Progress of basic theories and technologies of safety pre-control in in-situ pyrolysis of oil-rich coal

LUO Zhenmin; ZHOU Shangyong; WANG Shuangming; ZHOU Anning; WANG Tao; SU Bin; LI Ruikang; MENG Fandong; LI Yiming; WANG Jiaxuan; ZHANG Lidong; YANG Xi; WU Gang

doi:10.13225/j.cnki.jccs.2025.0556

Abstract：Against the backdrop of escalating global energy crises and driven by the national strategic imperative to en-hance domestic oil and gas supply,in-situ pyrolysis technology for oil-rich coal has garnered unprecedented attention in China due to its advantages of lower pollution,minimal geological disturbance,and high potential for large-scale deploy-ment.Nevertheless,the inherent challenges of drilling-based in-situ pyrolysis including non-visualized processes,person-nel inaccessibility,and complex subsurface reaction conditions,pose significant safety risks to coal production,constitut-ing critical constraints for large-scale technological deployment.A comprehensive understanding of oil/gas production characteristics and their combustion/explosion hazards,the regulation mechanisms of the in-situ pyrolysis reactions,the fracture propagation laws during pyrolysis,the oil/gas migration mechanisms,as well as the environmental impacts and corresponding prevention/control technologies,forms the essential foundation for ensuring stable operation and safety risk mitigation in in-situ pyrolysis of oil-rich coal.Nevertheless,key knowledge gaps persist:The characteristics of oil/gas pro-duction and their associated combustion/explosion risks remain unclear;The heat transfer laws and transport models with-in the pyrolysis zone are inadequate;and the migration patterns of oil/gas products under multi-field coupling effects are not yet fully elucidated.Building upon the refinement of these fundamental theories,the development of fracture-sealing materials capable of simultaneously preventing gas escape and stabilizing overlying strata,the exploration of sealing tech-niques for discontinuous fracture spaces,the invention of shielding/isolation technologies for pyrolysis reaction chambers,the advancement of an integrated air-space-ground multi-dimensional monitoring system with efficient data collection and processing,and the establishment of an intelligent and automated control system for the in-situ pyrolysis reaction are cru-cial for providing safety assurances for the technology's promotion.Although relevant theoretical,technological,and equipment research has been conducted globally,it has not yet fully addressed the pre-control safety requirements of the in-situ pyrolysis process for oil-rich coal.