Laboratory Investigation of Combination of Alkali/Surfactant/Polymer Technology for Daqing EOR

Abstract

Summary Alkali/surfactant/polymer (ASP) formulas were developed for the Daqing oil field, Peoples Republic of China, with two surfactants from the U.S. (Petrostep B-100 and a blend of TRS-18 and TRS-40) and one Chinese surfactant (PS-D2). Each ASP solution gave interfacial tension (IFT) values in the range of 1 × 10−3 mN/m. Rheologic studies with polyacrylamide polymers indicate that solution viscosity decreases with alkali addition, as does the pseudoplasticity of the solution. Addition of surfactant to the alkali/polymer solution increases the solution viscosity with no slope change in the viscosity-vs.-shear-rate plot. Incremental oil recovery was higher than that with waterflood; 20% original oil in place (OOIP) for 0.2-PV ASP injection and 33% OOIP for 0.3-PV ASP injection in Daqing core. Surfactant and alkali retention were both < 1 mg/g sand. The positive results of this laboratory study provided a fluid formula for a pilot ASP flood in the Daqing oil field.