Exploration and Practice of Volume Fracturing in Shale Gas Reservoir of Sichuan Basin, China

Abstract The commercial development of natural gas in shale formations has been realized in U.S. The exploration and production of gas in shale is closely related to the progress of fracturing technology, and fracturing stimulation is becoming the key technology for developing gas production in shale. The shale development history in the U.S shows that horizontal well technology has increased shale exploration greatly. Now horizontal wells account for 94% of production, and the production is 2–4 times that of vertical wells in developing the Barnett shale in the U.S. The newly developed volume fracturing technology, especially volume fracturing in horizontal wells improves the stimulation results of horizontal wells and is becoming the main method of increasing production in shale. Compared with the shales in the North America, the shales in China exhibit a great difference in reservoir characteristics. The preliminary shale gas resource assessment in China shows that not only are the reserves in shale huge, but also the distribution is wide. There are two primary shale depositional environments in China, marine deposits and lacustrine deposits. The marine deposit shales are located in the south, north and northwest of China, with lacustrine deposit shales located in the northeast, north and northwest. From 2010, the exploration of shales in Weiyuan, Changning, Fushun and Zhaotong areas of the Sichuan basin started, with fracturing jobs in 7 vertical wells and 4 horizontal wells showing good results, which demonstrates the potential of shale gas exploration in China. This paper describes the exploration and practice of volume fracturing and supporting technology in shale gas reservoirs in the Sichuan basin. The fracturing results show that some obvious complex fracture network is formed in most wells. The practice of volume fracturing in shale in Sichuan Basin shows that parameter optimization, wellsite control and application of supporting technology based on reservoir character and job objective are the keys to volume fracturing. This paper presents the summary of development of volume fracturing of shale in China and discusses the next step considerations on the basis of the shale reservoir characteristics in Sichuan Basin.