Enhanced Geothermal Systems

Progress on the Desert Peak East EGS Project

Basic Information
Author: 
Robertson-Tait, A.
Author: 
Johnson, S.
Description: 
An industry-DOE cost-shared project is underway to evaluate the technical feasibility of developing an EGS power generation project on the eastern side of the Desert Peak geothermal field. An existing well (DP 23-1) is the focus of much of the Phase I investigation, including re-interpretation of lithology, acquisition and analysis of a well bore imaging log, conducting and analyzing a step-rate injection test, performing a "mini-frac" to determine the magnitude of the least principal stress, and re-completing the well in preparation for hydraulic stimulation in Phase II. In addition, numerical modeling has been undertaken to estimate heat recovery and make generation forecasts for various stimulated volumes and well configurations.
Publication Date: 
Saturday, January 1, 2005
Resource Language: 
English
Intelectual Originator Contact
Organization Name: 
GeothermEx, Inc.
Street Address: 
3260 Blume Drive,Suite 220
City: 
Richmond
State/Province: 
CA
Postal Code: 
94806
Country: 
United States
Phone: 
510-527-9876
Fax: 
510-527-8164
Resource Information
Access Statement: 
Abstract available online at http://www.geothermex.com/files/file_4858299a2e4ab.pdf For a copy of this paper please e-mail us at mw@geothermex.com
Resource Distribution Contact
Organization Name: 
GeothermEx, Inc.
Street Address: 
3260 Blume Drive,Suite 220
City: 
Richmond
State/Province: 
CA
Postal Code: 
94806
Country: 
United States
Phone: 
510-527-9876
Fax: 
510-527-8164
Geographic Extent
North bounding latitude: 
39.9838
South bounding latitude: 
39.6674
West bounding longitude: 
-119.174
East bounding longitude: 
-118.754
Previous Citation
Bibliographic Citation: 
Ann Robertson-Tait, and Stuart Johnson, 2005. Progress on the Desert Peak East EGS Project. GeothermEx, Inc.,Richmond, California. ORMAT Nevada, Inc., Reno, Nevada

Progress and Future Plans at the Desert Peak East EGS Project

Basic Information
Author: 
Robertson-Tait, A.
Author: 
Morris, C.
Description: 
An industry-DOE cost-shared project is underway to evaluate the technical feasibility of developing an EGS power generation project on the eastern side of the Desert Peak geothermal field. Analysis of existing geological and geophysical data is complemented by new geologic mapping and gravity work in the Hot Springs Mountains undertaken by researchers with funding from the Great Basin Center for Geothermal Energy at the University of Nevada Reno (UNR). An existing well (DP 23-1) is the focus of much of the Phase I investigation, including re-interpretation of lithology, acquisition and analysis of a well bore imaging log, and conducting and analyzing a step-rate injection test. As of June 2003, the project is about half complete; results are summarized below. Phase I work remaining to modeling, numerical modeling and the development of a be completed includes conceptual detailed plan to guide upcoming field activities.
Publication Date: 
Sunday, February 2, 2003
Resource Language: 
English
Intelectual Originator Contact
Organization Name: 
GeothermEx, Inc.
Street Address: 
3260 Blume Drive,Suite 220
City: 
Richmond
State/Province: 
CA
Postal Code: 
94806
Country: 
United States
Phone: 
510-527-9876
Fax: 
510-527-8164
Resource Information
Access Statement: 
Abstract available online at http://www.geothermex.com/files/Robertson-Tait_2003-1.pdf For a copy of this paper please e-mail us at mw@geothermex.com
Resource Distribution Contact
Organization Name: 
GeothermEx, Inc.
Street Address: 
3260 Blume Drive,Suite 220
City: 
Richmond
State/Province: 
CA
Postal Code: 
94806
Country: 
United States
Phone: 
510-527-9876
Fax: 
510-527-8164
Geographic Extent
North bounding latitude: 
39.9564
South bounding latitude: 
39.6801
West bounding longitude: 
-119.224
East bounding longitude: 
-118.814
Previous Citation
Bibliographic Citation: 
Ann Robertson Tait, and Christy Morris, 2000. Progress and Future Plans at the Desert Peak East EGS Project. GeothermEx, Inc.,Richmond, California. ORMAT Nevada, Inc., Reno, Nevada

Potential for "Enhanced Geothermal Systems" In The Western United States

Basic Information
Author: 
Sass, J.H.
Author: 
Robertson-Tait, Ann
Description: 
Most presently active or contemplated hot dry rock (HDR) projects vary significantly from the original HDR concept of creating an engineered reservoir in an effectively impermeable medium. Instead, they form part of a spectrum of geothermal resources that exhibit less-than-commercial productivity, but are not completely impermeable. A new working definition, "Enhanced Geothermal Systems" (EGS), is now being used to describe all but the high-grade hydrothermal portion of the geothermal resource spectrum. To promote the commercial development of these lower permeability and/or fluid-deficient resources, EGS research and development in the U.S. during the next few years is likely to include field experiments that target hot, low permeability zones within or near the margins of commercially developed hydrothermal systems. These systems are located in areas of elevated regional heat flow (Cascade Range, Basin and Range Province, Salton Trough, California Coast Ranges and Rio Grande Rift Zone), where temperatures of 250°C can be reached at depths of 4 km or less. Potential sites for EGS experiments were identified with the objective of yielding immediate benefits to the geothermal industry while also contributing to the commercial development of an incrementally broader range of geothermal resources.
Publication Date: 
Thursday, January 1, 1998
Resource Language: 
English
Intelectual Originator Contact
Organization Name: 
GeothermEx, Inc.
Street Address: 
3260 Blume Drive,Suite 220
City: 
Richmond
State/Province: 
CA
Postal Code: 
94806
Country: 
United States
Phone: 
510-527-9876
Fax: 
510-527-8164
Resource Information
Access Statement: 
Abstract available online at http://www.geothermex.com/files/Robertson-Tait_1998-1.pdf For a copy of this paper please e-mail us at mw@geothermex.com
Resource Distribution Contact
Organization Name: 
GeothermEx, Inc.
Street Address: 
3260 Blume Drive,Suite 220
City: 
Richmond
State/Province: 
CA
Postal Code: 
94806
Country: 
United States
Phone: 
510-527-9876
Fax: 
510-527-8164
Geographic Extent
North bounding latitude: 
38.9106
South bounding latitude: 
34.6901
West bounding longitude: 
-123.047
East bounding longitude: 
-116.719
Previous Citation
Bibliographic Citation: 
John H. Sass and Ann Robertson-Tait, 1998. POTENTIAL FOR "ENHANCED GEOTHERMAL SYSTEMS" IN THE WESTERN UNITED STATES. GeothermEx, Inc.,Richmond, California. U.S. Geological Survey, Flagstaff, Arizona

Geologic Characterization of Pre-Tertiary Rocks at the Desert Peak East EGS Project Site, Churchill County, Nevada

Basic Information
Author: 
Lutz, S.J.
Author: 
Schriener Jr., A.
Author: 
Schochet, D.
Author: 
Robertson-Tait, Ann
Description: 
A DOE-Industry cost-shared project is underway at Desert Peak East, located within the Hot Springs Mountains, northwestern Churchill County, approximately SO miles (80.S km) northeast of Reno, Nevada. The potential reservoir under investigation is contained within pre-Tertiary metamorphic and granitic rocks with temperatures exceeding 400°F (204°C). The purpose of the geologic study is to determine the lateral and vertical extent of basement lithologies, and the character and mineralogy of natural fracturing in the rocks to identify suitable targets for hydrofracturing and stimulation in subsequent phases of this enhanced geothermal system (EGS) project.
Publication Date: 
Sunday, October 12, 2003
Resource Language: 
English
Intelectual Originator Contact
Organization Name: 
GeothermEx, Inc.
Street Address: 
3260 Blume Drive,Suite 220
City: 
Richmond
State/Province: 
CA
Postal Code: 
94806
Country: 
United States
Phone: 
510-527-9876
Fax: 
510-527-8164
Resource Information
Access Statement: 
Abstract available online at http://www.geothermex.com/files/Robertson-Tait_2003-2.pdf For a copy of this paper please e-mail us at mw@geothermex.com
Resource Distribution Contact
Organization Name: 
GeothermEx, Inc.
Street Address: 
3260 Blume Drive,Suite 220
City: 
Richmond
State/Province: 
CA
Postal Code: 
94806
Country: 
United States
Phone: 
510-527-9876
Fax: 
510-527-8164
Geographic Extent
North bounding latitude: 
39.7403
South bounding latitude: 
39.4567
West bounding longitude: 
-118.667
East bounding longitude: 
-118.31
Previous Citation
Bibliographic Citation: 
Lutz, S.J., Schriener Jr., A., Schochet, D., and Robertson-Tait, A., 2003. Geologic Characterization of Pre-Tertiary Rocks at the Desert Peak East EGS Project Site, Churchill County, Nevada . GeothermEx Inc., Richmond, California.Energy and Geoscience Institute, University of Utah, Salt Lake City, Utah. Earthrock Consulting, Bermuda Dunes, California. ORMAT Nevada Inc., Sparks, Nevada.

Cost of Electric Power from Enhanced Geothermal Systems — Its Sensitivity and Optimization

Basic Information
Author: 
Sanyal, S.K.
Description: 
Based on a review of the Enhanced Geothermal Systems (EGS) developed to date worldwide, numerical simulation of idealized EGS reservoirs, economic sensitivity analysis, and practical considerations of some site characteristics, this paper shows that certain steps can be taken towards minimizing the levelized cost of electric power from EGS systems; these steps are as follows: (a) choosing the site with the highest possible vertical temperature gradient and for the thickest possible sedimentary cover on the basement; (b) choosing the drilling depth that maximizes a well’s power capacity per unit drilling cost rather than reaches the hottest resource; (c) creating the largest possible stimulated volume per well; (d) increasing per well productivity by stimulating multiple, “vertically stacked” zones and/or increasing the pumping rate of production wells taking advantage of the evolving advances in pump technology; (e) improving stimulation effectiveness, and particularly, reducing the fracture spacing and heterogeneity in the hydraulic characteristics of the stimulated volume; (f) through reservoir modeling, optimizing well spacing and injection rates that minimize the rate of decline in net generation with time (g) reducing the power plant cost; (h) developing multiple, contiguous EGS units to benefit from the economy of scale; and (i) reducing the operations and maintenance cost. The basis for these conclusions is presented in the paper.
Publication Date: 
Thursday, January 1, 2009
Resource Language: 
English
Intelectual Originator Contact
Organization Name: 
GeothermEx, Inc.
Street Address: 
3260 Blume Drive,Suite 220
City: 
Richmond
State/Province: 
CA
Postal Code: 
94806
Country: 
United States
Phone: 
510-527-9876
Fax: 
510-527-8164
Resource Information
Access Statement: 
Abstract available online at http://www.geothermex.com/files/file_4a8dad8ae2bf2.pdf For a copy of this paper please e-mail us at mw@geothermex.com
Resource Distribution Contact
Organization Name: 
GeothermEx, Inc.
Street Address: 
3260 Blume Drive,Suite 220
City: 
Richmond
State/Province: 
CA
Postal Code: 
94806
Country: 
United States
Phone: 
510-527-9876
Fax: 
510-527-8164
Geographic Extent
North bounding latitude: 
42.5069
South bounding latitude: 
33.3791
West bounding longitude: 
-124.453
East bounding longitude: 
-113.555
Previous Citation
Bibliographic Citation: 
Subir K. Sanya, 2009. Cost of Electric Power from Enhanced Geothermal Systems — Its Sensitivity and Optimization. GeothermEx, Inc., Richmond, California.
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