Alteration of Sand Wettability by Corrosion Inhibitors and Its Effect on Formation of Sand Deposits

Abstract

Abstract The surface chemical properties of solids particles strongly influence their behavior in multiphase flow, e.g. their tendency to be transported by the oil or water phase, or stick to the oil-water interfaces, or their tendency to aggregate. The behavior of the solid particles may influence various phenomena such as emulsion stability, oil-water separation, sedimentation of solids in a pipeline, corrosion under deposits, and erosion. The present paper focuses on the behavior of quartz sand in a simple oil-water system in presence of a model corrosion inhibitor compound; cetyltrimethylammonium bromide (CTAB). Refined, low-aromatic oil was used in the tests. Zeta-potential measurements on crushed sand particles demonstrated that CTAB adsorbed onto the sand particles. Wettability of the sand surface was measured by capillary rise velocity of water and oil in sand columns. Adsorption of the model corrosion inhibitor changed the sand surface from preferentially water wetting to intermediate wetting. Flow behavior of the sand was studied in stirred beakers with brine, oil and sand. Addition of corrosion inhibitor caused the sand to stick to the oil-water interface. Furthermore, the sand grains aggregated to form sticky deposits that contained hydrocarbon phase. The results demonstrate the effect of surfactants on the formation of deposits, and shows that surface-active chemicals like corrosion inhibitor may significantly affect the behavior of sand in multiphase flow. These findings are important with respect to testing procedures where solids are involved. Such chemicals should thus be included in studies of solids behavior in multiphase flow. The results may furthermore contribute to improved understanding of under-deposit corrosion.