Analysis of Corrosion Factors in Gas Wells of Sulige Gas Field

The composition of produced gas, water and oil from 21 sampling sites in Sulige gas field was analyzed in laboratory. The corrosion behaviors of N80 steel in the produced water of typical blocks were studied through coupon corrosion testing and electrochemical testing. The results show that Sulige gas field was gas reservoir with low concentrations of H₂S and CO₂. In the produced water with low concentration of Cl^- N80 steel had high electrochemical impedance, while in the produced water with high concentration of Cl^- the free corrosion potential of N80 steel moved to negative direction. The corrosion of N80 steel was dominated by CO₂ corrosion in upper Palaeozoic reservoir of Sulige gas field, and by H₂S corrosion in lower Palaeozoic reservoir.