Scientists estimate that the temperature of the earth’s inner core is about 10,800 degrees Fahrenheit (°F). As that heat escapes to the surface of the earth it warms the rocks and fluids of the crust. While the geothermal gradient varies from place to place, in general the temperature of the earth’s crust increases by about 15 °F for every 1000 feet increase in depth. The principle of geothermal energy power production is, simply put, that one can harvest heat from the earth by circulating cold fluids through hot rocks found at depth and return the warm fluids to the surface to drive turbines that generate electricity. Limiting factors on this process include the temperature of the earth that can be economically accessed (the hotter the better) and the efficiency of the heat transfer in the rocks which is related to the permeability of the rock that is accessed. Traditional geothermal power applications have used the natural fracture system in the rocks at depth to act as the conduits for the fluids that are being heated. Enhanced Geothermal Systems are created by inducing more fractures into the hot rocks in order to increase surface area of hot rock contacted by the fluids thus increasing the efficiency of heat exchange.
The Fenton Hill New Mexico Hot Dry Rock program of the 1970’s demonstrated the potential of the EGS approach. Today modern hydraulic shearing and fracturing methodologies developed during the shale revolution are being ported to the geothermal industry in support of EGS, just as in hydrocarbon applications, such fracture processes need to be monitored to image the fractures created and ensure the proper development of an appropriately fractured reservoir for optimal heat exchange.
Being the world leader in hydraulic fracture microseismic monitoring, MSI has the domain knowledge and experience to accomplish this imaging.
To learn more about Geothermal Monitoring, please contact MicroSeismic.