Research on the Plugging Method of Water Flooding Interference Wells in Water/Polymer Two-Flooding Combined Development Mode

The water/polymer two-phase flooding combination development mode has been widely applied in domestic oilfields. However, in the actual production process, water flooding interference wells can seriously affect the production effect of the water/polymer two-phase flooding combination development mode. Therefore, it is urgent to conduct research on the water flooding interference well plugging methods in the water/polymer two-phase flooding combination development mode. To address this issue, water flooding interference wells were first classified based on the positional relationship between water/polymer two-phase flooding oil and water wells. Then, four water flooding interference well plugging schemes were designed according to the water well plugging principles and numerical simulation methods. The influence of water flooding interference wells on the polymer flooding development effect under each scheme was analyzed and evaluated from the perspectives of remaining oil saturation and cumulative oil increment. Thus, the optimal plugging scheme and the water flooding interference well plugging method suitable for the water/polymer two-phase flooding combination development mode were obtained, that is, to plug all water injection wells and water flooding oil wells that interfere with polymer flooding development and have an effective connected thickness of more than 2 m per well. The field implementation effect of the plugging scheme in the target block shows that this plugging method can effectively improve the production effect of the water/polymer two-phase flooding combination development mode. The final recovery rate of the water/polymer two-phase flooding development mode after plugging is 12.15 percentage points higher than that before plugging.