Study on application timing and solution performance optimisation of composite system after polymer flooding

Abstract

The appropriate application timing and application system of compound flooding can maximise the recovery after polymer flooding. Taking a polymer flooding heavy oil reservoir as an example, the application timing and solution performance of the composite system are analysed and studied, respectively. The results show that the application time of composite flooding should be at the end of the effective mobility control time of polymer flooding after the disappearance of polymer action. Increasing RRF can effectively prolong the effective flow control of polymer flooding. Among the solution properties of the composite system, the contribution of solution viscosity is relatively larger, accounting for 54.88%. After considering the effect of the complete polymer flooding control process (polymer flooding + subsequent water flooding = displacement of 0.44 PV), a composite system with a viscous system as the main component (100–200 mPa∮ s) and an appropriate interfacial tension reduction is further developed. [Received: August 7, 2020; Accepted: September 11, 2020]