弱胶结油藏大孔道出砂的渗流与管流耦合模型

COUPLED MODEL OF SEEPAGE AND PIPE-FLOW FOR SAND PRODUCTION FROM BIG CHANNEL IN UNCONSOLIDATED RESERVOIR

将渗流力学、岩石力学、流体力学知识相结合,建立了弱胶结油藏大孔道出砂的渗流与管流耦合模型,并进行了实例计算。油藏渗流模型主要基于达西定律,并且考虑了储层的可压缩性。将大孔道中的油藏流体与砂粒看作单分散的、稀释的悬浮液。考虑砂粒在大孔道中的沉降及液固两相流之间的相互作用,基于Navier-Stokes方程推导了油藏流体-砂粒两相运动的控制方程。其中,出砂流速门槛值和砂粒剥落本构方程通过实验方法确定,油藏流体渗流与大孔道管流之间通过压力和流量关系进行耦合。最后,通过计算研究了矩形区域内-注-采情况下大孔道的延伸情况,得到了开发过程中流场压力分布图和累计出砂量变化曲线,分析了油藏流体粘度、注采速度对出砂的影响。

A coupled model of seepage and pipe-flow for sand production from big channel in unconsolidated reservoir is deduced based on fluid mechanics and rock mechanics. The fluid flow in reservoir is assumed to obey Darcy's law and mass conservation law. The flow in big channel is fluid-solid two-phase flow, and it observes Navier-Stokes equations. The coupled relations between seepage and pipe-flow are obtained based on flux and pressure conditions. Threshold sand-production flow rate and sand flaking equation are given by experimental results. Using the above model, big channel propagating in a rectangle zone is simulated, in which a production well and a water well are located. Through simulation, the pressure distribution in flow filed and sand-production curves are achieved. According to simulation results, influencing factors of sand production, such as fluid viscosity and production rate, are analyzed.