Breakup and coalescence mechanism of high-stability bubbles reinforced by dispersed particle gel particles in the pore-throat micromodel

Abstract

Bubble breaks up and coalesces continuously during migration in reservoirs, which determines the size distribution of bubbles. As a key parameter of foam technology, the bubble size greatly affects foam stability and plugging performance in the reservoir. Aiming to solve the problem of poor stability of ordinary foam under reservoir conditions, in this study, a high-stability foam for profile control was prepared using dispersed particle gel particles as a foam stabilizer. The characteristics of foam were mainly investigated by the modified Ross-Miles method and microfluidic experiments. The obtained results showed that the foam reinforced by dispersed particle gel particles had a longer half-life under reservoir conditions. It is easier to break up from parent bubbles to daughter bubbles during the migration, which can form foam with higher stability in the porous media. The average size of the daughter bubbles decreased with increasing liquid-phase flow rate, pore-throat ratio and capillary number. The average size varied with the capillary number in a power-law form. Because of the viscoelastic interfacial film and liquid-phase viscous network, the shear effect on the parent bubble in reinforced foam was increased when passing through the pore-throat structure with variable diameter. The large parent bubbles were more likely to break up into more small and stable daughter bubbles. And the interfacial film with higher mechanical strength makes it difficult for the daughter bubbles in reinforced foam to coalesce again. The results indicated that the reinforced foam had stronger dynamic stability and better plugging performance in the reservoir. This work revealed the breakup and coalescence mechanism of bubbles reinforced by dispersed particle gel particles in porous media and provided theoretical guidance for the application of foam technology in high water-cut reservoirs.