Thomas Dewers 1 , Alex Rinehart 1 , Jon Major 2 , Photos placed in - - PowerPoint PPT Presentation

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Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND NO. 2011-XXXXP

GEOMECHANICS OF GEOLOGIC CARBON STORAGE: HAZARDS, LONG-TERM SEALING,

AND STORAGE SECURITY

Thomas Dewers1, Alex Rinehart1, Jon Major2, Peter Eichhubl2, Pania Newell1, Mario Martinez1, Joseph Bishop1, Steven Bryant2

1Sandia National Laboratories, Albuquerque

NM and 2University of Texas, Austin TX

SAND No. 2012-xxxxP

• Caprock Heterogeneity and Injection Response
• Time dependent growth of fractures in cap rock
• Heterogeneity and geomechanical response of subsurface reservoirs
• Chemo-mechanical coupling during injection
• Modeling of consequences of CO2 injection
• Parametric coupled flow and geomechanical analysis of

surface uplift

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CFSES Approach to GCS Geomechanics

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Tuscaloosa Sands @ 3km US National Energy Technology Laboratory Partnership Demonstration Projects

Core samples for geomechanical testing from NETL MGSC, SECARB, and SWP

Mt Simon Sandstone @ 2 km

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Heterogeneity and geomechanical response of subsurface reservoirs

Core, Well Logs and Sampling

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• Three well-log units (U, M, L)
• Three sampled lithofacies (I,

II, III)

• Similar porosities but

markedly different permeabilities

• Distribution of facies similar

to those on east flank of Illinois Basin (Saeed and Evans, 2012)

• Similar to lower portions of

Illinois Basin lithofacies (Bowen et al. 2011) incl. main injection horizon but lacking upper “B-cap” muddy facies Dewers et al., IJGHGC, Accepted

Lithofacies Interpretation

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I Lithofacies II Lithofacies III Lithofacies

• I Lithofacies (main injection unit in IB): quartz-rich sand flat B1 facies of

Saeed and Evans [2012] or the “sandy tidal” facies of Fischietto [2009]

• II Lithofacies: heterolithic T2 “mixed flat” facies and “sand flat to tidal

channel” B2 facies of Saeed and Evans [2012] or the “mixed fluvial-eolian tidal” and “braided fluvial” facies of Fischietto [2009]

• III Lithofacies: mud flat T1 facies of Saeed and Evans [2012] or the muddy

tidal facies of Fischietto [2009]

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Yield and Failure Envelopes

1 4 3 1 1

1 2

) ( I a e a a I F

I a f

  



) ( ) ( ) (

1 1 2

   I f I f J

c f

N I F I f

f f

  ) ( ) (

1 1

 

2 1 1 1 1 2

2 )) ( )( ( 1 ) , (             X I I I I fc (After Brannon et al., 2009; Pelessone, 1989)

Failure envelope: Yield Surface

Kayenta Model Validation

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• Non-Associative Plasticity
• Stress Invariant Dep. Failure
• Elliptical Cap Surface
• Kinematic Hardening
• Isotropic Hardening
• Nonlinear Elasticity
• Elastic-Plastic Coupling

Kayenta* Includes:

*Developed by Brannon et al. 2009

Dewers et al., IJGHGC, Accepted

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Modeling of consequences of CO2 Injection

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Martinez et al., IJGHGC, 2013

Coupled injection, multiphase flow, and geomechanics simulation showing range of over pressure and effective stress (top, at 5 yrs for 3 MT/yr) and CO2 saturation (bottom at 3 MT/yr (a), and 5 Mt/yr (b). Overpressure induced by higher injection rates results in opening of caprock fractures and leakage.

Overpressure, MPa, 5 Y at 3MT/Y Effective Stress, MPa, 5 Y at 3MT/Y CO2 Saturation, 5 Y at 3MT/Y CO2 Saturation, 5 Y at 5MT/Y

Application: Leakage Pathway Development in Jointed Caprock

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Application: Induced Seismicity In Mt Simon Sandstone

Person et al., Groundwater, 2013

Simulated pore pressure during injection, with failure occuring within gold shadied regions

Site of Youngstown Ohio 2011 earthquakes thought to be triggered by fluid injection into the Mt Simon

Locations of earthquake epicenters (circles) and injection wells for Guy, Arkansas 2010-2011 and Lake, Ohio 1983- 1986 earthquake swarms

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Application: Reservoir Drawdown and Wellbore Damage During CO2 Injection and Brine Withdrawal

Heath et al., ES&T, 2014

Map view of wellfield with injectors (triangles) and extractors (circles)

Drawdown at Mt Simon extraction wells can induce shear failure and wellbore damage

Threshold pressure for breakouts/well sanding determined experimentally

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Chemo-mechanical coupling during injection

14 Field and simulated pressure response at Cranfield injection zone (Kim and Hosseini, 2013)

• Pressure response during

injection suggests a “geomechanical event”

• Tracer studies show increase

in permeability with “event” Does chemistry of injectate influence geomechanical response?

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• Mixed chlorite- and quartz-

cemented muddy cross- bedded fine sandstone (Facies B);

• Quartz-cemented tabular very

fine sandstone (Facies C)

• Chlorite-cemented

conglomeratic sandstone (Facies A);

• T, P and major ion fluid

chemistry

• UCS, hydrostatic and

triaxial stress paths

• Pore fluid equilibrated

with scCO2 Lithofacies Geomechanical Testing Rinehart and Dewers, 2015

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• Accelerated creep at low stresses

consistent with stress corrosion model (pH-activated?)

• Failure of chlorite facies below in situ

stresses

• Grain-coating chlorite delamination (pH

activated?) Chemical effects may have caused “Geomechanical Event”

Degradation of elastic moduli masks the compactional- to-dilational turn-around in volume strain

Yield and Failure Surfaces

Facies A Facies B Facies C

In situ

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Untested

Post-70 MPa Test (Away From Fracture) Post-70 MPa Test (Near Fracture) Untested has chlorite cements, opaque grains, grain casts with remnant cements. Tests show pore collapse, grain shattering with increased intensity near fracture, and concentration of opaque grains and pore-filling clay minerals.

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Well-defined crystalline chlorite rims

Untested

Degraded chlorite rims without crystal habit

Post-70 MPa Test

• Exposure to CO2-equilibrated brine at 100°C overnight (24 hours)

influences chlorite cement crystallinity.

• Post-test photomicrograph is away from fracture feature, degradation

primarily a chemical effect but is pervasive through the sample.

• Other reservoir facies show enhanced creep but no substantial

degradation.

SolidWorks View of in situ short-rod fracture tester

WAVE SPRING SAMPLE LVDT ACTUATOR

Conclusions

• Sandstone reservoirs exhibit a range of heterogeneity and rock

mechanical responses to changing stress paths associated with

• injection. Weaker facies (e.g. Cenozoic sands in Gulf Coast &

Colorado Plateau, facies II and III for Mt Simon) exhibit elastic-plastic coupling.

• Chemo-mechanical effects – good (improved injectivity & sweep

efficiency) or bad (time-dependent leakage through caprock)?

• Validated Kayenta constitutive model captures essential features of

sandstone reservoir geomechanical behavior. It can be included in most FEM models.

• Experimental/Modeling approach for weak sandstone reservoirs

informs models on caprock leakage, induced seismicity, and wellbore

• damage. Can inform regulatory constrains on injectivity (i.e. frac

gradient) and withdrawal (borehole shear failure).

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