Carbon dioxide corrosion of oil and gas field equipment

Abstract

Conditions for carbon dioxide corrosion in oil, gas, and gas-condensate fields are discussed. Corrosion mechanisms in oil, gas, and gas-condensate fields and gas and oil pipelines are compared. Various factors are shown to affect the CO 2 corrosion rate of steel in oil and gas field media.

A study of X100 pipeline steel passivation in mildly alkaline bicarbonate solutions using electrochemical impedance spectroscopy under potentiodynamic conditions and Mott–Schottky

“…− ] at any fixed temperature increases alkalinity in the H 2 CO 3 equilibria relations, and FeCO 3 formation is generally accelerated with both increased alkalinity and [HCO 3 − ] as described in [18]. Minimal Fe(OH) 2 involvement in the formed passive layer is likely due to thermodynamic unviability at the polarization potential 0.5 V SCE .…”

“…3, slight positive inflections in the Nyquist profile at 1 Hz are the result minor impedance increases from a frequency dependent surface process on the otherwise bare steel. At this potential, well before the significant current density retardations above E p1 , adsorption of pre-passive ferrous bicarbonates ([FeHCO 3 − ] ads and [FeHCO 3 ] ads , [18]) occurs prior to formation of FeCO 3 . In addition, the adsorption of ferrous hydroxide (FeOH ads ) is a necessary prerequisite to the development of Fe(OH) 2 as shown by Castro and Vilche [19].…”

Dual functions of chloride ions on corrosion behavior of mild steel in CO2 saturated aqueous solutions

“…For Cl − ions free CO 2 saturated solutions, the formation of some absorbed complexes, such as [FeHCO 3 − ] ad and [FeHCO 3 + ] ad might occur at the metal surface as follows: …”

Modeling Corrosion Reactions of Steel in a Dilute Carbonate Solution

“…The produced hydroxyl ions together with the hydroxyl ions from the solution get involved with the first adsorptiondissolution steps ( Ref 23,24), as explained in section 3.2 and as shown in Eq 3 and 5a to 5c. The mechanisms of hydrogen generation, during when the adsorbed hydrogen atoms interact and generate hydrogen bubbles, could be different from commonly reported mechanisms in lower-pH CO 2 -saturated solutions ( Ref 25,26).…”