Kinetic Parameters of Pitting Corrosion Process in Oilfield Pipeline Materials
نویسندگان
1 Department of Materials Science and Technology of Art Products, Saint Petersburg, Mining University, Russian Federation
2 Department of Materials Science and Technology of Art Products, Saint Petersburg, Mining University, Russian Federation
3 Department of Materials Science and Technology of Art Products, Saint Petersburg, Mining University, Russian Federation
doi
10.5829/ije.2026.39.11b.23چکیده
The issue of corrosion pits formation on the inner surface of oilfield pipelines remains insufficiently studied. Based on the premise that the destruction of oilfield pipeline pipes due to pitting corrosion requires the simultaneous fulfillment of such conditions as the presence of chloride ions in the water-oil emulsion, the enrichment of the emulsion with oxygen, the stressed state of the pipe metal, and the periodic removal of corrosion products due to the abrasive action of solid particles, a methodology for testing pipe steels for resistance to pitting corrosion has been proposed. During the experiment, the authors established the kinetic parameters for 4 grades of pipe steel and concluded that the values of k₀ and kt (the pitting corrosion rate in a stress-free state and at a given stress level σt, respectively) at σt = 0.7σY for low-alloy steel 09G2S (k0 = 2.37 and k₀.₇σY = 10.51 mm/year) are significantly lower than the values of similar parameters for carbon steels St3, 08ps, 20kp (k₀ = 3.33 ÷ 4.12 mm/year, k₀.₇σY = 12.00 ÷ 14.45 mm/year). The mechanochemical coefficients kσ of pitting corrosion of the specified steels were also determined, and it turned out that they also differ (up to 1.5 times): Kσ = 0.039 mm/(year·MPa) for steel 09G2S compared to Kσ = (0.045 ÷ 0.059) mm/(year·MPa) for carbon steels. The established pitting corrosion rates proved to be close to those observed in the practical operation of oilfield pipelines.
