Complex fracture networks are easily developed along the horizontal wellbore during hydraulic fracturing. The water phase increases the seepage resistance of oil in natural fractured reservoir. The flow regimes become more intricate due to the complex fractures and the occurrence of two-phase flow. Therefore, a semi-analytical two-phase flow model is developed based on the assumption of orthogonal fracture networks to describe the complicate flow regimes. The natural micro-fractures are treated as a dual-porosity system and the hydraulic fracture with complex fracture networks are characterized explicitly by discretizing the fracture networks into multiple fracture segments. The model is solved according to Laplace transformation and Duhamel superposition principle. Results show that seven possible flow regimes are described according to the typical curves. The major difference between the vertical fractures and the fracture networks along the horizontal wellbore is the fluid “feed flow” behavior from the secondary fracture to the main fracture. A natural fracture pseudo-radial flow stage is added in the proposed model comparing with the conventional dual-porosity model. The water content has a major effect on the fluid total mobility and flow capacity in dual-porosity system and complex fracture networks. With the increase of the main fracture number, the interference of the fractures increases and the linear flow characteristics in the fracture become more obvious. The secondary fracture number has major influence on the fluid feed capacity from the secondary fracture to the main fracture. The elastic storativity ratio mainly influences the fracture flow period and inter-porosity flow period in the dual-porosity system. The inter-porosity flow coefficient corresponds to the inter-porosity flow period of the pressure curves. This work is significantly important for the hydraulic fracture characterization and performance prediction of the fractured horizontal well with complex fracture networks in natural fractured reservoirs.

在水力压裂过程中，沿水平井眼很容易形成复杂的裂缝网络。水相增加了天然裂缝性油藏中石油的渗流阻力。由于复杂的裂缝和两相流的发生，流态变得更加复杂。因此，基于正交裂缝网络的假设开发了半解析两相流模型来描述复杂的流态。天然微裂缝被视为双孔隙系统，具有复杂裂缝网络的水力裂缝通过将裂缝网络离散为多个裂缝段来明确表征。该模型是根据拉普拉斯变换和杜哈梅尔叠加原理求解的。结果表明，根据典型曲线描述了七种可能的流态。垂直裂缝和水平井筒裂缝网络之间的主要区别在于从次要裂缝到主裂缝的流体“进料流”行为。与传统的双孔隙度模型相比，所提出的模型中增加了天然裂缝伪径向流动阶段。含水量对双孔隙系统和复杂裂缝网络中的流体总流动性和流动能力有主要影响。随着主裂缝条数的增加，裂缝间的干扰增加，裂缝内的线流特征更加明显。次要裂缝数量对从次要裂缝到主裂缝的流体供给能力有重大影响。双孔隙系统中弹性储量比主要影响裂缝流动周期和孔隙间流动周期。孔隙间流动系数对应于压力曲线的孔隙间流动周期。这项工作对于天然裂缝性油藏中具有复杂裂缝网络的裂缝水平井的水力裂缝表征和性能预测具有重要意义。