Corrosion Behavior of Deep Water Oil Production Tubing Material Under Supercritical CO2 Environment: Part 1—Effect of Pressure and Temperature

• Published in: Corrosion (Houston, Tex.) Tex.), 2014, Vol.70 (1), p.38-47
• Main Authors: CHOI, Yoon-Seok, FARELAS, Fernando, NESIC, Srdjan, MAGALHAES, Alvaro Augusto O, DE AZEVEDO ANDRADE, Cynthia
• Format: Article
• Language: English
• Subjects: Analytical methods; Applied sciences; Brines; Carbon dioxide; Carbon steel; Carbon steels; Carbonates; Cementite; Corrosion; Corrosion environments; Corrosion potential; Corrosion products; Corrosion rate; Corrosion tests; Crude oil; Deep water; Electrochemical impedance spectroscopy; Electrochemistry; Electrode polarization; Electrodes; Electron microscopy; Environmental effects; Evaluation; Exact sciences and technology; Iron; Iron carbides; Iron carbonate; Linear polarization; Materials selection; Metals. Metallurgy; Microscopy; Oil production; Partial pressure; Petroleum production; Pressure; Pressure effects; Saline water; Scanning electron microscopy; Sodium; Sodium chloride; Spectrum analysis; Temperature; Tubing; X rays; X-ray diffraction; X-ray spectroscopy
• ISSN: 0010-9312; 1938-159X
• DOI: 10.5006/1019

The objective of the present study was to evaluate the corrosion properties of carbon steel in supercritical carbon dioxide (CO2/brine mixtures related to the deep water oil production development. Corrosion tests were performed in 25 wt% sodium chloride (NaCl) solution under different CO2 partial pressures (4, 8, 12 MPa) and temperatures (65 degree C, 90 degree C). Corrosion behavior of carbon steel was evaluated using electrochemical methods (linear polarization resistance [LPR] and electrochemical impedance spectroscopy [EIS]), weight-loss measurements, and surface analytical techniques (scanning electron microscopy [SEM), energy-dispersive x-ray spectroscopy [EDS], x-ray diffraction [XRD], and infinite focus microscopy [IFM]). The corrosion rates measured at 65 degree C showed a high corrosion rate (10 mm/y) and a slight difference with pressure. Under these conditions, the sample surface was locally covered by iron carbide (Fe sub(3) not equal to ), which is porous and non-protective. However, the corrosion rates measured at 90 degree C increased with time at the initial period of the test and decreased to a very low value (0.05 mm/y) due to the formation of protective iron carbonate (FeCO sub(3)) layer regardless the CO2 partial pressure.