The Gre Geo Project – Development of Corrosion-Resistant Casing Systems

The key challenges currently encountered in the geothermal industry are corrosion and scaling. They significantly reduce the lifespan of the steel casing systems, causing wellbore integrity issues, which could lead to major environmental contamination. Moreover, the corrosion leads to surface degradation of the casing, causing excessive pressure losses. To prevent major damage, costly workover operations are inevitable, becoming a substantial financial burden and may ultimately jeopardize project economics.

The GEOTHERMICA-funded GRE-GEO project rallies a multinational consortium of geothermal experts to solve these challenges through development of the new glass fiber reinforced epoxy casing system for geothermal applications.

In contrast to conventional systems, Glass Fiber Reinforced Epoxy (GRE) casings provide a much-desired alternative, as this material is corrosion resistant. GRE tubulars are already used in highly corrosive oil wells; however, the small inner diameters and large outer diameters of GRE pipes and connector systems significantly limits their application in geothermal wells.

GRE GEO is developing an improved GRE casing system, large enough to be installed in geothermal wells without causing relevant pressure drops. The new system is being designed for completion of new geothermal wells and will also be suitable for workover and modernization of old ones. As a result, retrofitted wells may not only gain improved corrosion resistance but also an improved production index, improving the profitability even further.

Additionally, the project is undertaking the establishment of necessary standards & guidelines, adjustment of the well design, as well as preparation of the qualification and safe installation procedures of the GRE casing system. Supplementary, a set of optimized handling tools will be proposed and completed with the optimization of a handling for running GRE casing and tubing.

To abide well integrity standards and all safety regulations, the development of a new API- and ISO-aligned GRE-standard for casings will be conducted in parallel with the development of the casing system. During the testing phase of the project, the designed pipes are sent through a variety of verification procedures to re-create real subsurface conditions and monitor GRE-pipe performance. The testing program includes short-term and long-term examination. The project will be finalized with the construction of one or more GRE-cased wells to prove the viability of Glass Fiber Reinforced Epoxy casing systems for geothermal wells.

GRE-GEO promises a corrosion-resistant alternative to conventional steel casings, enabling a decrease in operational risks and cost, at the same time improving the lifespan and long-term flow properties in geothermal energy projects.