Three-dimensional basin modeling study on Zhangjiatan shale gas area in Ordos Basin

Abstract

Three-dimensional basin modeling which combines geochemical and reservoir parameters can make a very good simulation of the heterogeneity of shale gas distribution and the process of its accumulation. Geochemical analysis implies that Zhangjiatan shale in Ordos Basin has a high TOC content with a moderate organic maturity. Production data also demonstrate the shale has a great potential of gas generation. Solid geological background materials, geochemical data and reservoir parameters were applied in the simulation of the geological evolution history, geo-thermal history and hydrocarbon generation and expulsion history of the shale. The distribution of shale gas was predicted by the three-dimensional basin modeling, and gas constitution, adsorb to free gas ratio, resource and reserve of the shale gas were also calculated. It was speculated that the organic conversion of the shale is about 20% and about 80% of the hydrocarbon that had been generated was expelled out of the source rock. Basin modeling result manifests that most of the shale gas is distributed to the west of Fuxian in adsorbed phase with a geological resource of 0. 15×1012m3. Calibration on porosity, maturity and gas content verified that the basin modeling is solid. It was concluded that the three-dimensional basin modeling is a reliable way in shale gas resource evaluation especially in well researched areas in China.