Sulfate-reducing bacteria corrosion at 60 °C in the CO2-saturated artificially tight gas produced water containing condensate oil.

In the gas field, steel corrosion issues induced by sulfate-reducing bacteria (SRB) are a crucial factor in pipeline service failure. The effect of condensate oil on SRB corrosion in CO2-containing gas field environments at high temperatures remains unknown. In this work, the inhibition behavior of SRB corrosion at 60 °C induced by condensate oil in the CO2-saturated artificially tight gas produced water was investigated in-depth. The experimental results indicated that SRB can maintain a certain level of bioactivity in the test solution at 60 °C, although the cell concentrations appear to decrease. The uniform and localized corrosion of steel in the CO2-saturated solution containing SRB shows an acceleration, but the addition of condensate oil mitigates it. In the environments containing SRB, the density of corrosion pits with a value of (5.56 ± 0.38) × 102 pits·cm-2 and the corresponding maximum localized corrosion rate of (0.143 ± 0.018) mm/y are found, but these values decrease to (3.78 ± 0.38) × 102 pits·cm-2 and (0.091 ± 0.018) mm/y after the addition of condensate oil. A new insight into the understanding of steel corrosion in the gas condensate reservoirs containing CO2, condensate oil, and SRB at high temperatures is presented in this study.