黏弹性聚合物溶液不稳定渗流模型

Unsteady seepage flow model of visco-elastic polymer solution

针对计算黏弹性流体在多孔介质中的渗流阻力特性时 ,存在较大偏差的问题 ,考虑聚合物溶液黏弹性、吸附效应及注入液流变参数变化等因素 ,建立了黏弹性聚合物溶液不稳定渗流模型 .用有限差分法对其求解 ,绘制了相应地层压力的理论曲线 .分析了松弛时间、注入量、渗透率下降因数、注入液稠度系数以及幂律指数等参数对压力动态的影响 .结果表明 :注入井的井底压力及地层压力随着聚合物溶液的弹性效应、注入量、稠度系数、幂律指数的增加而增加 ;聚合物黏弹性的存在是造成注入压力升高的原因之一 ,黏弹性的影响主要表现在近井地带 ;在聚合物驱压力动态分析中 。

Because large deviation occurs when the flow resistance behavior of visco-elastic fluids is calculated, with the consideration of the visco-elasticity, the adsorption effect and the variation of rheological parameters of polymer solutions, the seepage flow model of visco-elastic polymer solutions is established. By the difference method it is solved. Then curves of formation pressure are drawn. The influences of the relaxation time, the injection rate, the permeability reduction coefficient, the consistency coefficient and the power-law exponent of the injected fluid on pressure performance are analyzed. This study shows that the bottom hole pressure of injection well and formation pressure increase with the increase of injection rate, permeability reduction coefficient, consistency coefficient, power-law exponent of the injected fluids. The existence of visco-elasticity is one of causes resulting in the rising of injection pressure. The effect of elasticity mainly exists near the well bottom. It is necessary to consider the visco-elasticity of non-Newtonian fluid in the analysis of pressure transient in the polymer flooding.