Reservoir Description Of An Ding Area In Zichang Oil Field

Anding block of Zichang oilfield is located in Liuniwan of Anding town—Sigou of Siwan in Yanan, whose structure is a west dipping monoclinal structure in the Shanbei slope of eastern Eerduos Basin. Major reservoir is the Chang-6oil layer of Yanchang Formation of the Late Triassic. The proved oil area is30.36km2and the proved reserves is1272.6×104t. The block reported its proved oil reserves in2006and was placed full development. This study used CorelDraw, Geomap, Geolog, Petrel, and guided by the Sequence stratigraphy, seismic exploration, geophysics, computer technology Theory, and combined with core, logging, master log, DST, production data, etc. The Chang6oil layer is divided into4sand sets and9subzones from bottom to top by well seismic calibration. By methods of well logging sedimentary facies and core facies analysis, predicting cross-well sandbody and studying characters of plane and profile distribution of sedimentary facies, the main facies of the subject reservoir are delta-front facies and the main oil and gas reservoir is the sub-channel branch sand body. Fine logging interpretation model and reservoir parameters cut-off are built by studying four property relationships, the gas and oil porosity cutoff is19%, the permeability cutoff is0.3mD, the oil saturation cutoff is40%. By analysising the reservoir heterogeneity, the reservoir heterogeneity is very strong in the Chang6reservoir with extra low porosity and permeability. Based on reservoir fluid property analysis, the Chang6oil layer is a lithologic reservoir with elastic drive and depleted drive. Stucture modeling is built under controlling of the seismic interpretat, faults modeling and well tops by intrapolated and extrapolated methods. Facies modeling is built using Sequential Indicator Simulation method with seismic attribute trend. Porosity modeling is based on the facies model using SGS method. Permeability modeling is based on the porosity model using collocated-cokriging.3D geological modeling is built, Based on above study results, three types favourable-region are forecasted. Above are provided with reliable base geological data for development program study of Oilfield.