Corrosion behavior of low-alloy steel in the presence of Desulfovibrio caledoniensis

Sulfate-reducing bacteria (SRB) are shown to be common inhabitants of oil reservoirs. Desulfovibrio caledoniensis isolated from a production well was used in this study. After an incubation period of 1 month with the SRB culture, two layers of corrosion products with different compositions were detected on the test coupons. The Tafel plots showed that the corrosion potential exhibited a cathodic shift and the corrosion rates increased with the incubation time. The analysis of the Nyquist diagrams revealed that the diffusion process begins to dominate with time in bacteria containing medium. These results are in good accordance with the Tafel data.