POROELASTIC TOMOGRAPHY BY ADJOINT INVERSE MODELING OF DATA Award Number: DE-EE0006760 CX(s) Applied: A9 Geothermal Technologies Office Date: 09/11/2014 Location(s): WI Office(s): Golden Field Office
Office of NEPA Policy and Compliance
February 25, 2016
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POROELASTIC TOMOGRAPHY BY ADJOINT INVERSE MODELING OF DATA
Award Number: DE-EE0006760
CX(s) Applied: A9
Geothermal Technologies Office
Date: 09/11/2014
Location(s): WI
Office(s): Golden Field Office
The University of Wisconsin – Madison (UWM) would utilize DOE and cost share funding to quantify reservoir complexity for characterizing and managing the Enhanced Geothermal System (EGS) at Brady Hot Springs, Nevada. The objective of the project is to assess an integrated technology for characterizing and monitoring changes in an EGS reservoir in three dimensions with a spatial resolution better than 50 meters. A previous NEPA Determination (GFO-0006760-001; CX A9; 09/11/14) approved all project tasks except Task 6. This NEPA Determination is specific to Task 6 activities only.
Task 6 of the project is an innovative geophysical survey known as Poroelastic Tomography (PoroTomo) that would take place at the Brady geothermal power plant site located approximately 19 miles northeast of Fernley, Nevada in Churchill County on private lands and public lands administered by the Bureau of Reclamation (BOR) and the Bureau of Land Management (BLM) Winnemucca District, Humboldt River Field Office. The PoroTomo survey would combine seismic geophysical techniques (270 seismometers installed) with high-resolution fiber optic cable sensors (29,300 linear feet of cabling) to produce detailed three-dimensional images of the site’s geology and structure (faults). The seismic signal would mostly be generated by a vibroseis truck at approximately 215 locations, most of which are planned along existing roads, on the shoulder of existing paved roads, or within existing disturbance. No new roads would be constructed. Any new surface disturbance from the vibroseis would be limited to cross-country travel. The survey would measure seismic responses over the area of the test site while varying the production and injection rates of different wells to further define the structures and fluid flow paths without the high costs of deep exploration drilling. Sundry notices for sensor deployment within existing geothermal wells on private property would be obtained from the Nevada Division of Minerals prior to deployment. No other permits or modification to permits would be needed for work occurring on private property.