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

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:OSTI ID: 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