Corrosion main control factors and corrosion degree prediction charts in H2S and CO2 coexisting associated gas pipelines

The pipeline corrosive environment in T oil field contains H2S and CO2, with 96 corrosion perforations. OLGA software was used to simulate the internal flow environment. Combined with Pearson correlation coefficient analysis method and the Apriori algorithm, the association rules between corrosion rate and main corrosion control factors were determined. The results show that corrosion perforation of associated gas pipelines mostly occurred at the effusion in low-lying and climbing sections. Corrosion in the associated gas pipelines were strongly related to liquid velocity and holdup, and moderately related to temperature, H2S partial pressure and CO2 partial pressure. 10 association rules with confidence ≥90% between main corrosion control factors and corrosion rate were mined. Finally, the three kinds of corrosion evaluation charts parameters: liquid velocity & holdup, temperature & PCO2/PH2S and liquid velocity & PCO2/PH2S were established respectively.