Petroleum geological conditions and exploration potential of the Permian Qixia Formation in the middle segment of Western Depression, Sichuan Basin

Abstract

In recent years, great breakthroughs have been achieved for the exploration in the Permian Qixia Formation of the Shuangyushi structure in the north and the Pingluoba structure in the south of the Western Depression of the Sichuan Basin (Chuanxi Depression), while the exploration of the same formation in the middle segment of the Chuanxi Depression has not been carried out. In order to accelerate the ultra-deep marine natural gas exploration of the Qixia Formation, based on a large number of outcrops around the middle segment of the Chuanxi Depression, combined with seismic and drilling data and previous research results, this study systematically combed the oil and gas geological conditions of the Qixia Formation and comprehensively analyzed its exploration potential. Results show that the Qixia Formation in the study area has comparable sedimentary background as the north and south segments of the Chuanxi Depression, and is a platform margin sedimentary facies with superior reservoir conditions. Moreover, the Qixia Formation in the study area is connected with the hydrocarbon generation center of the Cambrian Qiongzhusi Formation by source faults. The tight limestone and shale of Permian and the gypsolyte of Triassic can be potential excellent cap rocks. Therefore, the source-reservoir-cap assemblage of the Qixia Formation in this area is preferential for large-scale hydrocarbon accumulation.

Keywords

• petroleum exploration potential
• dolomite reservoir
• platform margin
• qixia formation
• permian
• middle segment of chuanxi depression
• sichuan basin