基于多孔介质中聚合物弹性的相渗曲线研究

A Study on Permeability Curve Based on Polymer Elasticity in Porous Media

聚驱相对渗透率曲线对进一步认识聚合物驱的渗流规律具有重要意义,但现有研究并未充分考虑聚合物在多孔介质中的弹性,因此对传统计算方法的聚合物弹性进行修正。设计了一种弹性恢复实验,测定消除弹性后的纯黏压差,来计算聚合物在岩芯中的弹性黏度。将聚合物的弹性以弹性黏度的形式引入相对渗透率曲线的计算。结果表明不考虑弹性黏度,计算的水相相对渗透率偏小。测定了不同分子量和不同浓度聚合物的相对渗透率曲线。结果表明分子量越大,弹性黏度越大;浓度越高,弹性黏度越大。弹性黏度的增大会使油相相对渗透率增大,水相相对渗透率降低,残余油饱和度也随之降低。另外,此方法与传统J.B.N.方法相比,计算的相对渗透率曲线不受到流速的影响,计算结果更加可靠。

The relative permeability curve of polymer flooding is of great significance for a further understanding of the flow characteristics of polymer in porous media.However,existing studies have not fully considered the elasticity of polymer in porous media.An elasticity recovery experiment was performed to measure the pure viscous pressure difference after eliminating elasticity and to calculate the elastic viscosity of the polymer in the core.The elasticity of the polymer was introduced into the calculation of the relative permeability curve in the form of elastic viscosity.The results showed that the calculated relative permeability of the water phase is smaller when the elastic viscosity is not considered.The relative permeability curves of polymers with different molecular weights and at different concentrations were determined.The results showed that the elastic viscosity was greater for a higher molecular weight and concentration.The increase in the elastic viscosity increases the relative permeability of the oil phase,decreases the relative permeability of the water phase,and decreases the residual oil saturation.In addition,compared with the traditional J.B.N.method,the relative permeability curve calculated by this method is not affected by the flow rate and the calculation results are more reliable.