This work presents the development of a 3D hybrid coupled dual continuum and discrete fracture model for simulating coupled flow, reaction and deformation processes relevant to fractured reservoirs with multiscale fracture system, e.g., coal and shale, efficiently and accurately. In this hybrid model, the natural fracture network and coal matrix are described together by a dual continuum approach and the large fractures are represented explicitly by the discrete fracture approach. A combination of different types of elements is used for spatial discretization. Large fractures are discretised with lower-dimensional interface elements and continuum domains with higher-dimensional elements. The coupling between the two models is achieved via the principle of superposition. To reduce computational time of simulations for complex and large-scale problems, a hybrid MPI/OpenMP parallel scheme is implemented in this work. The developed model is applied to investigate coupled thermal, hydraulic, and mechanical processes associated with CO₂ sequestration and enhanced coalbed methane recovery. The results demonstrate capabilities of the model to adequately capture the effects of multiscale fracture system and their coupled behaviour during CO₂ injection and methane recovery from coal reservoirs. Performance of the proposed parallelisation scheme was tested by comparing computation times of serial and parallel implementations. A good performance improvement was achieved, the speedup using parallelized scheme reaches up to about 10 times along with satisfactory scalability for considered application example. The findings of this work support developments and improvements of efficient advanced numerical models to study coupled THCM behaviour in fractured porous geomaterials.

这项工作提出了一种 3D 混合耦合双连续体和离散裂缝模型的开发，用于高效准确地模拟与具有多尺度裂缝系统的裂缝储层相关的耦合流动、反应和变形过程，例如煤和页岩。在这个混合模型中，天然裂缝网络和煤基质通过双连续方法一起描述，大裂缝通过离散裂缝方法明确表示。不同类型元素的组合用于空间离散化。大裂缝用低维界面元素离散化，连续域用高维元素离散化。两种模型之间的耦合是通过叠加原理实现的。为了减少复杂和大规模问题的模拟计算时间，在这项工作中实现了混合 MPI/OpenMP 并行方案。开发的模型用于研究与 CO 相关的耦合热、水力和机械过程₂封存和提高煤层气回收率。结果表明，该模型能够充分捕捉多尺度裂缝系统的影响及其在 CO ₂注入和煤储层甲烷采收过程中的耦合行为。通过比较串行和并行实现的计算时间来测试所提出的并行化方案的性能。实现了良好的性能改进，使用并行化方案的加速比达到了大约 10 倍，并且对于所考虑的应用示例具有令人满意的可扩展性。这项工作的结果支持开发和改进有效的高级数值模型，以研究断裂多孔地质材料中的耦合 THCM 行为。