页岩气储层缝网压裂理论与技术研究新进展

为破解页岩气开发技术的瓶颈，借鉴北美地区页岩气开发已取得的成果与经验，基于我国自2005年来页岩气开发技术的探索与实践认识，并结合最新的研究成果，综合分析了页岩气储层缝网可压性评价、缝网扩展机理、压裂改造体积评价、压裂液研制等方面的理论新进展，主要包括：页岩脆性从建立矿物、力学的半定量门限值测定发展到整合了岩石组分、弹性力学、天然裂缝发育特征的综合评价；缝网扩展从定向延伸理论发展到随机天然裂缝分布下的缝网形成模拟；储层改造体积从依赖微地震监测等仪器技术发展到依托于离散裂缝网络、扩展有限元的数学理论评价方法；压裂液从滑溜水（减阻水）和线性胶压裂液体系的泛用到少水或无水等新型压裂液的研制与应用。在此基础上，指出了页岩气储层缝网可压裂性综合评价、深层页岩气压裂、页岩气压裂施工曲线诊断、页岩气重复压裂理论、新型压裂液体系研制及其返排控制等理论和技术所面临的挑战，并预测了相关技术的发展趋势，以期为我国后续页岩气高效开发提供理论与技术指导。

Latest research progresses in network fracturing theories and technologies for shale gas reservoirs

In view of the bottleneck of shale gas development technologies, the latest progresses in such theories on the fields like fracture network fracability evaluation, fracture network propagation mechanism, stimulated reservoir volume (SRV) evaluation and fracturing fluid research & development were analyzed comprehensively in reference to the existing achievements and experiences in North American shale gas reservoir development and based on the probes, practices and cognitions of shale gas development technologies in China since 2005. First, the study on the shale brittleness develops from the definition of mineral and mechanical semi-quantitative threshold measurement to a comprehensive evaluation which integrates rock constituents, elastic mechanics and development characteristics of natural fractures together. Second, the study on the fracture network development develops from the directional extension theory to the simulation of fracture network formation in the stochastic distribution pattern of natural fractures. Third, the study on SRV develops from the micro-seismic monitoring based instrument and technology to the mathematical theory evaluation method dependent on the discrete fracture network and extended finite element. And fourth, the study on fracturing fluids develops from the wide application of slick water (drag reducing water) and a linear gel fracturing fluid system to the development and application of novel fracturing fluids with little or no water. Then, the theoretical and technological challenges were pointed out, including the comprehensive fracability evaluation of reservoir fracture networks, the deep seated shale gas fracturing, the operation curve diagnosis of shale gas fracturing, the shale gas refracturing theory, and the research & development and flowback control of novel fracturing fluids. Finally, the development trend of related technologies was predicted so as to provide a theoretical and technical guidance for the efficient shale gas development in China in the future.