微孔道中残余油膜受力与变形的数值计算

The numerical calculation about the stress and deformation of residual oil in the micropore

为了分析流体的粘弹性和岩石的润湿性对微孔道中残余油膜受力和变形的影响,从水动力学角度探索聚合物溶液的驱替机理,结合连续性方程、运动方程、上随体Maxwell本构方程建立了粘弹性流体在微孔道中的流动方程,运用数值分析对流场进行了计算,得到了聚合物溶液作用在不同润湿性岩石表面上的残余油膜的受力及变形情况。计算结果表明:与无弹性的驱替液相比,聚合物溶液作用在残余油膜上的法向偏应力发生了突变,同时聚合物溶液的粘弹性越大,作用在残余油膜上的法向偏应力越大,残余油膜的变形就越大;对于不同润湿性的岩石,亲油岩石表面的油膜比亲水的变形稍大一些,为下一步计算特殊边界条件的残余油的受力与变形及残余油膜的破裂问题奠定了基础。

In order to analyze the stress and deformation of residual oil film in the micro pore that is affected by the visco-elasticity of the fluid and the wettability of the rock,and the hydrodynamics displacement mechanism is explored from the viewpoint of hydrodynamics,which is that the residual oil film is displaced by the elasticity of polymer solution.The viscoelastic fluid flow equation is established in the micro pore by choosing continuity equation,momentum equation,the upper convected Maxwell constitutive equation,the flow field is obtained by using the method of numerical analysis,and the stress and deformation,which polymer solution acts on the residual oil film in different wettability of the rock surface,are calculated.The results show that ? the normal deviatoric stress acting on the residual oil film,which is affected by viscoelastic driving fluid,has the abrupt change compared to that of inelastic driving fluid,meanwhile,the higher the visco-elasticity of polymer solution,the greater the normal deviatoric stress acts on the residual oil-film,the higher the deformation ;for the different wettability of the rock,the deformation of the residual oil film on oil wet surface is slightly larger than that of the water wet surface,which lays the foundation for the next calculation of the stress,deformation and breakup of residual oil about the special boundary conditions.