High Performance Hybrid Polyorganosiloxane Cements for Enhanced Geothermal Systems

Geothermal energy technologies have the potential to provide a significant source of clean electrical energy for U.S. citizens yet face considerable technical and economic challenges to market acceptance and integration. Of particular interest, enhanced geothermal systems (EGS) have the potential to significantly increase the quantity of extractable geothermal energy from previously unusable hot dry rock (HDR) using hydraulic stimulation. It should be noted, however, this process employs demanding operational conditions that result in drastic thermomechanical stress leading to failure of conventional cement sheaths. Thus, robust cement materials capable of long term durability within demanding EGS environments represent an integral enabling technology. The proposed hybrid copolymer cement system will provide a near term solution for ongoing cement durability challenges within current EGS wellbore environments. By transitioning an established blast / ballistic protective polymeric system developed for the U.S. Navy to geothermal energy technology development, a near term displacement for current EGS cement formulations with drastically improved durability will be realized with negligible technical risk. The proposed hybrid cements will serve as an enabling technology for enhanced component lifetime within aggressive EGS well environments. The benefit of employing this technology will thus include reduced life cycle costs for EGS wellbores, extended operational environments (higher thermal tolerances and pressure thresholds) and facile reparability options within legacy EGS wells. Ultimately, the proposed hybrid polymeric cement materials will contribute to the DOE