Wellbore corrosion and failure assessment for CO2 EOR and storage: Two case studies in the Weyburn field

Abstract

Many depleted oil and gas reservoirs are targets for CO2 enhanced oil recovery, resulting in CO2 storage as part of the commercial enhanced oil recovery process. These oil fields have legacy wellbores that may contain a leakage pathway. Corrosion or degradation can occur anywhere along the wellbore through or along the cement, casing, tubing, or plugs and is a challenging issue facing the oil and gas industry. Two case studies presented here evaluate legacy wells in the Weyburn oil field. One well has injected over 263 million cubic meters of CO2, and the second well has not been exposed to CO2. These case studies aim to help understand casing corrosion in CO2-rich environments.Both wellbores exhibited signs of corrosion, with corrosion ranging from small pits to complete penetration through the casing. Contributing factors to corrosion in these wells range from exposure to injected fluids, injected CO2, packer placements, formation fluid exposure, and the corrosive environment that is present in the perforated area of the well.