Nanpu Sag The Second Member Of Dongyingzu Formation Mudstone Caprock Sealing Capacity Comprehensive Evaluation

In order to study the sealing capability of Nanpu Sag Second member of Dongying Formation mudstone and its controls on oil and gas reservoirs, by using the present foundation drilling, well logging, seismic data and analytical testing has on the Nanpu Sag of Second member of Dongying Formation mudstone caprock macroscopic development and distribution of microscopic sealing ability was studied, combined residual pressure reservoir characteristics of mudstone caprock under Second member of Dongying Formation, natural gas percolation through mudstone caprock migration pressure gradient remaining relatively under pressure size, Second member of Dongying Formation mudstone caprock sealing gas ability of a comprehensive set of evaluation and analysis of the role of control function to Second member of Dongying Formation mudstone caprock for gas accumulation and distribution, the specific results obtained and cognition. Nanpu Sag Second member of Dongying Formation mudstone caprock macro area distribution widely, its thickness is large, the overall trend of the performance of shale thickness southwest to northeast direction by gradually thinning; its high-value areas are mainly distributed in the west of the depression, the maximum value of thickness is 430 m, within the overall cap thickness in the range of 200 m or more. Second member of Dongying Formation mudstone the overall range of mud content is between 0.4 to 1.0. High mud content value area is in the northwest and southeast which it distributes bandingly. Second member of Dongying Formation Caprock displacement pressure characteristics, displacement pressure mainly in high value area of Nanpu Sag, southwest, the maximum of pressure is 7.8MPa. Second member of Dongying Formation mudstone caprock under corresponding reservoir gas reservoirs residual pressure is 0.04 ~ 11.92 MPa, averaging residual pressure is 2.66 MPa, nowadays mudstone caprock displacement pressure is greater than the residual pressure gas reservoirs, gas reservoirs sealing ability to be effective. Second member of Dongying Formation sealing ability of mudstone caprock class is differences more obviously. In the east and south-west and north-west region has good validity cap is distributed bandingly. All of the natural gas under Second member of Dongying Formation mudstone caprock distribution level is evaluated as good and better areas. Control function of gas cap embodying both in space and time capacity. Space capacity, Nanpu Sag Second member of Dongying Formation large macro mudstone caprock thickness, are distributed throughout the region mudstone caprock, and fracture damage to the overall cap on small space, oil and gas cap is sealed effectively. Time capacity, Second member of Dongying Formation mudstone caprock ability to form a closed oil and gas during the period before the beginning of a large number of Minghuazhen Formation deposition in the late time in third member of Shahejie Formation hedrocarbon source rocks, and the amount of the expulsion period has not reached maximum exhaust period, therefore, mudstone caprock for gas in the reservoir into the respective sealing ability over time to be effective. In summary, Second ember of Dongying Formation mudstone caprock in Nanpu Sag most areas having a closed gas reservoir capacity. For natural gas migration and accumulation and preservation conditions play a crucial role.