低渗透储层超临界CO_(2)压裂裂缝起裂与扩展机制研究进展

号:1671-4172(2024)06-0070-14 Research progress of fracture initiation and propagation mechanism in supercritical CO_(2)fracturing of low-permeability reservoirs

为解决传统水力压裂在煤层气和页岩气开采中带来的环境和地层损害问题,超临界CO_(2)(SC-CO_(2))压裂技术凭借低黏度、高扩散性及无水特性,逐渐成为一种有效替代方案。通过综述实验与数值模拟的最新进展,探讨了该技术在裂缝起裂与扩展中的作用机制,重点分析了裂缝起裂压力、扩展模式及其影响因素。研究结果表明,超临界CO_(2)压裂能够在较低起裂压力下形成复杂的裂缝网络,且应力状态、温度以及天然裂缝等因素对裂缝的起裂和扩展产生显著影响。并针对现有研究在精确模拟CO_(2)流动、相变效应及其与天然裂缝相互作用的复杂影响方面存在的不足,提出了优化建议与未来展望,以期为超临界CO_(2)压裂技术的优化升级与广泛应用提供理论支持和实践指导。

To address the environmental and formation damage caused by traditional hydraulic fracturing in coalbed methane and shale gas extraction,supercritical CO_(2)(SC-CO_(2))fracturing technology has emerged as an effective alternative due to its low viscosity,high diffusivity,and waterless nature.This paper reviews recent advancements in experiments and numerical simulations to explore the mechanisms of fracture initiation and propagation in this technology,with a focus on analyzing fracture initiation pressure,propagation patterns,and influencing factors.The findings show that SC-CO_(2)fracturing can generate complex fracture networks at lower initiation pressures,with stress conditions,temperature,and natural fractures significantly impacting fracture initiation and propagation.Additionally,the paper highlights existing limitations in accurately simulating CO_(2)flow,phase transitions,and its interactions with natural fractures,offering optimization suggestions and future perspectives.