Stress Field Analysis around the Residual Oil Film in Formation Micro-pore with Polymer Flooding

Abstract

There is still nearly 40% of the crude oil remaining in the rock strata formed in residual oil after primary and secondary recovery. In order to improve oil recovery, to find the residual oil recovery method, to further improve the theoretical system of polymer flooding. Through the establishment of constitutive equation and flow equation and the boundary conditions suitable for describing the flow of viscoelastic fluid of polymer solution, applying computational fluid dynamics software, stress field around the residual oil film in formation micro-pore was calculated, stress was given around the residual oil film on the lipophilic rock surface with different situations of polymer solution, relationship between the viscoelasticity of polymer solution and the force around the residual oil film was analyzed. The results show that: The viscoelasticity of polymer solution is the main reasons for non-uniform stress distribution around the residual oil film, increasing the viscoelasticity of polymer solution, the stronger of the non-uniformity around the residual oil film, more beneficial to the deformation of residual oil film, further split and to reach the launch conditions of residual oil.