缝洞型油藏溶洞内水驱流态研究

为研究缝洞型油藏溶洞中注水速度和黏度对水驱波及面积和油水界面的影响,利用Fluent数值模拟软件从流体力学角度对单缝洞油藏溶洞内流体流动进行了数值模拟,采用VOF模型对油水两项界面进行跟踪。研究发现,入口水速一定时,波及面积随着黏度的增大逐渐增大,油水界面呈对称均匀推进,黏度较小的原油水相会趋向中心线向洞口流动并产生漩涡,随着黏度逐渐增大,漩涡逐渐消失,驱替方式逐渐转变成活塞式驱替;原油黏度一定时,波及面积随着入口速度的增加而减小,油水界面呈对称趋势均匀推进,水速较大时水相会趋向中心线向洞口流动并有漩涡产生,随着入口水速增大,趋势逐渐明显。研究结果可为进一步完善缝洞型油藏溶洞内水驱过程中油水两相的流态分析提供参考。

Study on the flow of water drive in cavern of fractured-cave reservoirs

In order to study the influence of water injection speed and viscosity on water flooding sweep area and oil-water interface in fractured-cave reservoirs, Fluent numerical simulation software is used to simulate the fluid flow in single-fractured cave reservoirs from hydrodynamic point of view and VOF model is used to track the two interfaces of oil and water. The simulation results show that when the inlet water velocity is constant, swept area gradually increases with the increase of viscosity, and the oil-water interface is symmetrically and uniformly pushed forward. The smaller viscosity of the crude oil water will tend to flow toward the center hole and generate vortex. As the viscosity gradually increases, the vortex gradually disappears, and the displacement method gradually changes into piston displacement. When the viscosity of crude oil is constant, the sweep area decreases with the increase of inlet velocity, and the oil-water interface is symmetrically pushed forward uniformly. When the water velocity is fast, the water phase tends to flow toward the hole and generate vortex along the centerline with the increase of inlet water velocity, and the trend becomes obvious. The research results provide reference value for further improving the fluid-state analysis of oil-water two-phase in water-flooding process in cave-type reservoirs.