5. Corrosion resistant alloy experience

Experience from the above LE geothermal reservoirs shows that most European operators are using low alloy steel casing (e.g., L80) for completing their wells. Where corrosion rates have been found to be excessive, either corrosion inhibition or organic coatings have been applied to successfully mitigate corrosion and scaling issues.

Corrosion resistant alloys (CRAs) starting with 13 % chromium (martensitic stainless steels) can also be used to control CO ₂ corrosion, however geothermal operators have noted that the high levels of chlorides found in some geothermal formation waters has led to pitting of these materials. If H ₂ S is present, 13 % Cr stainless steels are subject to stress corrosion cracking.

Work carried out in high salinity (> 200,000 mg/l...