A study of the pore-blocking ability and formation damage characteristics of oil-based colloidal gas aphron drilling fluids

Effective pore blocking ability of CGA fluid was confirmed by ever increasing resistance to the injection of CGA fluid through the porous media (i.e., continuous increase of pressure drop across the porous media). Results confirmed that microbubble buildup has occurred in the porous media, which limits the fluid invasion. The permeability alteration, measured as an indication of the formation damage due to CGA fluid flow, was found to be variable.