In geothermal energy, a huge potential lies in hydrothermal reservoirs close to magma where ultra-high temperature (HT) fluid (400-500 Celcius) can be harnessed to multiply the power production output. This is where Equinor is involved in different research and development projects. However, the operation conditions of these super HT reservoirs pose a tough challenge to casing systems construction, which needs to be properly designed to protect the integrity of the geothermal well during its service lifetime. There currently exist no commonly accepted design tools nor standards regulating the casing system design under such conditions. In order to solve the common challenges related to the well design end hence enabling high enthalpy (>2900kJ/kg) hydrothermal power production, HotCaSe project was initiated by Equinor and backed up by Research Council of Norway and international industry & research partners. For success, Equinor relies on partnership and cooperation with leaders in geothermal industry. However, their competence from oil & gas industry will provide a competitive leverage.
In 2021, HotCaSe has completed its four-year journey with motivated and dedicated partners. Significant R&D achievements have been achieved through both physical testing and numerical simulations. Especially, a tailored-made numerical design tool, Casinteg, was developed to evaluate and identify the most viable well construction solutions for super-hot geothermal wells. The final tool version was released, synthesising developed knowledges in the project. Casinteg is one of the most important project outcomes, not only for Equinor but also for geothermal community. During the last year of HotCaSe, work was carried out to support robust design for IDDP-3 well, which is planned by the project partner Reykjavik Energy (OR) in the years to come. Casinteg, together with experimental testing of casing and cements in relevant environments, was used provide a better understanding of mechanisms impacting the well integrity and maximise the probability of successful IDDP-3 well. In addition, the project partner ISOR has recently completed the large-scale tests of flexible couplings in the concurrent Geothermica-GeoConnect project, confirming its design basic principle for mitigating thermal stresses of casing. Experiences and knowledges achieved in the joint projects have lifted partners steps forward, closer to the possibility to harness energy from superhot geothermal wells. Developed knowledge and tool will also be transferred to secure robust wells for CO2 underground storage (IPN INTOWELL project) and further collaboration opportunities with the project partners.
This project shall develop and evaluate innovative concepts for a cost-efficient and robust casing system for geothermal wells operating at supercritical water conditions. The project will explore combinations of cements and steels, herein coating and liner technologies that modify functional and mechanical performance of the casing system. The project will further innovate design strategies and establish validated numerical and analytical design tools for such systems.