Polymer microsphere flooding is an effective enhanced oil recovery (EOR) technology. Its primary mechanism is characterized by a dynamic cycle of “migration, plugging, breakthrough, and remigration”, which enables effective in-depth profile control and selective plugging. However, constructing accurate mathematical models and obtaining stable numerical solutions for this process remain challenging. Based on the black-oil framework, a three-phase, five-component mathematical model is developed for water-microsphere dispersed system, including oil, gas, water phases and two microsphere components (pre-swollen and post-swollen), and accounting for swelling kinetics, adsorption, and water phase permeability reduction. The model is numerically solved using a fully implicit finite-difference scheme, and validated by numerical tests and a field-scale application. The numerical simulation results demonstrated an overall agreement rate of approximately 85% with experimental data. Mechanistic comparisons indicated that polymer microsphere flooding significantly improves sweep efficiency and oil recovery. Field-scale application further showed that polymer microsphere flooding, compared with conventional water flooding, increases the recovery factor by 3.49 percentage points, reduces the maximum water cut by about 9.34 percentage points, and raises the average daily oil production rate over the entire development period by 7.5 m3. The proposed model can provide theoretical basis for the field application of polymer microsphere flooding for in-depth profile control.
Xin et al. (Sun,) studied this question.