Corrosion Inhibitor Performance under High Temperature / High Salinity Sweet Conditions

Abstract It is well known that the inhibitor efficiency is encumbered by many variables, such as temperature, pressure, pH, flow speed and chemical composition of the production fluid. Salt content of formation water varies dependent on the location and sometimes exceeds more than 10%. The influence of the salinity was investigated here. The performance of several corrosion inhibitors was evaluated with an electrochemical measurement namely Liner Polarization Resistance (LPR) and weight loss coupons in autoclaves. Test solution was synthetic brines with Total Dissolved Solids (TDS) up to 17%. The test solution was aerated with CO2 at ambient temperature and pressure before testing between 60 and 100 °C. Corrosion inhibitors performed at low temperature better than high temperature condition. Some of them showed poor inhibitor efficiency in case of pre-corrosion with high salinity. Several set up with/without pre-corrosion step was done to confirm the associated impact of corrosion testing procedure on the overall performance of the corrosion inhibitors. It seems that high salinity affects the inhibitor adsorption competing with corrosion product. The pre-corrosion test is an indispensable step for a qualification of corrosion inhibitors for a high salinity field.