Abstract
Shale gas, an emerging unconventional gas source in recent decades, has received increasing attention worldwide. In the world, the technically recoverable reserves of shale gas resources in the US and China rank first and second, respectively. The ‘shale gas revolution’ in the US created an oversupply of liquefied natural gas and downward pressure on gas prices across the globe. In 2005, China introduced the concept of shale gas for the first time, started theoretical research and exploration and development of shale gas. After nearly 10 years of exploration, the preliminary evaluation and screening of favorable areas of China’s onshore shale gas potential was completed, and the extensive exploration and development of shale gas has been carried out. Supergiant Wufeng Formation – Longmaxi Formation shale gas province has been discovered in the Sichuan Basin, where Fuling, Changning and Weiyuan shale gas fields have a proven shale gas in place of 544.129 billion cubic meters in total, shale gas industrial exploitation has been realized with an annual output of over 7.8 billion cubic meters, making China the third shale gas production country in the world. With the increase of shale gas and conventional gas output, the Sichuan Basin is hopeful to become a ‘Southwest Daqing’ (i.e., ‘Southwest Gas Daqing’, in short ‘Southwest Daqing’ hereinafter) with an oil equivalent of 50 million tons.
Compared with the shale gas reservoirs in the US, these in China are more complicated in structural conditions, deeper in burial depth, larger in bidirectional stress difference, much higher in thermal evolution degree, greater in surface elevation difference and more difficult in development, and phase change occurs locally in high-quality shale reservoirs.
This Special Issue brings together selected researchers from CNPC to discuss shale brittleness, permeability, gas content, pore structure, major controlling factors for the formation and so on. The purpose of this Special Issue is to exchange scientific information, share details on facilities and expertise available for new research, learn and understand the needs of the industry, share major success experiences achieved, and provide important technical reference for other countries, such as Argentina, that are actively developing shale gas.