The formation of a complex hydraulic fracture network in a naturally fractured reservoir is strongly influenced by the distribution of pre-existing natural fractures and the interaction performance of multiple fractures. A numerical model containing a large number of (3120) pore pressure cohesive elements is built for modelling the randomly crossing and branching of hydraulic fractures. The effects of the distribution and cementation strength of pre-existing natural fractures on the propagation of complex hydraulic fracture networks are investigated. The interaction of multiple fractures and the interference effect among adjacent hydraulic fracture branches are also interpreted. The natural fracture is fractured before the hydraulic fracture tip reaches it when the cementation strength of natural fracture is low. The complexity of the hydraulic fracture network could be significantly affected by the cementation strength of pre-existing natural fractures and their distributions. Complex hydraulic fracture networks require much higher injection pressure than that for relatively regular fractures. Hydraulic fracture branches restrict the development of the fracture in length, but promote the formation and development of the complex hydraulic fracture network.

天然裂缝性储层中复杂的水力裂缝网络的形成受先前天然裂缝的分布以及多条裂缝相互作用的影响很大。建立了包含大量（3120）孔隙压力内聚元素的数值模型，以对水力压裂的随机交叉和分支进行建模。研究了既有天然裂缝的分布和胶结强度对复杂水力裂缝网络扩展的影响。还解释了多个裂缝的相互作用以及相邻水力裂缝分支之间的干扰效应。当天然裂缝的胶结强度低时，天然裂缝在水力压裂尖端到达之前就破裂了。先前存在的天然裂缝的胶结强度及其分布会严重影响水力压裂网络的复杂性。复杂的水力压裂网络需要比相对规则的压裂高得多的注入压力。水力压裂分支在长度上限制了裂缝的发展，但促进了复杂的水力压裂网络的形成和发展。