The generation method of three-dimensional fractal discrete fracture network (FDFN) based on multiplicative cascade process was developed. The complex multi-scale fracture system in shale after fracturing was characterized by coupling the artificial fracture model and the natural fracture model. Based on an assisted history matching (AHM) using multiple-proxy-based Markov chain Monte Carlo algorithm (MCMC), an embedded discrete fracture modeling (EDFM) incorporated with reservoir simulator was used to predict productivity of shale gas well. When using the natural fracture generation method, the distribution of natural fracture network can be controlled by fractal parameters, and the natural fracture network generated coupling with artificial fractures can characterize the complex system of different- scale fractures in shale after fracturing. The EDFM, with fewer grids and less computation time consumption, can characterize the attributes of natural fractures and artificial fractures flexibly, and simulate the details of mass transfer between matrix cells and fractures while reducing computation significantly. The combination of AMH and EDFM can lower the uncertainty of reservoir and fracture parameters, and realize effective inversion of key reservoir and fracture parameters and the productivity forecast of shale gas wells. Application demonstrates the results from the proposed productivity prediction model integrating FDFN, EDFM and AHM have high credibility.

开发了基于乘法级联过程的三维分形离散裂缝网络(FDFN)生成方法。通过人工裂缝模型与天然裂缝模型的耦合表征压裂后页岩中复杂的多尺度裂缝系统。基于使用基于多重代理的马尔可夫链蒙特卡罗算法 (MCMC) 的辅助历史匹配 (AHM)，结合储层模拟器的嵌入式离散裂缝建模 (EDFM) 用于预测页岩气井的产能。采用天然裂缝生成方法时，可通过分形参数控制天然裂缝网络的分布，与人工裂缝耦合生成的天然裂缝网络可表征压裂后页岩中不同尺度裂缝的复杂系统。EDFM 网格少，计算耗时少，可以灵活表征天然裂缝和人工裂缝的属性，模拟基质细胞和裂缝之间的传质细节，同时显着减少计算量。AMH与EDFM的结合可以降低储层和裂缝参数的不确定性，实现关键储层和裂缝参数的有效反演和页岩气井产能预测。应用证明了所提出的结合 FDFN、EDFM 和 AHM 的生产力预测模型的结果具有很高的可信度。并模拟基质细胞和裂缝之间的传质细节，同时显着减少计算。AMH与EDFM的结合可以降低储层和裂缝参数的不确定性，实现关键储层和裂缝参数的有效反演和页岩气井产能预测。应用证明了所提出的结合 FDFN、EDFM 和 AHM 的生产力预测模型的结果具有很高的可信度。并模拟基质细胞和裂缝之间的传质细节，同时显着减少计算。AMH与EDFM的结合可以降低储层和裂缝参数的不确定性，实现关键储层和裂缝参数的有效反演和页岩气井产能预测。应用证明了所提出的结合 FDFN、EDFM 和 AHM 的生产力预测模型的结果具有很高的可信度。