Tuesday, September 26, 2017

Science & Technology: Using Acoustic Emissions to Understand Enhanced Geothermal Systems Processes

Listening to the Earth to harness geothermal energy (Sanford Underground Research Facility)

Hunter Knox and Bill Roggenthen from South Dakota School of Mines lower sensors down a set of holes that were drilled for the kISMET experiment. (Matthew Kapust)
The goal of the Lawrence Berkeley National Laboratory led EGS Collab project is to collect data that will allow the team to create better predictive and geomechanic models that will allow them to better understand the subsurface of the earth. The team will drill two boreholes: one for injection and one for production. Each will be 60 meters long in the direction of the minimum horizontal stress. Six additional monitoring boreholes will contain seismic, electrical and fiber optic sensors.

When the holes are drilled, the team will place “straddle packers”—a mandrel, or pipe, with two deflated balloons on either end—inside them. Once inside, they will inflate the balloons and flow water down the pipe to create an airtight section. They will continue to pump water until the rock fractures and use the monitoring equipment to listen for acoustic emissions, the sounds that will tell them what is happening within the rock.

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