Evaluation of CO2-Fluid-Rock Interaction in Enhanced Geothermal Systems: Field-Scale Geochemical Simulations
Recent studies suggest that using supercritical CO2 (scCO2) instead of water as a heat transmission fluid in Enhanced Geothermal Systems (EGS) may improve energy extraction. While CO2-fluid-rock interactions at “typical” temperatures and pressures of subsurface reservoirs are fairly well known, such...
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Wiley
2017-01-01
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| Series: | Geofluids |
| Online Access: | http://dx.doi.org/10.1155/2017/5675370 |
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| author | Feng Pan Brian J. McPherson John Kaszuba |
| author_facet | Feng Pan Brian J. McPherson John Kaszuba |
| author_sort | Feng Pan |
| collection | DOAJ |
| description | Recent studies suggest that using supercritical CO2 (scCO2) instead of water as a heat transmission fluid in Enhanced Geothermal Systems (EGS) may improve energy extraction. While CO2-fluid-rock interactions at “typical” temperatures and pressures of subsurface reservoirs are fairly well known, such understanding for the elevated conditions of EGS is relatively unresolved. Geochemical impacts of CO2 as a working fluid (“CO2-EGS”) compared to those for water as a working fluid (H2O-EGS) are needed. The primary objectives of this study are (1) constraining geochemical processes associated with CO2-fluid-rock interactions under the high pressures and temperatures of a typical CO2-EGS site and (2) comparing geochemical impacts of CO2-EGS to geochemical impacts of H2O-EGS. The St. John’s Dome CO2-EGS research site in Arizona was adopted as a case study. A 3D model of the site was developed. Net heat extraction and mass flow production rates for CO2-EGS were larger compared to H2O-EGS, suggesting that using scCO2 as a working fluid may enhance EGS heat extraction. More aqueous CO2 accumulates within upper- and lower-lying layers than in the injection/production layers, reducing pH values and leading to increased dissolution and precipitation of minerals in those upper and lower layers. Dissolution of oligoclase for water as a working fluid shows smaller magnitude in rates and different distributions in profile than those for scCO2 as a working fluid. It indicates that geochemical processes of scCO2-rock interaction have significant effects on mineral dissolution and precipitation in magnitudes and distributions. |
| format | Article |
| id | doaj-art-2a426ab7d95540efbd74fc3550979cf4 |
| institution | Kabale University |
| issn | 1468-8115 1468-8123 |
| language | English |
| publishDate | 2017-01-01 |
| publisher | Wiley |
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| series | Geofluids |
| spelling | doaj-art-2a426ab7d95540efbd74fc3550979cf42025-02-03T01:31:02ZengWileyGeofluids1468-81151468-81232017-01-01201710.1155/2017/56753705675370Evaluation of CO2-Fluid-Rock Interaction in Enhanced Geothermal Systems: Field-Scale Geochemical SimulationsFeng Pan0Brian J. McPherson1John Kaszuba2Energy & Geoscience Institute, The University of Utah, Salt Lake City, UT 84108, USAEnergy & Geoscience Institute, The University of Utah, Salt Lake City, UT 84108, USADepartment of Geology & Geophysics, The University of Wyoming, Laramie, WY 82071, USARecent studies suggest that using supercritical CO2 (scCO2) instead of water as a heat transmission fluid in Enhanced Geothermal Systems (EGS) may improve energy extraction. While CO2-fluid-rock interactions at “typical” temperatures and pressures of subsurface reservoirs are fairly well known, such understanding for the elevated conditions of EGS is relatively unresolved. Geochemical impacts of CO2 as a working fluid (“CO2-EGS”) compared to those for water as a working fluid (H2O-EGS) are needed. The primary objectives of this study are (1) constraining geochemical processes associated with CO2-fluid-rock interactions under the high pressures and temperatures of a typical CO2-EGS site and (2) comparing geochemical impacts of CO2-EGS to geochemical impacts of H2O-EGS. The St. John’s Dome CO2-EGS research site in Arizona was adopted as a case study. A 3D model of the site was developed. Net heat extraction and mass flow production rates for CO2-EGS were larger compared to H2O-EGS, suggesting that using scCO2 as a working fluid may enhance EGS heat extraction. More aqueous CO2 accumulates within upper- and lower-lying layers than in the injection/production layers, reducing pH values and leading to increased dissolution and precipitation of minerals in those upper and lower layers. Dissolution of oligoclase for water as a working fluid shows smaller magnitude in rates and different distributions in profile than those for scCO2 as a working fluid. It indicates that geochemical processes of scCO2-rock interaction have significant effects on mineral dissolution and precipitation in magnitudes and distributions.http://dx.doi.org/10.1155/2017/5675370 |
| spellingShingle | Feng Pan Brian J. McPherson John Kaszuba Evaluation of CO2-Fluid-Rock Interaction in Enhanced Geothermal Systems: Field-Scale Geochemical Simulations Geofluids |
| title | Evaluation of CO2-Fluid-Rock Interaction in Enhanced Geothermal Systems: Field-Scale Geochemical Simulations |
| title_full | Evaluation of CO2-Fluid-Rock Interaction in Enhanced Geothermal Systems: Field-Scale Geochemical Simulations |
| title_fullStr | Evaluation of CO2-Fluid-Rock Interaction in Enhanced Geothermal Systems: Field-Scale Geochemical Simulations |
| title_full_unstemmed | Evaluation of CO2-Fluid-Rock Interaction in Enhanced Geothermal Systems: Field-Scale Geochemical Simulations |
| title_short | Evaluation of CO2-Fluid-Rock Interaction in Enhanced Geothermal Systems: Field-Scale Geochemical Simulations |
| title_sort | evaluation of co2 fluid rock interaction in enhanced geothermal systems field scale geochemical simulations |
| url | http://dx.doi.org/10.1155/2017/5675370 |
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