A water-soluble oil-displacing agent with tracer properties for enhancing oil recovery

Abstract

A water-soluble fluorescent oil-displacing agent was prepared via copolymerization of acrylamide (AM), acrylic acid (AA) and coumarin derivatives (CO) for the first time. The rigid coumarin unit can be not only used as a fluorescent group for tracers, but also improves the heat-resistant performance of the displacement agent. The copolymer was fully characterized using FTIR, ¹H NMR, TG-DSC, UV-Vis and fluorescence measurements. The fluorescence intensity of the polymer exhibited a good linear relationship with its concentration and the linear correlation coefficient reached 0.9980, which indicated that the copolymer’s concentration can be directly determined by measuring the fluorescence intensity. The pH and brine concentration of systems have no significant effect on the fluorescence intensity of the PAAC. It was also found that the viscosity retention rate of PAAC reached up to 42.3% at 100 °C and PAAC exhibited excellent shear-thickening. Furthermore, up to 13.4% enhanced oil recovery was obtained using 2 g L⁻¹ PAAC solution according to core flood tests. All results have demonstrated that the tracer copolymer PAAC with fluorescence properties exhibits great potential application for enhancing oil recovery.