Geothermal Flow Rate and Liquid/Vapor Fraction Measurement System

Electricity production via geothermal energy has zero emissions and can run 24/7 with little down time. The expansion of output from geothermal well sites will be an important part of the US and world energy future in order to maintain a growing base load while minimizing carbon emissions. To maximize the output and lifespan of a geothermal well, it is beneficial to monitor several parameters, including mass flow rate of both steam and water of the geofluid in real-time. This allows operators to detect changes in well health and to optimize output. Current methods are not sufficiently accurate, cannot be done in real- time, or are cost prohibitive to use for each well individually. This project proposes to develop a real-time flow measurement system that can provide the mass flow rate, liquid/vapor fraction, and the energy content, or enthalpy, to plant operators. A laboratory scale prototype flow measurement system was constructed and installed in a lab test fixture that simulated the flow of steam and water in a geothermal plant. The prototype system performed extremely well, providing real-time flow rate results with accuracy generally within 5%. This is a significant increase over the current flow measurement methods, which have errors as high as 20% and do not provide data real-time. Several prototypes will be developed at full scale and tested both in a laboratory and in actual operating geothermal wells. The field test will prove out the system under real world conditions and showcase the benefits of real-time, accurate data to plant operators. The success of this project will provide a new and unique flow meter for geothermal systems. The data from the measurement system will allow plant operators to track the heat energy from individual wells in real-time, which will provide greater insight on the evolution of geothermal reservoirs over time to maximize efficiency and production potential. Operators will be able to pinpoint the high and low production wells and achieve greater overall production capacity from each geothermal plant.