藏,储层孔隙度平均值为15.6%。渗透率介于0.68~613.53 mD之间,平均值为74.36 mD,属中—高孔隙度、中—低渗透率储层。延9油层组在晚白垩世—早第三纪(102~45 Ma)发生了一期成藏,延9油藏是下伏延长组油藏在晚白垩世—早第三纪期间因构造抬升调整,运移至延9砂体后,油气在浮力作用下继续运移至局部构造高点岩性圈闭中聚集成藏。构造活动、河道砂体厚度和展布、局部构造对延9油气富集具有重要的控制作用。

Thin section observation, homogeneous temperature of inclusion and frequency spectrum analysis were conducted to analyze the oil accumulation period, controlling factors of oil accumulation and the migration and accumulation model of the sandstone reservoir of9 th member of Yan’an formation in Fanxue area of Dingbian oilfield, Ordos Basin. The main type of oil reservoir of 9 th member of Yan’an is structural-lithologic reservoir. The porosity of the reservoir ranges from 6.1% to 30.9 %, with average 15.6 %. The permeability ranges from 0.68 to 0.613 mD, with an average of 74.36 mD. The homogeneous temperature of inclusion indicate that the oil migration and accumulation in reservoirs of 9 th member of Yan’an during Late Cretaceous to Paleogene, the corresponding geological age is 102~45 Ma. The oils in reservoir of 9 th member are from the adjusted Yanchang reservoir because of tectonic movement, and migrated through sandstone carriers, fractures and accumulated in the structural-lithologic reservoir. The tectonic movement, thickness and distribution of sandstone and higher local structure are important controlling factors on oil accumulation.