A Study of the Effects of Colloidal Gas Aphron Composition on Pore Blocking

Abstract

Summary Drilling fluid containing colloidal gas aphron (CGA) microbubbles can bridge the pores of the reservoir rock in the near-wellbore region and reduce the risks of lost circulation and formation damage. The advantage of using CGA systems is that the CGAs can be removed easily during the initial stages of production, thereby reducing the costs associated with stimulation processes such as acidizing. Although there has been some work performed on the flow of the microbubbles through porous media, little is known about the optimal conditions for blocking the pores. Specifically, the effect of the interaction between microbubbles and reservoir fluid on the microbubble stability and pore-blocking ability has not been determined. This study is focused on determining effects of CGA composition on the resistance to the flow of microbubbles through porous media. Increasing resistance to fluid flow was observed as more CGA fluid was injected, indicating that microbubbles could effectively block the pores. Effects of water, brine, mineral oil, and crude oil, as saturating fluids, on the microbubble stability and pore-blocking ability were also investigated.