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.