报告题目：致密油藏地质力学耦合流动模拟（Geomechanics Coupled Flow Simulation for Tight Oil Reservoirs）
报 告 人：吴玉树 教授
讲座内容：Tight oil reservoirs have been receiving great attentions due to their large reserves and contributions to total oil production. However, fluid flow behavior in tight oil reservoirs is not still well studied or understood. Specific characteristics of tight oil reservoirs, such as nano-pore scale and strong stress-dependency, result in the complex subsurface fluid flow behaviors. The recent field observations and laboratory experiments indicate that effects of pore confinement and rock compaction have non-negligible impacts on the production performance of tight oil reservoirs. On the other hand, there are many approximations or limitations to model tight oil reservoirs under effects of pore confinement and rock compaction with current reservoir simulation techniques. In this talk, we discuss a compositional flow model, coupled with geomechanics with capabilities to describe complex fluid flow behavior in multiphase multi-component tight oil reservoirs. In the model, the pore confinement effect is represented by the effect of capillary pressure on vapor-liquid equilibrium (VLE) and modeled with the VLE calculation method. The fully coupled flow-geomechanical model is developed from the linear elastic theory for the poro-elastic system. The rock compaction is then correlated with stress-dependent rock properties, especially, stress-dependent permeability. The numerical studies demonstrate the effect of capillary pressure on VLE, and further on production performance in addition to the effect of rock deformation from substantial decrease in reservoir pore pressure or large increase in effective stress. The reduction of pore radius due to geomechanical effect could increase the capillary pressure, which enlarges the influence of capillarity on VLE and further suppresses bubble point pressure, influencing multiphase fluid flow as well as effective stress through the flow-stress coupling process.