Water produced during the production of oil and gas causes major corrosion problems in oilfield operations. The corrosivity of the produced water increases or decreases depending on the nature of the dissolved substances. Dissolved bicarbonates in produced water are found to decrease corrosion whereas the organic acids and acid gases enhance the corrosion of carbon steel in the oilfields. The mitigation of CO2 corrosion in the presence of acetic acid was investigated in this study. Rotating cylinder electrode tests were conducted to study the inhibition properties of several corrosion inhibitors. Based on the laboratory test results, watersoluble cationic organic corrosion inhibitors found to be very effective in controlling acetate enhanced CO2 corrosion.
Problems related to corrosion are encountered in oil and gas production environments during all phases of operations from upstream to downstream. The corrosivity of the production environments varies depending on the types of fluids produced, water chemistry, pH, dissolved CO2 and H2S acid gases, temperature, pressure and flow rates. The nature of the substances dissolved in the produced water determines its corrosivity. The dissolved bicarbonates in produced water were found to decrease corrosion. On the other hand, the presence of acid gases and organic acids in produced water was found to enhance the corrosion of carbon steel considerably.
Oilfield operations employ a corrosion inhibition program in a given field based on the severity of the corrosion problem in that particular field and economics. A common technique utilized for the mitigation of corrosion of carbon steel is the application of corrosion inhibitors.4-9 Organic corrosion inhibitors are found to control oilfield corrosion problems successfully. The effectiveness of conventional water soluble organic corrosion inhibitors in controlling CO2 corrosion in the presence of acetic acid (HAc) was investigated in this study. Corrosion inhibitors with three types of chemistries were selected for the study. These included an imidazoline acetate salt, a quaternary ammonium salt, and a phosphate ester. The inhibition properties of the chemicals were evaluated using electrochemical polarization resistance10-13 data.