Conducting a 3D Converted Shear Wave Project to reduce exploration risk at Wister, CA Geothermal Project

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Last modified on July 22, 2011.

Project Title Conducting a 3D Converted Shear Wave Project to reduce exploration risk at Wister, CA
Project Type / Topic 1 Recovery Act: Geothermal Technologies Program
Project Type / Topic 2 Validation of Innovative Exploration Technologies
Project Description UNOCAL discovered this potential resource in the 1988 using widely spaced temperature gradient holes and drilling a exploration well. The UNOCAL exploration well collapsed during drilling preventing testing and reservoir characterization. To define the fractures controlling the Wister geothermal resource, Ormat proposes collecting, processing, and interpretating a 3D seismic survey. Other geophysical data has limited the area of the potential reservoir at Wister, but fracture definition will improve risk associated with drilling a blind geothermal resource. The intent of this project is to use a 3D seismic survey with shear wave conversion combined with available data to site and drill a production well at Wister.

Ormat has initiated an exploration program at Wister that has identified several faults at may control the geothermal reservoir. None of these faults are exposed at the surface. we propose acquiring, processing, and interpreting high resolution 3D seismic data to more accurately map these faults in the subsurface. This data set has been shown to work in the oil exploration industry, but it is thought that it has not been used to target exploratory geothermal drilling in an unproven area. This new acquired information will be merged with previously obtained data to predict the most likely locations for high fracture density and hot fluids.

State California
Objectives To conduct a 3D converted shear wave to reduce exploration risk by characterizing fault geometries at Wister, CA.
Awardees (Company / Institution) Ormat Nevada, Inc.
Awardee Website

Funding Opportunity Announcement DE-FOA-0000109
DOE Funding Level (total award amount) $4,475,015.00
Awardee Cost Share $1,507,980.00
Total Project Cost $5,982,995.00

Principal Investigator(s) Skip Matlick, Ormat Nevada, Inc.

Targets / Milestones The project plans to use the identified locations to site two full-size production wells to test the resource model. These wells will be 4000 to 6000 feet deep, depending on model results, and we will collect core in the wells to study mineralogy, petrology, and fractures. Both wells will have traditional cuttings logs, Formation MicroImager (FMI) logs to quantify fracturing, and flow tests to evaluate reservoir parameters for future production wells.

Location of Project Wister, CA

Impacts Validating an advanced technology to define fractures in a blind geothermal resource to reduce exploration risk in the high potential resource area (Imperial Valley) and potentially applicable to other sedimentary areas.
Funding Source American Recovery and Reinvestment Act of 2009
References EERE Geothermal Technologies Programs[1]


  1. EERE Geothermal Technologies Programs