鄂尔多斯盆地靖边油田大路沟区长2油藏成藏特征

综合利用烃源岩地球化学、薄片分析、常规物性、测井曲线、流体包裹体及试油等资料, 研究了鄂尔多斯盆地靖边油田大路沟区长2油藏油源条件、储层特征、成藏年代及油气富集规律. 结果表明: 大路沟区发育长7优质烃源岩, 黑色页岩有机碳平均为4.57%, 有机质类型为以生油为主的Ⅰ—Ⅱ₁型, 并已达到大量生油阶段, 可为长2油藏的形成提供物质基础. 长2油层组河道砂坝砂体储层物性较好, 面孔率平均高达11.4%, 储油能力强. 长2油藏类型为构造-岩性复合型, 具有油水界面; 矿物颗粒内流体包裹体均一温度揭示出油藏主要形成于早白垩世中晚期, 时间约为115 Ma; 长2油藏分布和富集主要受圈闭发育位置与规模、储盖层有效配置及储层物性的综合控制. 该研究可为靖边油田长2油藏的勘探部署提供地质依据.

ACCUMULATION CHARACTERISTICS OF CHANG-2 RESERVOIR IN DALUGOU AREA OF JINGBIAN OILFIELD,ORDOS BASIN

The oil source conditions, reservoir characteristics, accumulation age and oil-gas enrichment rule of Chang-2 reservoir in Dalugou area of Jingbian Oilfield, Ordos Basin, are studied based on the data of source rock geochemistry, thin section analysis, general physical properties, logging curves, fluid inclusions and oil test. The results show that the Chang-7 high-quality source rocks are developed in Dalugou area, with 4. 57% of average organic carbon content in black shale. The organic matter belongs to mainly oil-generating I—II₁ type, reaching the stage of massive oil generation, which can provide material basis for the formation of Chang-2 reservoir. The channel sandbar in Chang-2 oil layer formation has good reservoir physical property with the average apparent porosity as high as 11. 4% and strong oil storage capacity. The Chang-2 reservoir type is structure-lithology compound with oil-water interface. The homogenization temperature of fluid inclusions in mineral particles reveals that the reservoir was mainly formed in the middle and late Early Cretaceous (about 115 Ma). The distribution and enrichment of Chang-2 reservoir are mainly under the integrated control of location and scale of trap development, effective configuration of reservoir-cap rocks and reservoir physical properties. The study can provide geological basis for the exploration and deployment of Chang-2 reservoir in Jingbian Oilfield.