页岩水力压裂过程水基润滑摩擦行为及作用机制研究

Horizontal multistage fracturing technique has become a most popular and efficient approach to produce natural gas from shale reservoir. The development of natural gas from shale reservoir in China frequently encounters bottlenecks due to the lack of systematic and in-depth understandings on the underlying mechanisms and theoretical guidance. Towards solving these problems, the present project will carry out investigations to actions and mechanism of water-based lubrication in the process of fractures propagation in shale-gas reservoir. In this project, a friction performance testing platform and a particle actions in situ observation testing platform will be develop. Using the comprehensive testing platform, the frictional sliding characters of shale and its influencing factors will be investigated, the moving and evolution behavior and of particles in the contact region will be researched, and the frictional characters between shale and particles will be studied. Based on multi-disciplines of tribology, surface and interface science, material, and chemistry, mechanism of particle and shale under water-based lubrication will be constructed. Thereby, theoretical supports will be provided for producing natural gas from shale reservoir.

水平井分段压裂已成为高效开发页岩气的重要手段之一。由于缺乏系统深入的机理研究和理论指导，中国页岩气开发频繁遇到技术瓶颈。本项目针对这些问题，开展页岩水力压裂过程裂缝微间隙水基润滑行为及作用机制研究, 主要内容包括：研制水基溶液润滑下岩石摩擦滑动综合试验平台和支撑剂颗粒运动在线观测系统；利用所研制平台，研究压裂液基液润滑下页岩摩擦滑动特性及其稳定性，研究微间隙中压裂液基液润滑下支撑剂颗粒运移规律，研究压裂液基液润滑下单个支撑剂颗粒和页岩表面间摩擦特性。在摩擦学、表界面科学学、材料学和化学等多学科综合交叉的基础上，揭示微间隙中压裂液基液、支撑剂颗粒和页岩之间的相互作用机制，为页岩气开发提供理论支持。

水平井分段压裂已成为高效开发页岩气的重要手段之一。页岩水力压裂过程支撑剂颗粒在细小裂缝移动规律将决定填充裂缝的效果，最终决定裂缝的导流能力和最终压裂的效果。为了研究支撑剂颗粒在页岩裂缝中滑动摩擦学行为，本项目研制出水基润滑下颗粒-颗粒摩擦试验台和颗粒-岩石摩擦试验台，在摩擦学、表界面科学学、材料学和化学等多学科综合交叉的基础上，研究了页岩水力压裂过程水基润滑摩擦行为，发现了压裂液基液润滑下页岩滑动摩擦特性和规律，揭示出微间隙中压裂液基液、支撑剂颗粒和页岩之间的相互作用机制。相关研究成果在国内外摩擦学和机械工程主流学术期刊发表高水平论文8篇，其中包括Tribology International 4篇、Tribology Letters 2篇、Friction 1篇以及机械工程学报1篇。本项目研究成果为水力压裂的实际应用和建模分析提供很好的参考系数和理论依据。