A simulation study on hydrogel performance for enhanced oil recovery using phase-field method

Hydrogels are increasingly applied in oil recovery processes. This leads to more controlled flow of fluids in porous media. In this process, hydrogel is injected to the reservoir to block the high permeability areas. The trapped oil in low permeability regions, is then swept by water flooding. pH-sensitive hydrogel microspheres were synthesized in another work of the authors, which effectively increased the oil recovery factor in experimental studies. In this communication, phase-field approach was used to simulate this process and to obtain the tuning parameters of the model including thickness of the contact surface (epsilon), phase transform parameter (M-0), and excess free energy (perpendicular to). Diffusion of hydrogels was studied by Cahn-Hilliard conservative approach and the breakage, deformation, and plugging mechanisms were analyzed, based on pressure drop variations in micromodel. Moreover, Effective parameters on oil recovery factor were analyzed. Results indicated a good agreement between experimental and modeling studies of oil recovery factor in water and hydrogel flooding with absolute errors of 2.29% and 4.06%, respectively. The recovery factor was calculated using a statistical method which was in good agreement with the modeling results. The tuned parameters of the model were reported as, epsilon = 111.7 mu m, M-0 = 5 x 10(-13) m(3)/s, perpendicular to=-0.0003 J/m(3).

Automated summary

Hydrogels are increasingly used in oil recovery processes to control fluid flow in porous media. The authors synthesized pH-sensitive hydrogel microspheres, which effectively increased the oil recovery factor in experiments. In this study, a phase-field approach was used to simulate the process and obtain the model's tuning parameters. The diffusion of hydrogels and the mechanisms of breakage, deformation, and plugging were analyzed. The results showed good agreement between experimental and modeling studies, with absolute errors of 2.29% and 4.06% for water and hydrogel flooding, respectively. The tuned parameters of the model were reported.