Study on Injection Limit of Polymer Flooding in Ordinary Heavy Oil Reservoirs

In the long-term development of heavy oil reservoirs with water flooding, the injected water usually flows through the high permeability layer, resulting in significant invalid circulation. Polymer flooding can increase swept volume and improve oil displacement efficiency. Reasonable technical criteria for injecting polymers into ordinary heavy oil reservoirs have been proposed by numerical simulation using a typical actual well pattern. The impacts of polymer injection volume, polymer solution concentration, injection rate, number of injection slugs, interval time between injection slugs, polymer solution concentration of subsequent slugs, and injection methods were evaluated. The results showed a large polymer injection volume, polymer solution of 2,000 mg/L, an injection rate of 0.056 PV/a, multiple slugs, small intervals, lower polymer concentration of subsequent slugs, and simultaneous injection of multiple wells would yield better oil production by polymer flooding. The proposed reasonable technical criteria of polymer flooding can improve the development effect and guide the field operation.