The long-term service life outcomes were compared for similar natural gas storage wells operated with either no cathodic protection or partial cathodic protection. Cathodic protection for storage wells is not mandated by regulation and industry practice varies so the outcomes for more than 350 wells were assessed based on casing inspection logs, historical failure rates and service lives. Casing inspection logs indicated a higher prevalence of external corrosion on the wells without cathodic protection. Furthermore, of the wells that had been remediated/abandoned, those operated with partial cathodic protection were found to have increased service lives when compared with the wells operated without cathodic protection. A higher percentage of the wells operated without cathodic protection also required remediation/abandonment. Overall, the data supported a conclusion that partial cathodic protection lead to improved service life outcomes and reduced external corrosion.
This case study uniquely allows the comparison between long-term service lives for similar storage wells operated without cathodic protection and those with partial cathodic protection.
