On modeling of chemical stimulation of an enhanced geothermal system using a high pH solution with chelating agent
Dissolution of silica and calcite in the presence of a chelating agent (NTA) at a high pH was successfully demonstrated in laboratory experiments using a high-temperature flow reactor. (Note that the term 'silica' used here includes amorphous silica, quartz, and silicate glass bead). The mineral dissolution and associated porosity enhancement in the experiments were reproduced by reactive transport modeling using TOUGHREACT. The chemical stimulation method was applied by numerical modeling to a field geothermal injection well system to investigate its effectiveness. Parameters applicable to the quartz monzodiorite unit at the Enhanced Geothermal Systems (EGS) site at Desert Peak (Nevada) were used. Results indicate that the injection of a high pH chelating solution results in dissolution of both calcite and plagioclase, while avoiding precipitation of calcite at high temperature conditions. Consequently reservoir porosity and permeability can be enhanced especially near the injection well. Injection at a lower temperature of 120 C (over 160 C in the base-case) results in a porosity increase that is smaller close to the injection point, but extends to a larger radial distance. A slower kinetic rate results in less aggressive mineral dissolution close to the injection point and larger extent along the flow path, which is favorable for chemical stimulation.
- Research Organization:
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
- Sponsoring Organization:
- Earth Sciences Division
- DOE Contract Number:
- AC02-05CH11231
- OSTI ID:
- 962720
- Report Number(s):
- LBNL-2057E
- Journal Information:
- Geofluids, Journal Name: Geofluids Vol. 9; ISSN 1468-8115
- Country of Publication:
- United States
- Language:
- English
Similar Records
Numerical simulation study of silica and calcite dissolution around a geothermal well by injecting high pH solutions with chelating agent.
Evaluation of C-14 as a natural tracer for injected fluids at theAidlin sector of The Geysers geothermal system through modeling ofmineral-water-gas Reactions
Evaluation of C-14 as a natural tracer for injected fluids at theAidlin sector of The Geysers geothermal system through modeling ofmineral-water-gas Reactions
Conference
·
Sat Jan 31 23:00:00 EST 2009
·
OSTI ID:949970
Evaluation of C-14 as a natural tracer for injected fluids at theAidlin sector of The Geysers geothermal system through modeling ofmineral-water-gas Reactions
Conference
·
Thu Jun 01 00:00:00 EDT 2006
·
OSTI ID:890689
Evaluation of C-14 as a natural tracer for injected fluids at theAidlin sector of The Geysers geothermal system through modeling ofmineral-water-gas Reactions
Conference
·
Thu Jun 01 00:00:00 EDT 2006
·
OSTI ID:890651