DOI: 10.1016/j.epsl.2020.116641
论文题名: The role of fluid chemistry on permeability evolution in granite: Applications to natural and anthropogenic systems
作者: Sanchez-Roa C. ; Saldi G.D. ; Mitchell T.M. ; Iacoviello F. ; Bailey J. ; Shearing P.R. ; Oelkers E.H. ; Meredith P.G. ; Jones A.P. ; Striolo A.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2021
卷: 553 语种: 英语
中文关键词: clay mineral precipitation
; dissolution
; fluid-rock interaction
; geothermal systems
; permeability
英文关键词: Alkalinity
; Computerized tomography
; Dissolution
; Feldspar
; Fracture
; Geothermal fields
; Geothermal wells
; Granite
; Precipitation (chemical)
; Rock products
; Anthropogenic systems
; Flow-through experiments
; Fluid-rock interaction
; Mineral dissolution and precipitations
; Permeability evolution
; Permeability measurements
; Reservoir permeability
; X-ray computed tomography
; Petroleum reservoir engineering
; alkalinity
; clay mineral
; dissolution
; effective stress
; fluid composition
; geothermal engineering
; geothermal system
; granite
; igneous geochemistry
; permeability
; precipitation (chemistry)
英文摘要: Efforts to maintain and enhance reservoir permeability in geothermal systems can contribute to sourcing more sustainable energy, and hence to lowering CO2 emissions. The evolution of permeability in geothermal reservoirs is strongly affected by interactions between the host rock and the fluids flowing through the rock's permeable pathways. Precipitation of secondary mineral phases, the products of fluid-rock interactions, within the fracture network can significantly reduce the permeability of the overall system, whereas mineral dissolution can enhance reservoir permeability. The coupling between these two competing processes dictates the long-term productivity and lifetime of geothermal reservoirs. In this study, we simulate the conditions within a geothermal system from induced fracturing to the final precipitation stage. We performed batch and flow-through experiments on cores of the Carnmenellis granite, a target unit for geothermal energy recovery in Cornwall (UK), to understand the role of mineral dissolution and precipitation in controlling the permeability evolution of the system. The physico-chemical properties of the cores were monitored after each reaction-phase using ICP-OES, SEM, hydrostatic permeability measurements, and X-ray Computed Tomography. Results show that permeability evolution is strongly dependent on fluid chemistry. Undersaturated alkaline fluids dissolve the most abundant mineral phases in granite (quartz and feldspars), creating cavities along the main fractures and generating pressure-independent permeability in the core. Conversely, supersaturated alkaline fluids, resulting from extended periods of fluid-rock interactions, promote the precipitation of clay minerals, and decrease the permeability of the system. These results suggest that chemical dissolution during geothermal operations could generate permeable pathways that are less sensitive to effective stress and will remain open at higher pressures. Similarly, maintaining the circulation of undersaturated fluids through these granitic reservoirs can prevent the precipitation of pore-clogging mineral phases and preserve reservoir permeability in granite-hosted geothermal systems. © 2020 The Authors Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165660
Appears in Collections: 气候变化与战略
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作者单位: Department of Earth Sciences, University College London, London, WC1E 6BT, United Kingdom; Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, London, WC1E 6BT, United Kingdom; Géosciences Environnement Toulouse (GET), CNRS, UMR 5563, Observatoire Midi-Pyrénées, 14 Ave. E. Belin, Toulouse, 31400, France; Department of Chemical Engineering, University College London, London, WC1E 6BT, United Kingdom
Recommended Citation:
Sanchez-Roa C.,Saldi G.D.,Mitchell T.M.,et al. The role of fluid chemistry on permeability evolution in granite: Applications to natural and anthropogenic systems[J]. Earth and Planetary Science Letters,2021-01-01,553