Geothermal wells are usually operated under high-temperature high-pressure (HTHP) conditions with 100-1000 meters depth. Short life span of steel casing (< 2 years) is very often encountered due to increasing corrosiveness as well fluid chemistry changes during operation. This results in high operation cost and production time loss due to the need to replace well casing materials. Use of Corrosion Resistance Alloys (CRA) becomes necessary for some challenging well conditions e.g. low pH, high CO2/H2S/HCl content and long well life. However, there is lack of established guideline for systematic material selection and qualification specifically for geothermal application. Selection of CRAs is often based on limited literature data or empirical testing case by case, which is time consuming, costly, and often results in an over-conservative solution.
- Conduct state-of-the-art materials and geothermal well condition review
- Propose and conduct comprehensive laboratory testing to evaluate the performance of a range of applicable materials in typical geothermal well conditions
- Develop a material selection and qualification guideline for geothermal well casing materials
- Propose the development of a Recommended Practice (RP) for selection and qualification of geothermal well casing materials.
- Provide industry recognized materials selection guidelines for geothermal well
- JIP consortium gains exclusive access to the project results for a lock-in period of at least 3 years
- Enable cost-effective materials solutions without the need to qualify materials case by case and so save operation time and reduce cost
- Reduce operational risk associated with corrosion failure.
Cost of CRA can exceed 5-10 times that of carbon steel. The nominal capital investment needed to use CRA casing materials is approximately USD 100-500K per well depending on the size of casing, depth of well and grade of materials selected. A cost saving of 20–50% can be achieved with the safe use of more realistic materials solution. In a field of 10 wells, this can translate to savings of up to USD 1 million.