The Study Of Seepage Flow Law On Polymer Enhanced Foam Flooding

Polymer enhanced foam flooding is a new tertiary oil recovery technique, which plays a very important role in a world with the rising oil shortages and the increasing difficulty of exploitation. Therefore, a series of studies and field experiments on foam flooding has been done by scholars of the world. However, since the Seepage mechanism of foam in the porous medium is complex, How to accurately describe the Seepage mechanism of foam in the porous medium and clearing up the seepage flow law on polymer enhanced foam flooding is the key issue of studying on the polymer enhanced foam flooding. Therefore, this paper carried out the study on the seepage flow law of the polymer enhanced foam flooding, which accomplished the following work:Firstly, physicochemical properties of each component in polymer enhanced foam flooding system, generating mechanism of the foam, coalescence mechanism of the foam, oil-displacement mechanism and migration mechanism of the foam were studied. The seepage flow mechanism of polymer enhanced foam flooding was analyzed.Secondly, the mathematical model for multiphase-multicomponent flow of polymer enhanced foam flooding was established, considering the influence of generating and coalescence mechanism of the foam, the effects of foam on permeability, the effects of foam on viscosity, the effects of foam on shear thinning of foam, viscoelasticity, shear thinning, adsorption, dispersion, inaccessible pore volume, permeability reduction and residual oil satruration of polymer, the adsorption, the dispersion and the residual oil satruration reduction of surfactant, the model was been derived by the finite difference method.Thirdly, study on adaptability of polymer enhanced foam was researched on, the influence of the surfactant concentration, polymer concentration and the gas-liquid ratio on resistance factor and recovery ratio, polymer enhanced foam formula system was optimized. The influence of the injection parameters, such as injection rate, injection timing and injection quantity on water cut and recovery ratio, the injection parameters of polymer enhanced foam flooding was optimized.Finally,the generating rate and coalescence rate of polymer enhanced foam in the porous medium were calculated, the distribution of foam generating and coalescence rate between the injection and the recovery were provided, the enhancing effect of polymer on foam flooding system was studied, then the foam flooding region was separated according to the distribution of foam net generating rate. The pressure dynamic curves of polymer enhanced foam flooding were drawed, the changes on pressure and pressure derivative of Water flooding, single foam flooding and polymer enhanced foam flooding were compared, at the same time, the Influencing factors of the pressure dynamic curves were analysed.