超临界CO_(2)压裂物理模拟实验研究进展

Advancements in Supercritical CO_(2) Fracturing Physical Simulation Experiments

超临界CO_(2)(SC-CO_(2))压裂技术是一种极具潜力的新兴非常规油气储层增产技术,该技术不仅可有效避免传统水力压裂引发的地层损害、环境污染、水资源浪费等问题,还具有起裂压力低、成缝复杂等优势。SC-CO_(2)压裂实验是在室内开展SC-CO_(2)压裂工艺研究、压裂增产机理认识和总结的重要技术手段。综述SC-CO_(2)压裂实验研究进展,以指导SC-CO_(2)压裂技术的发展。首先,介绍室内SC-CO_(2)压裂实验系统的组成及功能,针对实验装置存在的不足提出建议。然后,归纳分析SC-CO_(2)压裂实验研究成果,认为SC-CO_(2)渗透性强,因此相较于水力压裂其起裂压力低,同时SC-CO_(2)能够沟通岩石内部的微裂缝和微孔隙,促进复杂裂缝网络的形成。最后,总结各项实验研究所得的裂缝内SC-CO_(2)携支撑剂运移规律。研究表明,SC-CO_(2)携支撑剂的运移规律与水基压裂液相似,但运移效果稍差之。目前,需加强SC-CO_(2)携支撑剂运移室内实验研究,以进一步优化SC-CO_(2)压裂的工艺参数。

Supercritical CO_(2)(SC-CO_(2))fracturing technology represents a highly promising emerging technique for enhancing production in unconventional oil and gas reservoirs.This technology not only effectively avoids issues such as formation damage,environmental pollution,and water resource depletion caused by traditional hydraulic fracturing but also offers advantages such as lower initiation pressure and complexity in fracture propagation.SC-CO_(2) fraturing experiment in an important technical means for conducting research on SC-CO_(2) fraturing technology,understanding and sumarizing the mechanism production increase.Therefore,this review discusses advancements in SC-CO_(2) fracturing experiments aimed at guiding the development of SC-CO_(2) fracturing technology.Firstly,the composition and functionalities of the laboratory-scale SC-CO_(2) fracturing experimental system are introduced,along with suggestions for addressing existing shortcomings in the experimental setup.Secondly,an analysis of research findings from SC-CO_(2) fracturing experiments is presented.It is observed that SC-CO_(2) exhibits lower initiation pressure compared to hydraulic fracturing due to its enhanced permeability.Additionally,SC-CO_(2) has the capability to interact with the internal microcracks and micropores of rocks,promoting the formation of complex fracture networks.Lastly,insights gained from experimental studies on the transport of SC-CO_(2) with proppants within fractures are summarized.The result indicates that the transport behavior of SC-CO_(2) with proppants is similar to that of water-based fracturing fluids,albeit less effective.At present,it is necessary to strengthen laboratory experimental studies on the transport of SC-CO_(2) with proppants to further optimize process parameters for SC-CO_(2) fracturing.