黏弹性流体在油藏孔隙模型中的流动阻力特性

Flow resistance of viscoelastic fluid through pore model of reservoir

采用上随体Maxwell本构方程描述流体的流变性,用数值方法研究了黏弹性流体在2类典型的油藏孔隙模型———孔喉模型和盲端模型中的流动阻力特性.分析了低雷诺数流动条件下,具有不同黏弹性质的流体在喉道和盲端附近的流动特性和压力损失规律.研究结果表明:黏弹性流体在孔隙变截面处的局部压力损失远高于相同流动条件下无弹性纯黏流体的局部压力损失;黏弹性越大,局部压力损失越大;黏弹性流体在变截面孔隙中的高局部压力损失是导致其在多孔介质中渗流阻力异常高的重要原因之一.

The upper-convected Maxwell model was used to describe the rheologicalproperty of fluid, and flow resistances of viscoelastic fluid in two typical pore models of reservoir pore throat model and dead end model were studied by numerical method. Mainly discussed were flow behavior and law of pressure loss near the entrance to throat and near the dead end at low Reynolds number. Results show that local pressure loss of viscoelastic fluid, where non-uniformity of pore's cross section occurs, is much higher than that of viscous fluid without elasticity, and the greater the fluid's viscoelasticity is, the higher the local pressure loss is. The high local pressure loss arising from the flow through pore with non-uniform cross section is one of the main reasons of unexpected high flow resistance of viscoelastic fluid percolating through porous media.