Successful Application of a Low Dose Surfactant Injectivity-Aid in a Canadian Polymer Flood

Abstract

Abstract To achieve a successful polymer EOR application, it is crucial to maintain high polymer injectivity below the fracture pressure. This helps to prevent fracture propagation in the reservoir, which can cause fast breakthroughs, while still enabling the fastest recovery of oil. Laboratory and field testing of the addition of surfactant into a polymer injection system has shown that it can reduce the interfacial tension between injected fluids and reservoir oil, enabling more efficient oil displacement and enhanced sweep efficiency. Additionally, tailored surfactant can modify rock wettability and mitigate polymer retention in the reservoir, thereby improving polymer injectivity. In a previous paper related to this work, He et al (2024) conducted a detailed laboratory study to select an effective low dose surfactant injectivity-aid for the Atlee Buffalo field in Canada. The study comprised of fluid characterization, thermal stability, interfacial tension (IFT), emulsion tendency, polymer compatibility, and core flood performance testing. It was concluded from the laboratory core flood experimental results that the addition of a unique surfactant, at low concentrations, did indeed enhance both injectivity and oil recovery. This paper explores the results from the field pilot application of the selected surfactant from their study into an ongoing polymer flood project. Changes to the injectivity of wells moving from waterflood to polymer flood, and again from polymer flood to polymer-surfactant flood, have been assessed. Review of the initial field pilot trial data shows a positive impact of the surfactant injectivity-aid mixed within the polymer solution that was injected as part of an EOR polymer scheme. The injection data demonstrates that even at low dosage, the addition of surfactant to polymer solutions can stabilize and improve the injection process.