Corrosion analysis of CCUS oil wells and research and application of chemical anticorrosion technology

Aiming at the serious corrosion problem of tubing strings in carbon flooding and carbon storage oil production wells in G66×1 fault block, through the analysis of corrosion products of oil well tubing strings, it is clarified that CO₂ corrosion with FeCO₃ as the main corrosion product is the main cause of wellbore corrosion. Combined with reservoir conditions, the analysis of corrosion influencing factors was carried out. Through corrosion evaluation experiments under high temperature and high pressure conditions, the corrosion laws of oil wells under different conditions such as temperature, CO₂ partial pressure, flow rate and chloride ion were clarified. According to the protection characteristics of corrosion inhibitors, a collaborative anti-corrosion technology of liquid corrosion-n inhibitor and solid corrosion inhibitor was proposed. Under oil well working conditions, through corrosion inhibitor evaluation experiments, reasonable construction parameters and filling processes were determined. The implementation of comprehensive chemical technology was carried out in Gao 66×1 fault block, which achieved a good protective effect. Corrosion monitoring data shows that the iron ion concentration in produced fluid decreased by 80% before and after gas injection, and the corrosion inhibition rate can reach more than 85%. This verifies the effectiveness of chemical anti-corrosion technology.