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Title: Reactive geochemical transport simulation to study mineral trapping for CO2 disposal in deep saline arenaceous aquifers

A reactive fluid flow and geochemical transport numerical model for evaluating long-term CO{sub 2} disposal in deep aquifers has been developed. Using this model, we performed a number of sensitivity simulations under CO{sub 2} injection conditions for a commonly encountered Gulf Coast sediment to analyze the impact of CO{sub 2} immobilization through carbonate precipitation. Geochemical models are needed because alteration of the predominant host rock aluminosilicate minerals is very slow and is not amenable to laboratory experiment under ambient deep-aquifer conditions. Under conditions considered in our simulations, CO{sub 2} trapping by secondary carbonate minerals such as calcite (CaCO{sub 3}), dolomite (CaMg(CO{sub 3}){sub 2}), siderite (FeCO{sub 3}), and dawsonite (NaAlCO{sub 3}(OH){sub 2}) could occur in the presence of high pressure CO{sub 2}. Variations in precipitation of secondary carbonate minerals strongly depend on rock mineral composition and their kinetic reaction rates. Using the data presented in this paper, CO{sub 2} mineral-trapping capability after 10,000 years is comparable to CO{sub 2} dissolution in pore waters (2-5 kg CO{sub 2} per cubic meter of formation). Under favorable conditions such as increase of the Mg-bearing mineral clinochlore (Mg{sub 5}Al{sub 2}Si{sub 3}O{sub 10}(OH){sub 8}) abundance, the capacity can be larger (10 kg CO{sub 2} per cubic more » meter of formation) due to increase of dolomite precipitation. Carbon dioxide-induced rock mineral alteration and the addition of CO{sub 2} mass as secondary carbonates to the solid matrix results in decreases in porosity. A maximum 3% porosity decrease is obtained in our simulations. A small decrease in porosity may result in a significant decrease in permeability. The numerical simulations described here provide useful insight into sequestration mechanisms, and their controlling conditions and parameters. « less
Authors:
; ;
Publication Date:
OSTI Identifier:
801952
Report Number(s):
LBNL--50089
R&D Project: 468111; B& R KC0403010; TRN: US200223%%471
DOE Contract Number:
AC03-76SF00098
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 1 Apr 2002
Research Org:
Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
Sponsoring Org:
USDOE Director, Office of Science (US)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES; AQUIFERS; CARBONATE MINERALS; FLUID FLOW; REACTION KINETICS; SIMULATION; TRANSPORT; TRAPPING; US GULF COAST