Micro-emulsion-based dissolver for removal of mixed scale deposition

Abstract

The term mixed scale pertains to the scales found in oil and gas production system containing both organic and inorganic constituents in such a way that either aqueous-based inorganic dissolver or solvent-based organic dissolver fails to act on it. These scales are also known as wetted scales. This research discovers formulations which can effectively dissolve and disperse mixed scales dominated by inorganic content. Micro-emulsion-based solutions are identified as the best in tackling such mixed scales. A few inorganic and organic dissolving chemicals along with surfactants and co-surfactants are considered in this research to develop environment friendly solutions. The stable micro-emulsions are subjected to detailed dissolution study to establish their efficacy. The synthesized chemical solutions are shown to dissolve mixed scales of different composition. A chelant-based micro-emulsion formulation is also found to be effective in dissolving difficult to treat metal naphthenate scales co-precipitated with organic content, which is a novel application.