为准确判别煤系复合储层合层压裂过程中，水力裂缝遇到层间界面时的扩展路径，基于流体流动和固体弹性变形理论及水力裂缝遇到天然裂缝时扩展路径的判别准则，建立了复合储层水力合层压裂裂缝穿层扩展的判别模型；模型重点考虑了压裂液注液速率和黏度对水力裂缝穿层扩展的影响，给出了水力裂缝穿层扩展与沿界面扩展的临界缝压，通过比较井筒水压与2个临界缝压的大小，判断裂缝的扩展行为；通过比较模型的预测结果、压裂试验数据及现场压裂结果的差异，验证了模型的准确性。以临兴区块石盒子组砂-泥岩复合储层为地质背景，研究了注液参数对水力裂缝穿层扩展的影响。结果表明：注液速率及压裂液黏度能够直接影响井筒内的水压，进而改变裂缝扩展路径；注液速率与压裂液黏度越大，越有助于水力裂缝穿层，其中注液速率的影响程度更大；现场压裂施工过程中，主要通过提高压裂液注液速率达到穿层压裂的目的。

Based on the theory of fluid flow and solid elastic deformation as well as the criterion of the propagation path when hydraulic fracture meets natural fracture, a model for the propagation of hydraulic fracture through layer is established in order to accurately judge the propagation path when hydraulic fracture meets interlayer interface in coal measure composite reservoir fracturing process. The model mainly considers the effect of injection rate and viscosity of fracturing fluid on the propagation of hydraulic fracture through the layer, and gives the critical fracture pressure of the propagation of hydraulic fracture through the layer and along the interface. The propagation behavior of the fracture is judged by comparing the wellbore water pressure with the two critical fracture pressures. The accuracy of the model is verified by comparing the prediction results of the model, the fracturing test data and the on-site fracturing results. The accuracy of the model is verified by comparing the prediction results of the model, the fracturing test data and the on-site fracturing results. The results show that injection rate and fracturing fluid viscosity can directly affect the water pressure in the wellbore, and then change the fracture propagation path. The greater the viscosity between injection rate and fracturing fluid, the more beneficial it is for hydraulic fracture penetration, and the greater the influence of injection rate is. In the process of in-situ fracturing, the purpose of penetrating fracturing can be achieved mainly by increasing the injection rate of fracturing fluid.