Improve the tribo-corrosion behavior of oil-in-water emulsion-based drilling fluids by new derivatives of fatty acid-based green inhibitors

Drilling fluids are essential for oil-field drilling operations, which generate lubricating films to minimize direct contact between moving metal parts and surroundings for reduced friction, corrosion and wear. Various additives are added to drilling fluids to meet the needs. However, traditional additives contain environmentally unfriendly substances, e.g., sulfur and phosphorus. In this study, we investigated effects of three new green corrosion inhibitors, PEG-2 oleamide, Glycerol myristate, and Glycerol linoleate, on tribo-corrosion of carbon steel. Worn surface and lubricating films formed on steel surfaces were analyzed. It is demonstrated that the emulsion-based fluids were significantly improved by the green inhibitors, evidenced by significant reductions in corrosion, COF and wear. Mechanical properties and adsorption abilities of the inhibitor-produced films were also investigated through atomistic simulations.