The need for high performance polymers used in chemical EOR is increasing in some oil fields, especially in China. It is a challenging issue to simulation the flow of polymer solution through pores. What make the complexity of this problem are the multiple physical phenomenons that the transformations of macromolecule interact with the macroscopic flow. Both molecular and hydrodynamic effects are of important at this scale, but not all of which can be resolved by the traditional continuum-based approaches that involves solution of the Navier-Stokes equations with a phenomenological constitutive equation. Microscopic molecular dynamics, on the other hand, requires excessive calculation time before macroscopic effects become visible, and therefore dissipative particle dynamics (DPD) is used to simulate the rheological properties of polymer solution in our work. As a particle-based mesoscopic method, the DPD method is appropriate to study complex fluids including polymer or surfactant [1]. In this study, the polymer molecule was represented with a chain of beads connected with finite extensible nonlinear elastic (FENE) springs that led to viscoelastic flow, and the periodic Poiseuille flow method proposed by Backer et al [2] was applied to measure the viscosity of simulation system. The rheological properties of linear, branch- and star- polymers solution were simulated, and some factors including molecular weight, molecular topology and concentration were evaluated quantitatively. Besides that, the radius of gyration of polymers was recorded in simulations. In our opinion, the numerical instabilities of many conventional methods can be avoided in this approach, and the simulation results gave a clear physical insight into the flow of polymer solution.

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