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Abstract

The effecs of HCO_3~-concentration on CO_(2) corrosion in gas and oil fields were investigated by carrying out potentiodynamic scans and weight loss tests.Potentiodynamic polarization curves showed that the cathodic current density decreased with cm increase of HCO_3~-concentration when [HCO_3~-] was lower than 0.042(mol/L.)The cathodic reations were promoted by increasing [HCO_3~-] when it reached 0.126 mol/L,(Anodic) behavior was an active process at low er [HCO_3~-] concentration and the anodic current density decreased with the increase of [HCO_3~-] concentration.An evident active-passive behavior exhibited in anodic process at 0.126 mol/L HCO_3~-.Under high pressure and high temperature,the corrosion rate of steel X65 decreased with the increase of HCO_3~-concentration while pH increased.SEM,EDS,XRD results of the corrosion scales indicated that a typical FeCO_(3) crystallite was found at low HCO_3~-concentration but Ca(Fe,Mg)(CO_(3))_(2) at high HCO_3~-concentration.Ca~(2+),Mg~(2+) precipitated prior to Fe~(2+) at high pH value.

Keywords

Oil and gas fields, CO_(2) corrosion, HCO_3~-concentration

Publication Date

2005-11-28

Online Available Date

2005-11-28

Revised Date

2005-11-28

Received Date

2005-11-28

References

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