非常规储层CO2前置压裂技术研究进展

Research Progress on CO2 Pre-Fracturing Technology in Unconventional Reservoirs

  • 摘要: 研究非常规油气储层中压裂技术对于推动非常规油气资源的高效、环保开发具有重要意义。传统水力压裂技术在实际应用中面临高耗水量、储层伤害等问题,限制了其在特定油气藏中的适应性。CO2前置压裂技术作为一种新型的无水压裂技术,在非常规油气藏开发领域展现出广阔的应用前景。文章通过对国内外CO2前置压裂技术相关文献的系统梳理,围绕CO2前置压裂的压裂机理、工艺优化、CO2-岩石-原油相互作用机制、裂缝扩展规律及现场应用等方面进行了深入研究,重点分析了CO2在裂缝起裂、扩展及与原油相互作用过程中的特征,以及天然裂缝分布、CO2注入排量、地应力场、储层岩性等关键因素对CO2压裂效果的影响。研究表明:天然裂缝、地应力和施工排量是决定裂缝扩展形态与储层改造体积的关键因素;CO2进入储层后可与岩石发生物理化学作用,降低岩石力学强度,进一步促进裂缝扩展并形成高效油气流动通道;在页岩油、低渗透油藏和稠油等储层中,CO2前置压裂已展现显著增产效果,但其适用性机理及优化设计方法仍有待深入研究。文章总结了CO2前置压裂技术在非常规油气藏开发中的应用现状,并提出了未来CO2前置压裂技术的研究方向。

     

    Abstract: The advancement of fracturing technologies in unconventional reservoirs plays a crucial role in the efficient and environmentally friendly development of unconventional hydrocarbon resources. Traditional hydraulic fracturing faces challenges such as high water consumption and reservoir damage, which limit its applicability in specific reservoirs. CO2 pre-pad fracturing technology, as an innovative water-free fracturing technique, has shown promising potential in the development of unconventional oil and gas reservoirs. Through a systematic review of domestic and international literature on CO2 pre-fracturing technology, in-depth research was conducted in this study focusing on aspects such as the fracturing mechanism of CO2 pre-fracturing, process optimization, CO2-rock-crude oil interaction mechanism, fracture propagation law, and field applications. Emphasis was placed on analyzing the characteristics of CO2 during fracture initiation, propagation, and its interaction with crude oil, as well as the influences of key factors—including natural fracture distribution, CO2 injection rate, in-situ stress field, and reservoir lithology—on the CO2 fracturing effect. It has been demonstrated that natural fractures, in-situ stress conditions, and injection rate are the key factors controlling fracture propagation morphology and the stimulated reservoir volume. Once injected into the reservoir, CO2 interacts with the rock through physicochemical processes, whereby the mechanical strength of the rock is reduced, fracture propagation is further facilitated, and efficient hydrocarbon flow channels are generated. In shale oil, tight oil, and heavy oil reservoirs, significant production enhancement has been achieved by CO2 pre-pad fracturing; however, its applicability mechanisms and optimization design methods remain to be systematically investigated. The current status of CO2 pre-pad fracturing technology in unconventional reservoir development is summarized, and future research directions for CO2 pre-pad fracturing are proposed.

     

/

返回文章
返回