Displacement characteristics of worm-like micelle CO2 foam and treatment of produced liquid

Abstract

The stability of CO2 foam seriously restricts its stimulation effect in low-permeability reservoirs, and the presence of foaming agents and foam stabilizers in the system will make the production fluid treatment more difficult. Therefore, in response to the above problems, this paper prepared a CO2-responsive worm-like micelles (WLMs) using N,N-dimethyl oleoaminde-propylamine (DOAPA) and sodium salicylate (NaSaI) as raw materials, and investigated its foam performance, fluidity-control ability, oil-displacement performance, microscopic-seepage law, and microcosmic, demulsification and defoaming analysis of the simulated produced-fluid. Experimental results showed that DOAPA-H+ increased the viscosity and stability of the foam-based solution under the action of organic salt. In homogeneous and heterogeneous models, worm-like micelle CO2 foam (DOAPA@NaSaI-H+) enhance oil recovery (EOR) by 26.2% and 27.3%, respectively, which were about 1.5 times that of traditional CO2 foam. After injecting N2 into the production fluid, the system can realize rapid and pollution-free demulsification and defoaming. The research shows that DOAPA@NaSaI-H+ has great potential to EOR and reduce the difficulty of production-fluid treatment, which provides a new idea for low permeability reservoirs combined with CO2 resource utilization and storage.