页岩储层内流体的流动具有多相、多尺度的复杂特征。然而目前针对页岩微纳米孔隙-裂隙系统内流动机理的研究主要集中于单相流体，而对其中油水两相流动机制的研究却鲜有报道。这使得页岩储层的多相渗流理论尚不清楚，宏观数值模拟、产能评价和开发动态优化等技术的准确性面临重大挑战，这已经成为制约页岩油工业化探索的瓶颈。本课题将综合利用分子动力学模拟方法和微流动实验开展页岩储层单个微纳米孔缝内油水两相的流动机制研究，阐明纳米尺度下接触角和界面张力随孔隙尺寸的变化规律，揭示微尺度效应对两相流体流动规律的影响并建立其数学表征模型。进而通过对页岩储集空间特征的分析构建数字岩心，定量描述孔隙-裂隙网络的连通性。在此基础上，建立页岩微纳米孔隙-裂隙系统内油水两相流动的模拟方法，探究其多相流动机理，表征油水的微观赋存状态，形成相渗曲线的预测技术，为页岩油科学有效的开发提供指导。

Fluid flow in shale formations is of the complex multiphase and multiscale characteristics. However, most of the current studies only concentrate on the single-phase flow in micro/nano- pore-microfracture systems of shale and the investigations on oil/water two-phase flow are very limited. Therefore, the physics of multiphase flow in shale formations is still ambiguous, and the effectiveness of some techniques, e.g., numerical simulation, performance evaluation, and production optimization, are challenged, which has been the bottleneck in the shale oil industrialization exploration. In this proposal, on the basis of molecular dynamics simulation and microfluidic experiment, the principles of water/oil two-phase flow in single micro/nano- pores and slits are studied, from which the variations of contact angle and interfacial tension against the size of nanopores are elucidated. The influence of microscale effect on the two-phase flow behaviors is also discussed and the corresponding mathematical model is built. Then the shale digital core model is constructed through the pore structure characterization and its network connectivity is quantified. Finally, the simulation method for oil/water two-phase flow in micro-/nano- pore-microfracture systems of shale is proposed. Based on the simulation results, the two-phase flow mechanism is explored, the microscopic distributions of water/oil are also characterized, and the prediction technology for relative permeabilities is put forward. These achievements will provide significant guidance for the scientific and efficient development of shale oil.