Mineral sequestration of carbon dioxide in a sandstone–shale system
Introduction
A possible means of reducing carbon dioxide (CO2) emissions to the atmosphere is injection of CO2 into structural reservoirs in deep permeable geologic formations (Holloway, 1997). Such formations could include aquifers, oil and gas fields, and coal seams. Aquifers are the most abundant fluid reservoirs in the subsurface. The deepest aquifers in the United States commonly contain brackish or saline water. Aquifers with salinities exceeding 10,000 mg/L total dissolved solids are excluded by the U.S. Environmental Protection Agency as underground sources of drinking water. Hence, they are logical targets for the eventual disposal of CO2. The feasibility of storing CO2 in aquifers has been discussed in the technical literature over the last decade. These include an evaluation of the feasibility of CO2 aquifer storage in The Netherlands (Lohuis, 1993) and in the Alberta Basin, Canada (Gunter et al., 1993, Bachu et al., 1994, Perkins and Gunter, 1995, Law and Bachu, 1996, Gunter et al., 1996, Gunter et al., 1997). Furthermore, large-scale CO2 disposal in an aquifer is already being practiced in the Norwegian sector of the North Sea (Korbol and Kaddour, 1995). Recently, extensive experimental, field, and modeling studies of geological carbon sequestration have been conducted (Pearce et al., 1996, Rochelle et al., 1996, Gunter et al., 1997, Ortoleva et al., 1998, Johnson et al., 2001, White et al., 2001, McPherson and Lichtner, 2001, Oelkers et al., 2002, Rosenbauer and Koksalan, 2002, Kaszuba et al., 2002, Boram et al., 2002, Matter et al., 2002, Giammar et al., 2002, Jones et al., 2002, Goodman et al., 2002, Hedges et al., 2002, Hovorka et al., 2002, Horita, 2002, Knauss et al., 2002, Solano-Acosta et al., 2002, Palandri and Kharaka, 2002, Strazisar and Zhu, 2002, Perkins et al., 2002, Pruess et al., 2003).
Numerical modeling of geochemical processes is necessary to investigate long-term CO2 injection in deep aquifers, because aluminosilicate mineral alteration is very slow under ambient deep-aquifer conditions and is not amenable to experimental study. Xu et al. (2004) present a geochemical modeling analysis of the interaction of aqueous solutions under high CO2 partial pressures with three different rock types. The first rock is a glauconitic sandstone from the Alberta Sedimentary Basin. The second rock type evaluated is a proxy for a sediment from the United States Gulf Coast. The third rock type is a dunite, an essentially monomineralic rock consisting of olivine.
Xu et al. (2003) performed reactive transport simulations of a 1-D radial well region under CO2 injection conditions in order to analyze CO2 immobilization through carbonate precipitation, using Gulf Coast sandstones of the Frio formation of Texas. Most of the simulated mineral alteration pattern is consistent with the observations. Some inconsistencies with field observations are noted. For example, quartz abundance declines over the course of the simulation, while quartz overgrowths are observed during diagenesis due to the release of SiO2 during replacement of smectite by illite in adjacent shales (Land, 1984). The formation of pyrite in the field is not reproduced by the previous simulation, because sulfur (S) was not included in the kerogen composition.
The previous modeling (Xu et al., 2003, Xu et al., 2004) was simplified and approximated many of the complexities of actual diagenesis in the field. Major simplifications and limitations include, (1) treating the sandstone aquifer as if it were a closed system isolated from the enclosing shales, and (2) not adequately representing the extremely complex process of kerogen decomposition (or petroleum maturation) in deeply buried sediments. The proportions of reactant minerals in the simulation therefore differ from that of the total system in the field. The long-term interaction of injected carbon dioxide into sandstone aquifers with shale confining layers has not yet been investigated.
Here we present simulation results on mass transfer, mineral alteration, and consequent CO2 sequestration by carbonate precipitation in a sandstone–shale system. The mineral compositions of sandstone and shale were taken from Gulf Coast sediments. The mineralogy, thermodynamic database and kinetic data are refined from previous studies (Xu et al., 2003, Xu et al., 2004).
Section snippets
Simulation method
The present simulations were carried out using the non-isothermal reactive geochemical transport code TOUGHREACT (Xu and Pruess, 1998, Xu and Pruess, 2001). This code was developed by introducing reactive chemistry into the framework of the existing multi-phase fluid and heat flow code TOUGH2 (Pruess et al., 1999). Our modeling of flow and transport in geologic media is based on space discretization by means of integral finite differences (Narasimhan and Witherspoon, 1976). An implicit
Sandstone–shale configuration and properties
Much specific and detailed information will be required to assess the feasibility of disposing of CO2 in a sandstone–shale formation at any particular site, and to develop engineering designs for CO2 disposal systems. Before moving into site-specific investigations, general features and issues relating to the formation injection of CO2 should be explored. This can be done by investigating a sandstone–shale system that abstracts site-specific features representing characteristics that are common
Base case
Concentrations of aqueous chemical components through the sandstone–shale transect are presented in Fig. 2. To track diffusive transport fronts, a non-reactive tracer concentration of 1 was applied initially to the sandstone grid block. Fig. 2a shows tracer concentration distribution at different times. The initial pH in the sandstone is 7.34, and that in shale is 6.69. The imposition of a high CO2 pressure of 201 bar lowers the pH in the sandstone (Fig. 2b), and H+ diffuses from the sandstone
Summary and conclusions
A reactive geochemical transport model for a sandstone–shale system under high CO2 pressure conditions has been developed. The model has been used to analyze mass transfer of aqueous chemical components, the alteration pattern of minerals, sequestration of CO2 by secondary carbonates, and changes of porosity for a Gulf Coast aquifer.
CO2 diffuses from the sandstone (where CO2 is initially injected), lowering pH. Fe+2 from chlorite dissolution and Ca+2 from oligoclase dissolution diffuses from
Acknowledgement
We thank Curtis Oldenburg and Guoxiang Zhang for the internal reviews of the manuscript. We acknowledge Jacques Schott, Sigurdur Reynir Gislason, and two anonymous reviewers for their detailed helpful suggestions and comments during the review process that significantly improved the quality of the paper. This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy, under Contract No. DE-AC03-76SF00098 with Lawrence Berkeley
References (95)
- et al.
Aquifer disposal of CO2: hydrodynamic and mineral trapping
Energy Convers. Manag.
(1994) - et al.
Comparative study of the kinetics and mechanisms of dissolution of carbonate minerals
Chem. Geol.
(1989) - et al.
An experimental study of dolomite dissolution rates as a function of pH from −0.5 to 5 and temperature from 25 to 80 °C
Chem. Geol.
(1999) - et al.
Aquifer disposal of CO2-rich gases: reaction design for added capacity
Energy Convers. Manag.
(1993) - et al.
Technical and economic feasibility of CO2 disposal in aquifers within the Alberta Sedimentary Basin, Canada
Energy Convers. Manag.
(1996) - et al.
Calculation of the standard molal thermodynamic properties of crystalline, liquid, and gas organic molecules at high temperatures and pressures
Geochim. Cosmochim. Acta
(1998) - et al.
SUPCRT92: a software package for calculating the standard molal thermodynamic properties of minerals, gases, aqueous species, and reactions from 1 to 5000 bars and 0 to 1000 degrees C
Comput. Geosci.
(1992) - et al.
Sleipner vest CO2 disposal-injection of removed CO2 into the Utsira Formation
Energy Convers. Manag.
(1995) - et al.
Hydrogeological and numerical analysis of CO2 disposal in deep aquifers in the Alberta Sedimentary Basin
Energy Convers. Manag.
(1996) - et al.
The dissolution of biotite and chlorite at 25 °C in the near-neutral pH region
Contam. Hydrol.
(1996)
Natural occurrences as analogues for the geological disposal of carbon dioxide
Energy Convers. Manag.
Modelling chemical equilibria of acid mine drainage: the FeSO4–H2SO4–H2O system
Geochim. Cosmochim. Acta
Calculation of multicomponent chemical equilibria and reaction processes in systems involving minerals, gases and aqueous phase
Geochim. Cosmochim. Acta
Calculation of the thermodynamic properties at elevated temperatures and pressures of saturated and aromatic high molecular weight and liquid hydrocarbons in kerogen, bitumen, petroleum and other organic matter of biogeochemical interest
Geochim. Cosmochim. Acta
Quartz solubility at low temperatures
Geochim. Cosmochim. Acta
Inorganic species in geologic fluids, correlations among standard molal thermodynamic properties of aqueous ions and hydroxide complexes
Geochim. Cosmochim. Acta
A new kinetic approach to modeling water–rock interaction: the role of nucleation, precursors and Ostwald ripening
Geochim. Cosmochim. Acta
Correlating quartz dissolution kinetics in pure water from 25° to 625 °C
Geochim. Cosmochim. Acta
Numerical simulation to study mineral trapping for CO2 disposal in deep aquifers
Appl. Geochem.
Geochemical modeling of steady state and chemical reaction during supergene enrichment of porphyry copper deposits
Econ. Geol.
Assessment of feldspar solubility constants in water in the range 0° to 350 °C at vapor saturation pressures
Am. J. Sci.
Diagenesis and reservoir quality of the Aldebaran Sandstone, Denison Trough, east-central Queensland, Australia
Sedimentology
Postdepositional history of the Permian Sequence in the Denison Trough, eastern Australia
Am. Assoc. Petrol. Geol. Bull.
Continental-scale magmatic carbon dioxide seepage recorded by dawsonite in the Bowen-Gunnedah-Sydney Basin system, eastern Australia
J. Sed. Res.
Feldspar dissolution kinetics, Chapter 7 of chemical weathering rates of silicate minerals
Plagioclase dissolution and carbonate growth related to CO2 sequestration in deep aquifers: EQ3/6 modeling and laboratory experiments
Methanol: heat capacity, enthalpies of transition and melting, and thermodynamic properties from 5–300 K
J. Chem. Phys.
Synthesis, characterization, and energetics of solid solution along the dolomite–ankerite join, and implications for the stability of ordered CaFe(CO3)2
Am. Mineral.
The interrelation between gas and oil relative permeabilities
Prod. Mon.
Petrology of sedimentary rocks
Silicate weathering at pressure, temperature, and aqueous carbon dioxide conditions relevant to geologic carbon sequestration
Methanethiol and carbon disulfide: heats of combustion and formation by rotating-bomb calorimetry
J. Phys. Chem.
Carbon dioxide sequestration with brines
Aquifer disposal of CO2-rich greenhouse gases: extension of the time scale of experiment for CO2-sequestering reactions by geochemical modeling
Mineral. Petrol.
Experimental investigation of gas/water/rock interactions relevant to geological CO2 sequestration
Summary and critique of the thermodynamic properties of minerals
Am. J. Sci.
Theoretical prediction of the thermodynamic behavior of aqueous electrolytes at high pressures and temperatures: IV. Calculation of activity coefficients, osmotic coefficients, and apparent molal and standard and relative partial molal properties to 600 °C and 5 kb
Am. J. Sci.
Changes in the molecular structure of a Type II-S kerogen (Monterey Formation, U.S.A.) during sequential chemical degradation
Org. Geochem.
In internally consistent thermodynamic data set for phases of petrological interest
J. Metamorph. Geol.
An overview of the underground disposal of carbon dioxide
Energy Convers. Manag.
Profilometer-based study of nanometer- to millimeter-scale growth kinetics of calcite from CO2-rich fluids
Sequestration pilot site in the Texas Gulf coast, USA
Porosimetry measurement of shale fabric and its relationship to illite/smectite diagenesis
Clays Clay Miner.
Mechanism of burial metamorphism of argillaceous sediment: I. Mineralogical and chemical evidence
GSA Bull.
Reactive transport modeling of geologic CO2 sequestration in saline aquifers: the influence of intra-aquifer shales and the relative effectiveness of structural, solubility, and mineral trapping during prograde and retrograde sequestration
Cited by (467)
Two-dimensional modeling of CO<inf>2</inf> storage in high heat flow areas: Insights from the Las Tres Virgenes geothermal field, Mexico
2024, International Journal of Greenhouse Gas ControlTracing the evolution and charting the future of geothermal energy research and development
2023, Renewable and Sustainable Energy Reviews