Modeling multi-phase non-isothermal fluid flow and reactive geochemical transport in variably saturated fractured rocks: 2. Applications to supergene copper enrichment and hydrothermal flows
Reactive fluid flow and geochemical transport in unsaturated fractured rocks has been of increasing interest to investigators in the areas of geo- and environmental-sciences. To test geochemical hypotheses based on petrologic observation, and to predict geochemical reactions that occur through a complex dynamic interplay of physical and chemical processes, we use the methods presented in a companion paper (part 1, this issue) to investigate two problems: (1) supergene copper enrichment in unsaturated-saturated media, and (2) predicted effects of thermohydrology on geochemistry during the Drift Scale Heater Test at the Yucca Mountain potential nuclear waste repository, Nevada. Through these two examples we address the importance of the following issues on geochemical processes: (1) participation of gas phase in transport and reaction, (2) interactions between fractures and rock matrix for water and chemical constituents, (3) heat effects on fluid flow and reaction properties and processes. In the supergene enrichment system, oxygen gas diffusion from the land surface through fractured rock promotes the alteration of the primary sulfide minerals and the subsequent deposition of secondary minerals. Modeling of the large-scale heater test shows effects of fracture-matrix interaction, heat-driven vaporizing fluid flow, and CO2 degassing on mineral alteration patterns. The two examples also serve as a demonstration of our methods for reactive transport in variably saturated fractured rocks.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Laboratory Directed Research and Development (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 788011
- Report Number(s):
- LBNL-45123; AJSCAP; R&D Project: 366130; TRN: US0110636
- Journal Information:
- American Journal of Science, Vol. 301, Issue 1; Other Information: Journal Publication Date: January, 2001; PBD: 20 May 2000; ISSN 0002-9599
- Country of Publication:
- United States
- Language:
- English
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58 GEOSCIENCES
COPPER ORES
MULTIPHASE FLOW
SULFIDE MINERALS
TEMPERATURE DEPENDENCE
ENVIRONMENTAL TRANSPORT
YUCCA MOUNTAIN
FRACTURED RESERVOIRS
GEOCHEMISTRY
RADIOACTIVE WASTE FACILITIES
ROCK-FLUID INTERACTIONS
HEAT TRANSFER
FLUID FLOW REACTIVE GEOCHEMICAL TRANSPORTFRACTURED ROCK VARIABLY SATURATED MEDIA NUMERICAL MODELING