Numerical simulation of channel flow control with solid particles in carbonate fractured-vuggy reservoirs
摘要
Channel flow control (CFC) using solid particles is a newly emerged enhanced oil recovery (EOR) method for fractured-vuggy carbonate reservoirs. Currently, there lacks a reservoir simulation method for CFC, and its underlying mechanisms are not fully understood, resulting in a low success ratio. This study addresses these issues by proposing an efficient reservoir simulation method for CFC. The particles are conceptualized as a flowing phase. Oil-water and water-particle relative permeability model are derived assuming that the oil, water and particle phase are gravity segregated. A three-phase relative permeability model is then obtained via Stone’s method. Particle bridging phenomenon is incorporated into the model as a coefficient modifying the particle phase relative permeability. The method is validated against a CFC physical experiment, while case studies are conducted to investigate the underlying mechanisms of CFC. Results suggest that CFC can potentially improve oil recovery by 17%. The primary mechanism of CFC is particle bridging and the subsequent formation of plugging sites, which diverts injected water from preferential flow path and increases the swept volume. Localized water traps may also be formed, which further improve oil recovery. The location of plugging sites is crucial to the effectiveness of CFC. Key properties of CFC particles, such as their size and their concentration in injected suspension, must be optimized to achieve plugging at the desired location, as improper properties may result in significantly reduced recovery. The proposed method could play a significant role in the optimization of particle properties, which helps establish CFC as a commonly used EOR method for fracture-vuggy reservoirs. Future studies regarding the validity of gravity segregation assumption, effective viscosity of particle suspension and characterization of fractured pore space could further improve the accuracy and applicability of the method.