The Key Fundamentals for the Efficient Exploitation of Shale Oil and Gas and Its Related Challenges

This paper identifies and discusses the multiple geologic engineering challenges involved in shale gas exploitation which include reservoir characterization, safe and fast drilling, environmentally-friendly and efficient exploitation, and it puts them within a context of China’s experience in exploring for and exploiting shale gas.The paper elaborates upon the key fundamentals, which include geologic mechanical behavior and prediction theories of non-linear shale engineering, safe and quality shale oil and gas well drilling theories based on multiple coupling, dynamic and random fracture control mechanisms and non-aqueous fracturing technologies of shale beds, and multiscale seepage characteristics and exploitation theories of shale oil and gas. The following advanced theoretical issues should be solved as soon as possible. It was necessary to investigate the evolution rules of physical, chemical and mechanical properties of shale reservoirs and carry out mathematical characterization, analyze the interaction between discontinuous surrounding rocks and drilling and completion fluids under multiple coupling conditions, develop dynamic and random fracture control methods, long-term effective diverting mechanisms and non-aqueous fracturing technologies for shale reservoirs, explore micro-nano scale adsorption and desorption mechanisms of shale, and study multi-phase seepage theories with upscaling and multiple coupling. The paper concludes with a summary of research progress and development trends in the key advanced mechanical issues.This paper serves as a reference and guidance for the scientific and efficient development of shale oil and gas in China.