Rugged, Long-Life Flow Monitoring for Enhanced Geothermal Systems

Access to the earth’s subsurface requires technologies that can operate at extremely high temperatures and pressures. Only half of drilled geothermal wells lead to a productive site. Enhanced geothermal wells require technologies, proven in natural gas and oil production, that can increase output and yield of productive wells. Techniques such as fracking and zonal isolation require monitoring electronics that can operate at the much higher temperature and pressures than oil and gas wells experience. Measurement of flow, in particular, is an electromechanical challenge, but opens the opportunity for in-well power generation, alleviating the need for batteries or additional cabling. Ozark IC is a leader in the development of integrated Silicon Carbide (SiC) circuits and is actively developing circuits for NASA, suitable for operation on the surface of Venus – with temperatures up to 500oC and pressures up to 100 bar nominal – not unlike subterranean conditions on earth. Ozark IC’s partner, Honeybee Robotics, has developed advanced motors that can operate in this environment. A unique opportunity exists to combine these technologies to create next-generation down hole flow sensing instruments. Present-day systems only last 4-6 hours in this environment; SiC technology can withstand 1,000s of hours in these conditions. The thrust of the proposed DOE Phase I program is to validate Ozark IC’s electronics and Honeybee Robotics’ motors in a generator configuration for flow sensing and power generation in enhanced geothermal well conditions. Ozark IC will characterize energy storage devices and integrated circuits suitable for power generation, storage and flow sensing using SiC technology. Honeybee Robotics will work with Ozark IC to validate its motor modules in a generator configuration and will design a turbine for this harsh environment. A complete flow sensing system will be demonstrated through hardware-validated simulation models in preparation for module fabrication and in-field test in Phase II. In addition to its application in enhanced geothermal wells, the anticipated public benefits of the proposed research begin with enabling next generation oil and gas exploration and well monitoring. The technology can also be applied to aerospace applications to enable higher performance turbine engines, and may ultimately be applied to automotive applications to improve the control and efficiency of internal combustion engines.