High Temperature Seismic Monitoring for Enhanced Geothermal Systems - Implementing a Control Feedback Loop to a Prototype Tool by Sandia National Laboratories

Geothermal energy can make an important contribution to the U.S. energy portfolio. Production areas require seismic monitoring tools to develop and monitor production capability. This paper describes modifications made to a prototypical seismic tool to implement improvements that were identified during previous tool applications. These modifications included changing the motor required for mechanical coupling the tool to a bore-hole wall. Additionally, development of a closed-loop process control utilized feedback from the contact force between the coupling arm and bore-hole wall. Employing a feedback circuit automates the tool deployment/anchoring process and reduces reliance on the operator at the surface. The tool components were tested under high temperatures and an integrated system tool test demonstrated successful tool operations.