Flow Loop Study of NaCl Concentration Effect on Erosion, Corrosion, and Erosion-Corrosion of Carbon Steel in CO₂-Saturated Systems

Abstract

Erosion-corrosion deterioration of carbon steel in carbon dioxide (CO 2 )-saturated systems with sand is a problem in the oil and gas industry because the combined effects of erosion and corrosion can reduce the protection provided by iron-carbonate scale formation or inhibitors. Oil and gas production can be accompanied by the formation water (typically chloride containing brine). Some effects of chloride concentration on corrosion are not widely known, and this can result in misleading conclusions. The goal of this paper was to contribute to a better understanding of the effects of chloride concentration in CO 2 corrosion. Previous studies reported in the literature and experimental and theoretical studies conducted in the present work have shown that increasing the sodium chloride (NaCl) concentration in solution has three important effects on corrosion results. First, standard pH meter readings in high NaCl concentration solutions require corrections. Second, increasing the NaCl concentration decreases the CO 2 concentration in solution and therefore contributes to a decrease in the corrosion rate. Third, increasing the NaCl concentration increases the solubility of FeCO 3 and therefore reduces the likelihood of forming an iron carbonate scale. High NaCl concentration also decreases the sand erosion rate of the metal slightly by increasing the density and viscosity of the liquid.

CO2 Corrosion in the Region Between the Static and Turbulent Flow Regimes

“…There is a wide variety of models for understanding the CO 2 corrosion of carbon steel 2,3,4,5,6,7 . It is known that the CO 2 effect is associated with the increased amount of hydrogen developed in the cathode and with the formation of an iron carbonate film as a corrosion product on the steel surface.…”

Predictive Modelling of Wellhead Corrosion due to Operating Conditions: A Field Data Approach

“…Other factors that could have an impact on wellhead corrosion rate are organic and inorganic acids, bacteria, turbulence, erosion, erosion-corrosion, bubbles formation, and condensation resulting from the flow of the oil and gas [18,32,[34][35][36][37]. The predicted corrosion model was validated with field data, experimental results, and de Waard-Milliams corrosion models.…”

“…The most important parameters that can enhance the result of corrosion prediction are those related to the steel properties, water chemistry, flow pattern, oil-versus-water wetting, and operating conditions [20]. This is why the works of numerous authors focused on them [7,8,10,11,15,[19][20][21][22].…”

“…Their works have focused on knowing the contribution of different operating parameters in the oil and gas such as CO 2 , H 2 S, temperature, bacteria, and so forth on the entire corrosion process. Others investigated the impact of the mechanical process of fluid flow and associated effects of turbulence on corrosion of pipelines, well tubing, vessels, tanks, and so forth [17][18][19]. Despite the enormity of the work on corrosion, it is difficult to summarily prescribe a holistic solution to the corrosion process.…”

Design of an elbow for integrated gravimetric, electrochemical and acoustic emission measurements in erosion-corrosion pipe flow environments

“…Direct impingement test cells, contained within flow loops, have also been used to study mechanisms of erosion-corrosion in various experimental conditions relevant to the oil and gas industry [32][33][34][35][36]. The test cell was used to investigate erosion-corrosion multiphase flow conditions [32], to assess corrosion inhibitor performance in sand-containing environments [33], to assess the significance of sand particle impingement on the integrity of corrosion products [34,35] and to assess the influence of high sodium chloride (NaCl) concentrations on erosion-corrosion of carbon steel [36]. Samples were positioned opposite to a nozzle, similarly to SIJ tests, but the apparatus was capable of being used for much higher flow velocities, up to 60 m/s [33].…”