EGS

Utility of the Data Gathered From the Fenton Hill Project for Development of Enhanced Geothermal Systems

Basic Information
Author: 
Robertson-Tait, A.
Author: 
Klein, C.W.
Author: 
McLarty, L.
Description: 
To prioritize information for archiving and to determine the applicability of the Fenton Hill experience to the future development of Enhanced Geothermal Systems (EGS), an integrated review was made of five categories of Fenton Hill information: hydraulic fracturing data, well logs, seismic data, flow test data and tracer test data. Major experiments were identified, the methods of data collection and analysis were determined, the location and format of the data were determined, and further analyses that would yield information of value to EGS developers were suggested. Such analyses would be directed toward the determination of: I) if and how the state of stress in the reservoir changed during sequential fracturing jobs; 2) how the orientation of fractures changed with depth and location; 3) how the reservoir size increased as fracturing and flow testing operations proceeded; 4) how the hydraulic properties and heat-transfer characteristics of the reservoir varied with changes in operating conditions; and 5) how the Phase II reservoir (the deeper and hotter of the two reservoirs developed) would behave over the long term under various operating conditions.
Publication Date: 
Saturday, January 1, 2000
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
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: 
36.0345
South bounding latitude: 
35.7184
West bounding longitude: 
-106.729
East bounding longitude: 
-106.293

Tracer Testing at the Desert Peak EGS Project

Basic Information
Author: 
Rose, P.
Author: 
Leecaster, K.
Author: 
Drakos, P.
Author: 
Robertson-Tait, A.
Description: 
As part of the Desert Peak EGS project, tracer testing was conducted involving two existing injection wells at the Desert Peak geothermal field. The tracer data showed very strong returns from both injectors to one of the production wells, with much lower returns to the remaining producers. The tracer-swept pore volume was estimated using a first-moment analysis of the return-curve data.
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
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: 
39.8321
South bounding latitude: 
39.6801
West bounding longitude: 
-119.062
East bounding longitude: 
-118.825

Review of the State-Of-The-Art of Numerical Simulation of Enhanced Geothermal Systems

Basic Information
Author: 
Sanyal, S.K.
Author: 
Butler, S.J.
Author: 
Swenson, D.
Author: 
Hardeman, B.
Description: 
Under the premise that the behavior of enhanced geothermal systems (EGS) will be dominated by fracture flow, this paper reviews the special features that would be required of any practical numerical simulator for EGS. These features, required in addition to the basic features of conventional geothermal simulators, namely, the ability to handle two-phase fluid flow, heat transfer and tracer transp0l1 in porous and fractured media, are: explicit representation of fractures, change in fracture aperture due to effective stress and shear, thermo-elastic effects, relation between fracture aperture and conductivity, and channeling of fluid flow within fractures. Chemical reaction between water and rock and coupling of the reservoir model with a well bore model would also be desirable features.
Publication Date: 
Monday, January 1, 2001
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/Sanyal_2000-7.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: 
38.7737
South bounding latitude: 
35.4096
West bounding longitude: 
-122.52
East bounding longitude: 
-117.422
Previous Citation
Bibliographic Citation: 
Sanyal, S.K., Butler, S.J., Swenson, D., and Hardeman, B., 2001. Review of the State-Of-The-Art of Numerical Simulation of Enhanced Geothermal Systems. GeothermEx, Inc.,Richmond, California. Thunderhead Engineering Consultants, Inc., Manhattan, Kansas

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 Sites and Experiments for Enhanced Geothermal Systems In The Western United States

Basic Information
Author: 
Robertson-Tait, Ann
Author: 
Lovekin, J.W.
Description: 
The Department of Energy's EGS Strategic Plan anticipates that EGS experimentation in the United States will be underway by 2004 in areas within or adjaeent to commerciallydeveloped hydrothermal fields, and that an EGS demonstration plant will begin operating in 2008. Criteria for selecting sites for EGS experimentation focus on enhancing energy recovery at producing fields while advancing the EGS knowledge base incrementally towards a demonstration project. With input from field operators, basic characteristics and information on the type of EGS work that may be undertaken are presented for 15 producing fields and 2 unexploited fields. Six producing fields meet 90 - 100% of the site selection criteria and 9 meet 60 - 70%. The use of EGS techniques to supply an existing facility has the advantages of low cost, support from the geothermal industry and demonstration of applicability to a variety of conversion technologies. This approach seeks to reduce EGS risk and uncertainty, promoting the transition from research to commercial evelopment.
Publication Date: 
Saturday, January 1, 2000
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_4858281834f72.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: 
38.4991
South bounding latitude: 
35.8382
West bounding longitude: 
-121.992
East bounding longitude: 
-117.07
Previous Citation
Bibliographic Citation: 
Ann Robertson-Tait and James Loveki, 2000. Potential Sites and Experiments for Enhanced Geothermal Systems In The Western United States. GeothermEx, Inc.,Richmond, California.

Is EGS Commercially Feasible?

Basic Information
Author: 
Sanyal, S.K.
Author: 
Morrow, J.W.
Author: 
Butler, S.J.
Author: 
Robertson-Tait, Ann
Description: 
This paper presents an evaluation of the cost of electric power from Enhanced Geothermal Systems (EGS), that is, reservoirs with sub-commercial permeability enhanced by hydraulic stimulation. The parameters in this exercise reflect the conditions encountered at the Desert Peak EGS project in Nevada, but the results should be applicable, at least qualitatively, to any EGS project. The approach taken is to : 1) use numerical simulation to evaluate energy recovery versus time over an assumed 30-year project life for various system configurations (number and spacing of wells, assumptions about stimulation effectiveness, etc; 2) estimate the levelized power cost for each configuration, based on capital cost, O&M cost, the cost of money and inflation rate (using Monte Carlo sampling to address uncertainties); 3) determining the sensitivity of levelized cost to the cost components, interest and inflation rates, and resource characteristics (maximum practical pumping rate, reservoir characteristics, and the depth to thereservoir at the site); and 4) estimating future EGS costs and considering the possible technology improvements that could be made by that time.
Publication Date: 
Monday, January 1, 2007
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
Available Files: 
Resource Information
Access Statement: 
Abstract available online at http://www.geothermex.com/files/Sanyal_2007-5.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: 
34.5454
West bounding longitude: 
-123.047
East bounding longitude: 
-117.07
Previous Citation
Bibliographic Citation: 
Sanyal, S.K., Morrow, J.W., Butler, S.J., and Robertson-Tait, A., 2007. Is EGS Commercially Feasible? GeothermEx, Inc., Richmond, California.

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.

An Analysis of Power Generation Prospects from Enhanced Geothermal Systems

Basic Information
Author: 
Sanyal, S.K.
Author: 
Butler, S.J.
Description: 
This paper presents an analysis of power generation prospects from Enhanced Geothermal Systems (EGS), specifically, reservoirs with subcommercial permeability enhanced by hydraulic stimulation. EGS is also known as “hot dry rock” or “hot fractured rock” systems. The performance under consideration here is the net electrical power delivered as a function of time over the 20-to-30 year life of a power plant. Although the parameters in this exercise generally reflect conditions encountered at the Desert Peak EGS project in the State of Nevada, United States, the conclusions are applicable, at least qualitatively, to any EGS project.
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/Sanyal_2005-2.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: 
41.7245
South bounding latitude: 
34.1099
West bounding longitude: 
-124.805
East bounding longitude: 
-115.84
Previous Citation
Bibliographic Citation: 
Subir K. Sanyal and Steven J. Butle, 2005. An Analysis of Power Generation Prospects from Enhanced Geothermal Systems. GeothermEx, Inc., Richmond, California.

An Alternative and Modular Approach to Enhanced Geothermal Systems

Basic Information
Author: 
Sanyal, S.K.
Author: 
Granados, E.E.
Author: 
Butler, S.J.
Author: 
Horne, R.N.
Description: 
This paper describes a low-risk, low-cost and modular alternative to the conventional Hot Dry Rock or Enhanced Geothermal Systems (EGS). In this approach, which we have named the Earth Energy Extraction System (“Triple- E” System), the injected fluid is allowed to get preheated in the injection wellbore before reaching the reservoir; this preheating is achieved through injection in ultra-slim diameter wells (2.5 to 7.5cm) and by keeping the rate of injection very low (on the order of 10 liters per second). The injected fluid then heats up further as it travels to the production well through pores and fractures in the rock. The injection wells are terminated close to and at a shallower level than the top of the productive interval in the production well. This approach avoids the two main technical limitations associated with conventional EGS: (a) creating a significant reservoir volume by artificial fracturing; and (b) fluid loss control. This approach reduces dependence on the occurrence of natural permeability that limits the scope of conventional geothermal technology. The risk of cooling of the production well by shortcircuiting of injected water, a common concern in both EGS and conventional geothermal projects, is significantly reduced by preheating of the injected water.
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/Sanyal_2005-1.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: 
41.9864
South bounding latitude: 
32.9376
West bounding longitude: 
-123.926
East bounding longitude: 
-114.434
Previous Citation
Bibliographic Citation: 
Sanyal, S.K., Granados, E.E., Butler, S.J., and Horne, R.N., 2005. An Alternative and Modular Approach to Enhanced Geothermal Systems. GeothermEx, Inc., Richmond, California.
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