页岩储层甲烷原位燃爆压裂理论与技术研究进展

Shale gas is generally stored in dark mudstone, high-carbon mudstone and other gas-producing rocks in adsorbed and free states. It is a clean and efficient energy resource. Compared with conventional natural gas reservoirs, shale gas reservoirs generally have low porosity and low permeability. Using fracturing technology to improve shale gas recovery rate is a key research direction for China's energy development during the 14th Five-Year Plan period. This paper proposes an innovative in-situ methane deflagration fracturing technology for shale reservoirs. This technology utilizes the in-situ desorbed methane gas and injected combustion-assisting agents to cooperatively deflagrate and generate high-temperature and high-pressure gas to impact and fracture the shale reservoir, creating 3D fracture networks to provide efficient migration pathways for shale gas. The paper comprehensively analyzes the conception and feasibility, key scientific issues, and main research directions of the in-situ methane deflagration fracturing technology. It includes three key research contents: the in-situ synergistic ignition mechanism and pressure wave propagation characteristics of methane-combustion assisting a-gent, the transient impact dynamics response and control mechanism of methane deflagration on wellbore media, and the multi-stage pulsed deflagration fracturing for hierarchical 3D fracture network construction and evaluation technologies. These basically cover the latest progress in the current theoretical and technical research on methane in-situ deflagration fracturing. The study believes that the methane in-situ deflagration fracturing method does not require a lot of water and fracturing fluids, nor does it involve the ground transportation and underground placement and mixing of explosives. Its safety, economic and environmental advantages are very significant. It is a forward-looking and revolutionary technology that will help a-chieve innovative breakthroughs in China's shale gas development technologies.