A thermal-percolation model for the injection of cold polymer in fractal formation: Semi-analytical solution and influencing factor analysis

摘要

Polymer injection is a common method for enhancing oil recovery (EOR). In this process, tons of polymers are injected into formation. The flowing mechanism of polymer is important and complicated, which greatly influences displacement efficiency. Given that polymer is non-Newtonian fluid, the flow behavior is influenced by shear rate in pore space. During injection, the temperature of polymer increases, thereby affecting viscosity, which, in turn, influence the process. In this work, a temperature-dependent model for polymer injection in fractal-distributed matrix is built. Semi-analytical solutions for polymer transfer are derived using Laplace transform. These solutions are verified by public data. Finally, influencing factors on the polymer injection process were discussed, including temperature distribution, fractal parameters, non-Newton parameters and injection rates. The method provides a new way to analysis the thermal-percolation coupling process during polymer injection.