基于GPD3D的水力压裂储层页岩裂缝网络形成机制研究

页岩气的高效开发是优化能源结构、实践绿色低碳的重要战略方针，其过程中的水平井压裂裂缝网络形成机制逐渐发展为国际岩石力学领域极富挑战的前沿课题。本项目基于储层页岩的物性表征，以压裂模式、射孔布设、应力组合过程中的裂缝演化机理为研究主线，采用试验、理论分析和三维数值模拟相结合的方法，分析页岩起裂特征及水力裂缝遇层理、天然裂缝的扩展模式，提出考虑流-固-损伤耦合的三维广义粒子动力学方法（GPD3D），探讨基于并行计算架构（CUDA）的高效数值模拟技术，建立压裂过程诱发页岩渗流-损伤-破裂成缝的三维裂缝扩展模型，阐明与天然裂缝相互作用的多水力裂缝竞争演化机理，深入研究多因素协同控制的水平井压裂裂缝网络形成规律及其定量表征，开展典型页岩气开采中的压裂裂缝网络分析与优化，揭示水力压裂储层页岩的复杂裂缝网络形成机制。研究成果可为水平井压裂缝网评价、压裂方法优化及储层开发预测提供重要的理论依据和技术支撑。

The efficient development of the shale gas is a significant strategic policy to optimize the energy structure and realize the the green low carbon, and the formation mechanism of the fracture network induced by horizontal well fracturing is gradually becoming the more challenged issue in the field of the international rock mechanics. Based on the physical characterization of the real shale in reservoirs, the project focuses mainly on the fracture evolution mechanism induced by the combined effect of the fracturing modes, perforation arrangement and stress conditions. And the shale initiation characteristics and propagation variation encoutering the bedding and natural fractures are investigated using the laboratory tests, theoretical analysis and 3-Dimensional numerical simulation methods. And then, the method named 3-Dimensional General Particle Dynamics (GPD3D) considering fluid-solid-damage coupling effect is proposed and the efficient numeircal modelling technique based on Compute Unified Device Architecture (CUDA) is also discussed. In addition, the 3-Dimensional fracture evolution model describing the fluid-damage-failure-fracture process of the shale is established to illuminate the propagation mechanism of multi-factures when fracturing competitively. Moreover, the formation variation of the fracture network and corresponding quantitative characterization are also deeply investigated considering multi-factor cooperation while horizontal well fracturing. And also, the fracture network in the process of the real shale gas exploitation has been analyzed and optimized to reveal the formation mechanism of complex fracture network for the fractured reservoir shale. The above research achievements would provide an important theoretical basis and technical support for the fractures assessment, optimization of fracturing method and prediction of the reservior exploitation.