Modeling for Geologic Carbon Sequestration

Edward Mehnert, Ph.D. Illinois State Geological Survey

Prairie Research Institute University of Illinois at Urbana-Champaign

IEAGHG 2011 Summer School

July 18, 2011

Acknowledgments

The following colleagues provided valuable input for this presentation-- ◦ Prof. A. Valocchi, UIUC

◦ W.R. Roy, ISGS

◦ P.M. Berger, ISGS

◦ S. Frailey, ISGS

◦ R. Okwen, ISGS

◦ Q. Zhou, Lawrence Berkeley Nat’l Lab

◦ Y.-F. Lin, Illinois State Water Survey

Overview

Why modeling?

Define modeling

Types of modeling

Model characteristics

Modeling approaches

Examples

Available simulators

Bibliography

Why modeling?

Polled 100 scientists and engineers

Why do you model?

Why modeling?

To predict the effects of a future event (39)

To understand field data or observations (28)

To test/develop a scientific hypothesis (17)

To optimize a resource or process (13)

To develop a cost estimate (3)

Legal notice: Polling results supplied by M. Python Surveys & Other Nonsense, Ltd. These results are completely fictitious and

in no way reflect reality. No animals were harmed during polling.

Define modeling (Wikipedia)

Via modeling, scientists/engineers seek to represent empirical objects, phenomena, and physical processes in a logical and objective way.

All models are simplified reflections of reality, but, despite their inherent falsity, they are nevertheless extremely useful.

Building and disputing models is fundamental to the scientific process.

Types of modeling

Physical modeling ◦ Education

◦ Hypothesis testing

◦ Engineering design

Mathematical modeling

Numerical modeling

Types of modeling

Physical modeling ◦ Education– used by ISGS to demonstrate GCS

concepts at outreach mtgs

◦ Hypothesis testing

◦ Engineering design

Types of modeling

Physical modeling ◦ Education

◦ Hypothesis testing

◦ Engineering design

Direction of flow

Source: Zhang, C.Y., K. Dehoff, et al., 2010. Pore-Scale Study of Transverse Mixing Induced CaCO3 Precipitation and Permeability Reduction in a Model Subsurface Sedimentary System. Environmental Science & Technology 44(20): 7833-7838.

Model size: 2 cm long x 1 cm wide

Close-ups along centerline of mixing

model for 2 different saturation states.

Types of modeling

Physical modeling ◦ Education ◦ Hypothesis testing ◦ Engineering design– bridge design, Tanana River,

Alaska, study effects of woody debris on flow & scour

Top view– bridge pier in sand & gravel river bed

Side view– scour initiates on upstream side of bridge pier

Types of modeling

Types of modeling

Physical modeling

Mathematical modeling

Numerical modeling ◦ Want to know impact of nonuniform input data

◦ Need to understand effects of multiple processes

◦ Boundaries are too complex

◦ Choose finite difference, integral finite difference, or finite element methods

Model Characteristics

Dimensions– 1D, 2D, 2D-radial & 3D

Time– steady-state or transient

Processes– flow, transport, chemistry, heat, mechanics, economics, risk

Phases– 1, 2 or more

Assumptions

Solution techniques– analytical or numerical

Model Characteristics

Analytical Numerical

Dimensions 1D & 2D 1D, 2D & 3D

Processes Tends to be limited Flow only to cross-disciplinary

Assumptions Problematic at times (infinite aquifers?)

Modest

Effort & Time Hours to days Weeks to years

Input data required Limited Extensive

Technical expertise Math can be daunting (exotic math functions such as Kelvin or Bessel functions)

Parameter estimation & code experience key

Modeling Approaches

Traditional approach Data

acquisition

Analysis

Modeling

Results

Modeling Approaches

Traditional or step-wise modeling?

Data acquisition

Analysis

Modeling

Results

Analysis

Initial modeling

Modeling

Results

Data acquisition

Source: Haitjema, 1995

Geochemical Modeling-- motivation

Define the geochemical fate of CO2 and its effects on the injection formation and caprock or formation fluids. ◦ Will the porosity or permeability of the

injection formation be changed?

◦ How much or how fast is CO2 converted into carbonate phases?

Help Monitoring, Validation and Accounting programs to detect leaks.

Geochemical Modeling-- basics

Each model calculates the ion activity product and compares it to the equilibrium activity product (Kt) to estimate a saturation index (Ω).

Ω = log (ion activity product)/(Kt)

If Ω < 0, the solution is undersaturated wrt to that solid phase.

If Ω > 0, the solution is supersaturated

If Ω = 0, the solution is in equilibrium

Geochemical Modeling-- Limitations

Different models may yield different results because they are using different databases.

The quality of the databases varies with each solid phase.

The reliability of most models decreases with an increase in ionic strength.

The output must be interpreted carefully.

Geochemical Modeling– example 1

Brine from the IL Basin Decatur Project (MDT-5, depth= 6,840 feet or 2,085 m)

What is the brine’s saturation status?

Database Ionic strength

Ωcalcite Ωam silica

GWB React (thermo)

2.7 -0.59 -0.27

GWB React (Phrqpitz)

3.4 +0.03 No Si in model

PHREEQCi 4.1 -0.16 -0.28

Geochemical Modeling– example 2

General rate law, where: ◦ ∂m/∂t= change in mineral mass with time ◦ S= surface area ◦ ka= rate constant for acid- catalyzed reactions ◦ kn= rate constant at neutral pH conditions, ◦ Ω= saturation index, and a ◦ an

H+= activity of hydrogen raised to the nth power

Geochemical Modeling– example 2

Setup: CO2 injected into brine-saturated sandstone (pH= 6.8)

Predicted results ◦ Brine becomes acidic.

◦ Calcite buffered the system initially.

◦ Clay minerals acted as a long-term buffer.

◦ Some calcite precipitated after pH increases.

Jackson Sandstone

10 Illite + 1.23SiO2 + 7.75H+ ↔ 4H2O + 2.75K+ + 2.5Mg2+ + 10 Smectite

Geochemical Modeling– example 2

Predicted changes in mineralogy

Geochemical Modeling– example 2

Predicted change in porosity

Example: semi-analytical transport model to leakage

Assumptions ◦ Aquifers are

homogeneous, isotropic, horizontal, & infinite

◦ Aquitards are impermeable

◦ Flow thru segments of wells

◦ Sharp interface between brine & CO2

CO2 leakage in a developed basin, transient solution Series of papers by Celia, Noordbotten, Bachu & colleagues

Semi-analytical model for leakage

Solution provides a method to compute the position of the CO2 plume and the mass distribution of CO2 in the various aquifers as a function of time.

Assumptions • Each of aquifers and aquitards is homogeneous and isotropic, and has constant thickness and infinite horizontal extent

• Flow is horizontal in aquifers, and vertical in aquitards

• Flow through the leaky wells is laminar and governed by Poiseuille’s law (for open well bores) or Darcy’s law, and no storage in well bores.

Coupled Diffuse and Focused Brine Leakage in a Multilayered System with any Number of Injection and Leaky Wells (Cihan et al., 2011)

Example: GCS in an open basin

The Illinois Basin is open on the north side. Will the CO2 plume migrate out of the basin?

Use Hesse et al. (2008) 2D analytical solution to evaluate, assumptions include: ◦ aquifer has uniform slope & thickness, infinite extent, homogeneous K and porosity

◦ residual saturation is significant but dissolution is ignored (sharp interface)

◦ Vertical mixing (allows 2D solution)

Example: GCS in an open basin

2D Gravity current analysis– use to answer question about plume migration (Hesse et al., 2008)

Example: GCS in an open basin

Input Parameter (units) Best estimate

Saline aquifer thickness (m) 533 Aquifer permeability# (m2) 4.9x10-14

Relative permeability of the brine* 1.0 Relative permeability of the CO2* 0.2

Density difference between brine and CO2 (kg/m3) 400 Residual brine saturation* 0.2

Residual CO2 saturation* 0.2

Dip angle of the saline aquifer (degrees) 0.21 Viscosity of the brine (kgm/sec) 6.0x10-4

Viscosity of the CO2 (kgm/sec) 6.0x10-5

2D Gravity current analysis 10 wells arranged across 90 miles Total= 300 M tons/yr for 30 yrs (100% of CO2 emitted)

Results: ◦ maximum migration distance= 150 km or 94 miles ◦ Max migration time= 160,000 years

CO2 transport modeling example—TOUGH2-MP for IL Basin

Zhou et al. (2010)– estimate pressure increases and track CO2 plumes if GCS goes commercial in the Illinois Basin

Use TOUGH2-MP to evaluate two-phase flow Uses >1.2 million elements, runs on supercomputer Input needed: Lots! Detailed 3D mapping of geology & geologic and hydrogeologic

parameters for each layer.

CO2 transport modeling example—TOUGH2-MP for IL Basin results Location of CO2 plumes for two scenarios (low

and high injection rates) Plumes do not intersect, affected by structure in

Mt. Simon

CO2 transport modeling example—TOUGH2-MP for IL Basin results

Able to predict pressure in the Mt. Simon to evaluate potential effect of GCS

Simulators 1. MODFLOW (USGS, http://water.usgs.gov/nrp/gwsoftware/modflow.html)

2. MODFLOW GUIs: GW Vistas (www.groundwatermodels.com) & GMS (www.aquaveo.com)

3. MT3D (contam transport code for MODFLOW, http://www.sspa.com/software/mt3d.html)

4. Eclipse 2010 (Schlumberger, www.slb.com/services/software/reseng.aspx)

5. Landmark VIP (Halliburton, www.halliburton.com/ps/Default.aspx?navid=226&pageid=888&prodid=MSE%3a%3a1055451807810981)

6. TOUGH & TOUGHREACT (Lawrence Berkeley Nat’l Lab, http://esd.lbl.gov/TOUGH+/index.html)

7. NUFT (Lawrence Livermore National Lab, https://wci.llnl.gov/codes/cafda/nuft_c/)

8. STOMP (Pacific Northwest National Laboratory, http://stomp.pnnl.gov/)

9. PFLOTRAN (Los Alamos National Lab & other Labs, http://ees.lanl.gov/source/orgs/ees/pflotran/index.shtml)

10. GEM (CMG, www.cmgl.ca/software/gem.htm) 11. COMET3 (www.adv-res.com/comet3-nonconventional-resources.asp)

12. PHREEQC Interactive (USGS, pH-redox-equilibrium equations, http://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc/)

13. Geochemist’s Workbench (UIUC Dept of Geology, http://www.rockware.com/product/overview.php?id=132)

Bibliography Modeling

Anderson, M.P. and W.W. Woessner, 1992. Applied groundwater modeling: simulation of flow and advective transport, San Diego, Academic Press Inc., 381 p.

Chen, Z., G. Huan, and Y. Mia, 2006. Computational Methods for Multiphase Flows in Porous Media, Society for Industrial and Applied Mathematics, Philadelphia. (very heavy book -- petroleum engr related)

Haitjema, H.M., 1995. Analytic Element Modeling of Groundwater Flow. San Diego, Academic Press, Inc., 393 p.

Hornberger, G. and P. Wiberg, 2006. Numerical Methods in the Hydrological Sciences, AGU E-Book http://www.agu.org/cgi-bin/agubooks?book=SPSP057F251

Lemieux, J. M. 2011. Review: The potential impact of underground geological storage of carbon dioxide in deep saline aquifers on shallow groundwater resources, Hydrogeology Journal 19(4): 757-778.

Mercer, J.W. and C.R. Faust, 1980. Ground-water modeling: Mathematical models. Ground Water 18(2): 108-115.

Mercer, J.W. and C.R. Faust, 1980. Ground-water modeling: Mathematical models. Ground Water 18(3): 212-227.

Mercer, J.W. and C.R. Faust, 1980. Ground-water modeling: Applications. Ground Water 18(5): 486-497.

Pinder, G. and M. Celia, 2006. Subsurface Hydrology, Wiley Interscience (has a decent and readable section on multiphase flow)

Pruess, K., J. Garcia, et al., 2004. Code intercomparison builds confidence in numerical simulation models for geologic disposal Of CO2. Energy 29(9-10): 1431-1444.

USEPA, 2011. :Class VI Well site characterization guidance for owners and operators, EPA 816-D-10-006, http://water.epa.gov/type/groundwater/uic/class6/gsguidedoc.cfm

Wang, H.F. and M.P. Anderson, 1982. Introduction to Groundwater Modeling, W.H. Freeman, San Francisco.

Young, G.B.C., 1998. Computer modeling and simulation of coalbed methane resources, International Journal of Coal Geology 35(1-4): 369-379.

Zhou, Q.L., J.T. Birkholzer, et al., 2010. Modeling Basin- and Plume-Scale Processes of CO2 Storage for Full-Scale Deployment. Ground Water 48(4): 494-514.

Zheng, C. and G.D. Bennett, 2002. Applied Contaminant Transport Modeling, 2nd ed. J. Wiley & Sons., New York http://www.mt3d.org/

Bibliography Analytical solutions

For single-phase flow and well leakage:

Hemker, C.J., and C. Maas, 1987. Unsteady flow to wells in a layered and fissured aquifer systems, J. Hydrol., 90, 231-249. [for any number of aquifers and alternating aquitards, with diffuse water leakage through aquitards, without any leaky wells]

Nordbotten, J.M., Celia, M.A., and Bachu, S., 2004. Analytical solutions for leakage rates through abandoned wells, Water Resources Res. 40, W04204, doi:10.1029/2003WR002997.

[for focused well leakage for any number of aquifers/aquitards, and leaky wells, by assuming the aquitards are impervious]

Cihan, A., Q. Zhou, and J.T. Birkholzer, 2011. Generalized analytical solutions for pressure perturbation and leakage through aquitards and wells in a multilayered system, Water Resources Research [submitted, a new solution developed for any number of aquifers and alternating leaky aquitards, injection wells, and leaky wells, with both focused leakage through wells and diffuse leakage through aquitards]

For two-phase CO2-brine flow in the storage formation and leakage through wells. [for CO2 leakage through abandoned wells]

Nordbotten, J.M. and M.A. Celia, 2006. Similarity solutions for fluid injection into confined aquifers. Journal of Fluid Mechanics 561: 307-327. [for CO2 plume with any value of parameter gamma (high, and low injection rates)]

Nordbotten, J.M. and M.A. Celia, 2006. An improved analytical solution for interface upconing around a well. Water Resources Research 42(8).

Nordbotten, J.M., M.A. Celia, and S. Bachu, 2005. Injection and storage of CO2 in deep saline aquifers: Analytical solutions for CO2 plume evolution during injection, Transport in Porous media, 58, 339–360. => for CO2 plume for viscosity-dominant injection scenarios (large injection rate)

Celia, M.A., J.M. Nordbotten, et al., 2011. Field-scale application of a semi-analytical model for estimation of CO2 and brine leakage along old wells. International Journal of Greenhouse Gas Control 5(2): 257-269.

Hesse, M.A., F.M. Orr, et al., 2008. Gravity currents with residual trapping. Journal of Fluid Mechanics 611: 35-60.

Okwen, R.T., M.T. Stewart, et al., 2010. Analytical solution for estimating storage efficiency of geologic sequestration of CO2. International Journal of Greenhouse Gas Control 4(1): 102-107.

Bibliography Numerical simulators

Xu, T., N. Spycher, et al., 2011. TOUGHREACT Version 2.0: A simulator for subsurface reactive transport under non-isothermal multiphase flow conditions, Computers & Geosciences 37(6): 763-774.

Data sources

Palandri J.L. and Y.K. Kharaka, 2004. A Compilation of Rate Parameters of Water-mineral Interaction Kinetics for Application to Geochemical Modeling, U.S. Geological Survey Open File Report 2004-1068.

www.geochem-model.org

Geochemical Modeling

Allen, D. E., B.R. Strazisar, Y. Soong, and S.W. Hedges. 2005. Modeling carbon dioxide sequestration in saline aquifers: significance of elevated pressures and temperatures, Fuel Processing Technology, 86, 1569-1580.

Andre, L., P. Audigane, M. Azaroual, and A. Menjoz. 2007. Numerical modeling of fluid-rock chemical interactions at supercritical CO2-liquid interface during CO2 injection into a carbonate reservoir, the Dogger aquifer (Paris Basin, France). Energy Conversion and Management 48, 1782-1797.

Berger, P. M., W. R. Roy, and E. Mehnert. 2009. Geochemical modeling of carbon sequestration, MMV, and EOR. Energy Procedia, 1: 3437-3444.

Gaus, I., P. Audigane, L. Andre, J. Lions, N. Jacquemet, P. Durst, I. Czernichowski-Lauriol, and M. Azaroual. 2008. Geochemical and solute modelling for CO2 storage, what to expect from it? International Journal of Greenhouse Gas Control, 2, 605-625.

Gunter, W.D., B. Wiwchar, and E.H. Perkins, 1997. Aquifer disposal of CO2-rich greenhouse gases: extension of the time scale of experiment for CO2-seqestration reactions by geochemical modeling. Mineralogy and Petrology, 59, 121-140.

Gunter, W.D., E.H. Perkins, and I. Hutcheon. 2000. Aquifer disposal of acid gases: modeling of water-rock reactions for trapping acid wastes. Applied Geochemistry, 15, 1085-1095.

Knauss, K.G., J.W. Johnson, and C.I. Steefel. 2005. Evaluation of the impact of CO2, co-contaminant gas, aqueous fluid and reservoir rock interactions on the geologic sequestration of CO2. Chemical Geology, 217, 339-350.

Marini, L. 2007. Geological sequestration of carbon dioxide. Thermodynmics, kinetics, and reaction path modeling. Developments in Geochemistry 11, Elsevier, Amsterdam, The Netherlands.

Shiraki, R. and T. Dunn. 2000. Experimental study on water-rock interactions during CO2 flooding in the Tensleep Formation, Wyoming, USA. Applied Geochemistry, 15, 265-279.

Soong, Y., A.L. Goodman, J.R. McCarthy-Jones, and J.P. Baltrus. 2004. Experimental and simulation studies on mineral trapping of CO2 with brine. Energy Conversion and Management, 45, 1845-1859.