Pitting Corrosion and Microstructure of J55 Carbon Steel Exposed to CO2/Crude Oil/Brine Solution under 2–15 MPa at 30–80 °C

Abstract

This study aimed to evaluate the corrosion properties of J55 carbon steel immersed in CO2/crude oil/brine mixtures present in the wellbores of CO2-flooded production wells. The main corroded position of wellbore was determined and wellbore corrosion law was provided. Corrosion tests were performed in 30% crude oil/brine solution under the simulated temperature (30–80 °C) and pressure (2–15 MPa) conditions of different well depths (0–1500 m). The corrosion behavior of J55 carbon steel was evaluated through weight-loss measurements and surface analytical techniques, including scanning electron microscopy, energy dispersive spectrometer, X-ray diffraction analysis, and optical digital microscopy. Corrosion rate initially increased and then decreased with increasing well depth, which reached the maximum value of 1050 m. At this well depth, pressure and temperature reached 11 MPa and 65 °C, respectively. Under these conditions, FeCO3 and CaCO3 localized on sample surfaces. Microscopy was performed to investigate corrosion depth distribution on the surfaces of the samples.

Effect of CO2 Partial Pressure on the Corrosion Inhibition of N80 Carbon Steel by Gum Arabic in a CO2-Water Saline Environment for Shale Oil and Gas Industry

“…At higher pH, the concentration of H + ions in the solution is smaller, which would result in the formation of fewer protonated inhibitor molecules available for the absorption process. Another possible reason may be due to the fact that these types of inhibitors get absorbed via electrostatic interactions (e.g., van der Waal forces) onto the surface of the metal, and it is known that this types of interaction generally grow weaker with an increase in temperature due to larger thermal motion [ 3 , 20 ]. Consequently, an increase in temperature will increase the metal surface kinetic energy, which has a detrimental effect on the adsorption process and encourages desorption processes [ 15 , 20 ].…”

“…The high corrosion rate observed at higher CO2 partial pressures can be explained with the increase of the acidity of the solution. In fact, in the presence of CO2, the weak carbonic acid is formed, which in turn dissociates in HCO 3 and in CO 3 -, according to the following reactions: The solubility of CO 2 in water increases sharply with increasing the pressure of the system [31]. The high corrosion rate observed at higher CO 2 partial pressures can be explained with the increase of the acidity of the solution.…”

“…However, after years of exploitation, the oil and gas production in the reservoir declines to result in a major economic challenge for the oil companies. The injection of CO 2 at high pressure into the wellbore is an effective method to increase the oil fields lifetime [ 1 , 2 , 3 , 4 ]. This process is usually referred to as carbon dioxide flooding enhanced oil recovery (CO 2 -EOR).…”

Effect of Temperature on Corrosion Behavior and Mechanism of S135 and G105 Steels in CO2/H2S Coexisting System

“…The corrosion products generated at 100 • C were mainly FeCO 3 and FeS and the amount of FeCO 3 with loose porous corrosion product was greater. FeCO 3 is a loose and porous corrosion product [22,23]; therefore, the substrate material at this temperature was more susceptible to corrosion. Figure 6 presents SEM cross-section images of the corrosion products of the S135 and G105 at different temperatures.…”