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Significance of carbonate buffers in natural waters reacting with supercritical CO 2 : Implications for monitoring, measuring and verification (MMV) of geologic carbon sequestration
Author(s) -
Newell Dennis L.,
Kaszuba John P.,
Viswanathan Hari S.,
Pawar Rajesh J.,
Carpenter Thomas
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2008gl035615
Subject(s) - siliciclastic , carbonate , carbon sequestration , geology , brine , aquifer , geochemistry , carbonate minerals , carbonate rock , groundwater , mineralogy , environmental science , carbon dioxide , dolomite , sedimentary rock , chemistry , geomorphology , geotechnical engineering , facies , organic chemistry , structural basin
Successful geologic sequestration of carbon in deep saline aquifers requires accurate predictive models of rock‐brine‐CO 2 interaction. Often overlooked in siliciclastic‐hosted saline reservoirs is the carbonate buffering of the groundwater. Carbonate minerals are ubiquitous, even in siliciclastic host rocks, resulting in some carbonate buffering. Geochemical modeling of rock‐brine‐CO 2 systems often do not accurately predict the geochemical evolution of the system leading to significant doubts in predicting the performance of carbon repositories. New data from a simple NaCl brine‐plagioclase hydrothermal experiment tests carbon sequestration in dawsonite and sensitivity to carbonate buffering. This is contrasted to a NaCl brine ‐ siliciclastic rock system containing some initial bicarbonate buffering, analogous to most saline‐aquifer sequestration targets, and show that critical errors are caused by incomplete or inaccurate characterization of the in situ geochemistry. We provide a methodology that accurately predicts the in situ condition using samples collected from brine‐rock‐CO 2 experiments or well‐heads in a carbon sequestration monitoring scenario.