Shale gas favorable area prediction of the Qiongzhusi Formation and Longmaxi Formation of Lower Palaeozoic in Sichuan Basin, China

The Qiongzhusi Formation of the Lower Cambrian and Longmaxi Formation of the Lower Silurian are important gas source rocks in Sichuan Basin, with widespread gas shows in conventional oil exploration. Previous research has shown a bright future of shale gas development of the two reservoirs. Furthermore, in the early stage of exploration, deep research about the favorable area of the reservoir instead of the whole area can not be exaggerated. At present, many researchers have studied the reservoir characteristics and predicted the prospective area used methods which are imperfect and inconsistent. The purpose of this paper is to select the good exploration area using the method that had been used in Barnett shale by the U.S. Geological Survey in 2004. After systematically studying the details of the selected area of Barnett shale in Fort Worth Basin and considering the characteristics of Sichuan Basin, this paper chose thickness, totol organic carbon content, vitrinite reflectance and burial depth to determine the favorable area and extended area of the two reservoirs in Sichuan Basin. The result of this study indicated that both the best exploration area and the extended area of the Qiongzhusi Formation are within the border of Chengdu-Leshan-Ziyang-Neijiang and that of Longmaxi Formation are located around Zigong-Yibin area.