Comparative study of VOF, LS, and VOSET on pore-scale immiscible waterflooding modeling

Abstract

The pore-scale mechanism of the waterflooding contributes to enhancing oil recovery, which has been widely emphasized in the petroleum industry. In this paper, the performances and accuracy of three tracking interface algorithms, including VOF, LS, and VOSET, are compared and analyzed through two-phase flow in the conceptual model of pore-throat. The results show that the VOSET method combines the advantages of the other two methods, which not only satisfies the mass conservation but also improves the continuity of the physical quantities near the interface. Then, based on the binary image of the pore, the two-dimensional micro pore model is reconstructed by extracting image contour. The grid independence of the reconstructed pore model is verified by the single-phase flow simulation. The waterflooding process in the reconstructed pore model is simulated using the VOSET method, and the effects of displacement speed and wettability on the oil recovery are analyzed. The morphologies of residual oil under different conditions of wettability are investigated and analyzed. The study provides a basic theory for modeling the pore-scale oil-water flow and optimizing the scheme of the water injection.

Keywords

• Waterflooding
• Oil recovery
• VOSET
• Displacement speed
• Wettability