Thermal Characteristics of the Chena Hot Springs Alaska Geothermal System

Jump to: navigation, search


OpenEI Reference LibraryAdd to library

Conference Paper: Thermal Characteristics of the Chena Hot Springs Alaska Geothermal System

Abstract
Chena Hot Springs is located in the east-central partof the Alaska within the Yukon-Tanana Plateau,about 75 km east of Fairbanks. It is a moderatetemperature deep circulation system typical ofinterior Alaska. The main shallow upflow zone isabout 2000 ft long and 300 ft wide. The system islocated at the edge of a granitic body where deepcirculating geothermal waters reach the surface byway of fractures along the contact with surroundinghost rocks. The hot springs discharge at temperaturesaround 165 °F (74 °C); nevertheless, the geochemicaldata suggest the source temperatures to be around 250 °F (121 °C). With current drilling activities to1020 ft (311 m), temperatures of up to 176 °F (80 °C)have been measured.The temperature and pressure data from the currentwells show that the geothermal system is similar tothe Basin-and-Range type geothermal systems. Thissimilarity allowed application of most of theexploration methods that are used in otherfault/fracture related systems. These include adetailed geological study of the area, AMT, anairborne gamma ray spectroscopy, EM and magneticsurvey, and drilling with reservoir analysis. The smallsize of the system has enabled us to apply theconventional exploration methods with better control.The system is attractive as it is smaller in scalecompared to most of the Basin-and-Range systems,but still showing a similar complex hydrologiccharacter.So far, 11 exploration wells have been drilled as partof a DOE-GRED contract and 7 wells by the resortwith depths 300ft-1000 ft. The highest temperaturesin the 700-1000 ft depth range are found about 1000ft west of the main hot springs vent area and thegeothermal waters here show highest concentrationof helium and dissolved solids. The location and sizeof the deeper high temperature system are not clearlyunderstood with current drilling data because of thehigh permeability zone at shallow depth. The wells atboth ends of the shallow convective zone havegradients two or three times the regional backgroundwhich suggests the deep source is spread in a muchwider area relative to the shallow zone. Currently,one 700 ft deep well with flow rate of 500 gpm hasbeen used for running a 250 kWh power unit. Furtherdeeper drilling has been proposed in order tounderstand the deep thermal regime. If the high targettemperatures are reached at exploitable depths withsufficient flow rates, the production capacity could be1-10 MW. The electricity production is possible inthis low enthalpy system as a result of low surfacetemperatures relative to the moderate subsurfacetemperatures.

Authors 
Kamil Erkan, Gwen Holdman, David Blackwell and Walter Benoit






Conference 
Stanford Geothermal Workshop; {{{ConferencePlace}}}"{{{ConferencePlace}}}" cannot be used as a page name in this wiki.; 2007


Published 
PROCEEDINGS, Thirty-Second Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California;, 2007





DOI 
Not Provided
Check for DOI availability: http://crossref.org


Online 
Internet link for Thermal Characteristics of the Chena Hot Springs Alaska Geothermal System

Citation

Kamil Erkan,Gwen Holdman,David Blackwell,Walter Benoit. 2007. Thermal Characteristics of the Chena Hot Springs Alaska Geothermal System. In: PROCEEDINGS, Thirty-Second Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California. Stanford Geothermal Workshop; 2007; (!) . (!) : (!) ; p. (!)


Related Geothermal Exploration Activities
Activities (1)


Areas (1)
  1. Chena Geothermal Area
Regions (0)