Ruggedized acoustic logging tool for wellbore integrity monitoring under extreme geothermal conditions

Enhanced Geothermal Systems (EGS) is a method under development for extracting energy from hot dry rock in the Earth’s crust without tapping conventional hydrothermal resources. Efforts are moving forward to increase technology readiness in many areas, including wellbore casing and cementing. Downhole conditions are extreme and affect the well’s casing as well as tools and sensors for casing integrity monitoring—an essential part in social license, plant operation, and life cycle costs. Our current work is developing an acoustic tool that can withstand this challenging environment. Temperatures and pressures up to 250 °C and 15 000 psi rule out the use of typical transducer materials as well as many electronics, mechanical fittings, and common engineering materials. In our presentation, we will give a broad overview of EGS and outline our goals. We will convey our approach with respect to material selection, design choices, and experimental efforts including benchmark acoustic testing at elevated temperatures and pressures. Ultimately, this challenging endeavor is to boost the viability of EGS technology and additionally establishes innovative approaches to nondestructive acoustic sensing in challenging environments.