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. Enhanced geothermal systems (EGS) require drilling deep and hot wells; while making better use of each well through techniques such as fracking and zonal isolation. Establishing a well requires monitoring electronics that can produce temperature, pressure and flow profiles in these deep (10,000+ feet) wells that can experience temperatures as high as 450°C. Present-day electronic systems only last 4-6 hours in this environment, and even fiber optic systems (that only monitor temperature) cannot survive for the 30 days above the 200°C experienced in the establishment of a well. 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 (HBR), has developed advanced motors that can operate in this environment. In Phase I, Ozark IC and HBR demonstrated, using environmental laboratory testing, that these technologies can be combined to create next-generation down hole instruments with self-powered capability. By using SiC technology, instruments can withstand 1,000s of hours in these conditions. The thrust of Phase II is a flow, temperature and pressure system that will not only meet EGS needs up to 500oC but is also designed to be networkable through the use of SiC electronic “smart nodes”. The prototype electronic sensor nodes will be designed to work in this subterranean environment (up to 500°C, 150 bar) for no less than 300 hours. Each smart node contains a data acquisition module that contains a sensor and SiC integrated circuits that digitize the sensor data and communicate it to the surface. Modules can be configured to measure temperature, pressure and/or flow, all placed on a high-temperature ceramic platform. Honeybee Robotics will fabricate a turbine and generator which will be used for both power generation and flow sensing.Commercial Applications and Other BenefitsIn 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.