Sally Benson Presentation

6/9/11

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GLOBAL CLIMATE AND ENERGY PROJECT | STANFORD UNIVERSITY

Overview of Geologic CO2 Storage

Sally Benson Director, Global Climate and Energy Project

Stanford University

June 7, 2011

GLOBAL CHALLENGES – GLOBAL SOLUTIONS – GLOBAL OPPORTUNITIES

RECS 2011| Birmingham, Alabama

The Plan

1.  General overview of geological storage 2.  Why we think CO2 storage will work 3.  What does it take to do CO2 storage

safely 4.  What could go wrong and what we can

do about it

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Carbon Dioxide Capture and Geologic Storage

Capture Underground

Injection Pipeline

Transport Compression

Basic Concept of Geological Sequestration of CO2

•  Injected at depths of 1 km or deeper into rocks with tiny pore spaces

•  Primary trapping –  Beneath seals of low permeability rocks

Image courtesy of ISGS and MGSC Courtesy of John Bradshaw

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What Types of Rocks are Suitable for CO2 Storage?

•  Igneous rocks –  Rocks formed from cooling magma –  Examples

•  Granite •  Basalt

•  Metamorphic Rocks –  Rocks that have been subjected to high

pressures and temperatures after they are formed

–  Examples •  Schist •  Gneiss

•  Sedimentary rocks –  Rocks formed from compaction and

consolidation of rock fragments –  Example

•  Sandstone •  Shale

–  Rocks formed from precipitation from solution –  Example

•  Limestone

Granite

Schist

Sandstone

Crystalline Low porosity Low permeability Fractures


High porosity High permeability Few fractures

•  Igneous rocks –  Rocks formed from cooling magma –  Examples

•  Granite •  Basalt

•  Metamorphic Rocks –  Rocks that have been subjected to high

pressures and temperatures after they are formed

–  Examples •  Schist •  Gneiss

ü Sedimentary rocks –  Rocks formed from compaction and

consolidation of rock fragments –  Example

•  Sandstone •  Shale

–  Rocks formed from precipitation from solution –  Example

•  Limestone

Granite

Schist

Sandstone



High porosity High permeability Few fractures

What Types of Rocks are Suitable for CO2 Storage?

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X-ray Micro-tomography at the Advanced Light Source

Micro-tomography Beamline Image of Rock with CO2

Mineral grain

Water CO2

2 mm

8

Analysis of 3-D Images

Sand Grains

Water

CO2

Silin, Tomutsa, Benson and Patzek, 2010, Transport in Porous Media.

sw = 27% sw = 55%

1 mm

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Thermodynamic Properties of CO2

•  Important Properties – Phase (e.g. solid, gas, liquid, supercritical) – Density (kg/m3) – Viscosity (Pa-s)

•  Conditions – Storage reservoir – Leaks (shallower than the storage reservoir)

Typical Subsurface Temperature and Pressure Gradients

Temperature (oC)

0

500

1000

1500

2000

2500

3000

0 20 40 60 80 100

Dep

th (m

)

Pressure (bar)

0

500

1000

1500

2000

2500

3000

0 100 200 300 400

Dep

th (m

)

T = 10oC + 25oC/1,000 m x 1,250 m = 41.25oC

1,250 m

Ts=10oC

p= 105 Pa + 1,000 kg/m3 x 9.81 m/s2*1,250 m = 12.36 Mpa (123.6 bar)

1,250 m

Watertable = 0 m

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Pipeline Transportation

Phases of CO2 for CCS System

(31.0oC, 73.8 bar)

Leak in the atmosphere

Supercritical Fluid

1,600 m 1,250 m 900 m 500 m 200 m

CO2 Density

1,600 m 900 m

500 m 200 m

Water is 1.3 to 1.5 times denser than supercritical CO2 at these depths

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CO2 Viscosity

Water is 10 to 20 times more viscous than supercritical CO2 at these depths

1,600 m

900 m

500 m 200 m

High Density of Supercritical CO2 Defines Storage Depth

•  Storage below 800 m –  Supercritical CO2

–  Dense phase CO2 (500 to 800 kg/m3)

–  Low viscosity (0.04 to 0.06 cp)

•  Rule-of-thumb –  Depends on P and T

profile –  Will vary from site to site

•  Watertable depth •  Geothermal gradient •  Mean annual surface

temperature

Storage below 800 m

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Location of Deep Sedimentary Basins

IPCC, 2005 •  Three primary conditions –  Sedimentary rocks with storage reservoirs and seals –  Pressure and temperature > critical values (31oC, 78.3 bars) –  Not a source of drinking water

Example of A Cross Section of a Sedimentary Basin

Example of a sedimentary basin with alternating layers of coarse and fine textured sedimentary rocks.

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Specific Types of Formations Within Sedimentary Basins

•  Oil and gas reservoirs –  Enhanced oil and gas recovery –  Depleted oil and gas recovery

•  Deep rock formations that contain salt water (saline formations)

•  Coal beds

North American Sequestration Resources in Oil and Gas Reservoirs

Oil and gas reservoirs could potentially store about 60 years of current emissions from power generation.

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North American Sequestration Resources in Coal Beds

Unminable coal formations could potentially store about 80 years of current emissions from power generation.

North American Sequestration Resources in Saline Aquifers

Saline aquifers could potentially store more than 1,000 years of current emissions from power production.

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Global Sequestration Capacity Estimates

From KM13 GEA, 2011.

Expert Opinion about Storage Safety and Security

“ Observations from engineered and natural analogues as well as models suggest that the fraction retained in appropriately selected and managed geological reservoirs is very likely* to exceed 99% over 100 years and is likely** to exceed 99% over 1,000 years.” “ With appropriate site selection informed by available subsurface information, a monitoring program to detect problems, a regulatory system, and the appropriate use of remediation methods to stop or control CO2 releases if they arise, the local health, safety and environment risks of geological storage would be comparable to risks of current activities such as natural gas storage, EOR, and deep underground disposal of acid gas.”

* "Very likely" is a probability between 90 and 99%. ** Likely is a probability between 66 and 90%.

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Evidence to Support these Conclusions

•  Natural analogs –  Oil and gas reservoirs –  CO2 reservoirs

•  Performance of industrial analogs –  40+ years operating experience with

CO2 EOR in more than 100 projects –  100 years experience with natural

gas storage –  Acid gas disposal

•  30+ years of cumulative performance of actual CO2 storage projects –  Sleipner, off-shore Norway, 1996 –  Weyburn, Canada, 2000 –  In Salah, Algeria, 2004 –  Snohvit, Norway, 2008

~50 Mt/yr are injected for CO2-EOR

Natural Gas Storage

•  Seasonal storage to meet winter loads

•  Storage formations –  Depleted oil

and gas reservoirs

–  Aquifers –  Caverns

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Sleipner Project, North Sea

§ 1996 to present § 1 Mt CO2 injection/yr §  Seismic monitoring

Picture compliments of Statoil

Seismic Monitoring Data from Sleipner

From Chadwick et al., GHGT-9, 2008.

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Weyburn CO2-EOR and Storage Project

•  2000 to present •  1-2 Mt/year CO2 injection •  CO2 from the Dakota

Gasification Plant in the U.S.

Photo’s and map courtesy of PTRC and Encana

In Salah Gas Project

In Salah Gas Project - Krechba, Algeria

Gas Purification - Amine Extraction

0.6 Mt/year CO2 Injection Operations Commence

- June, 2004

Gas Processing and CO2 Separation Facility

Courtesy of BP

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Snohvit, Norway

•  Snohvit Liquefied Natural Gas Project (LNG) –  Barents Sea, Norway

•  Gas Purification (removal of 5-8% CO2) –  Amine Extraction

•  0.7 Mt/year CO2 Injection –  Saline aquifer at a depth of 2,600 m (8530 ft) below sea-bed

•  Sub-sea injection •  Operations Commence

–  April, 2008

Courtesy StatoilHydro

Key Elements of a Geological Storage Safety and Security Strategy

Regulatory Oversight

Remediation

Monitoring

Safe Operations

Storage Engineering

Site Characterization and Selection

Fundamental Storage and Leakage Mechanisms

Financial Responsibility “… the fraction retained is

likely to exceed 99% over 1,000 years.”

“ With appropriate site selection informed by available subsurface information, a monitoring program to detect problems, a regulatory system, and the appropriate use of remediation methods…”

IPCC, 2005

“… risks similar to existing activities such as natural gas storage and EOR.”

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Remediation

Monitoring

Safe Operations

Storage Engineering






IPCC, 2005


Fundamental Storage Mechanisms

•  Injected at depths of 1 km or deeper into rocks with tiny pore spaces

•  Primary trapping –  Beneath seals of low permeability rocks with

high capillary entry pressures

•  Secondary trapping –  CO2 dissolves in water –  CO2 is trapped by capillary forces –  CO2 converts to solid minerals –  CO2 adsorbs to coal

Image courtesy of ISGS and MGSC

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Seal Rocks and Mechanisms

•  Shale, clay, and carbonates

•  Permeability barriers to CO2 migration

•  Capillary barriers to CO2 migration

Cappilary Barrier Effectiveness

1

10

100

1000

Delta PlainShales

ChannelAbandonment

Silts

Pro-DeltaShales

Delta FrontShales

ShelfCarbonates

Entry

Pre

ssur

e (B

ars)

Increasing Effectiveness

1.E-19

1.E-16

1.E-13

1.E-10

1.E-07

Gravel CourseSand

Siltysands

Clayeysands

Clay Shale

Perm

eabl

ity (m

2 )

Capillary Barrier Effectiveness

Multiphase Flow of CO2 and Brine

Waare C Sandstone

Berea Sandstone

Influence of Heterogeneity

Influence of Buoyancy

•  What fraction of the pore space will be occupied?

•  What will be the footprint of the plume? •  How much dissolution and capillary

trapping can be expected? Relative Permeability

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Secondary Trapping Mechanisms Increase Over Time



Remediation

Monitoring

Safe Operations

Storage Engineering






IPCC, 2005


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Site Characterization and Site Selection

•  Oil and gas reservoirs –  Current and future abandoned

wells –  Geomechanical impacts to seal –  Capacity

•  Saline formations –  Seal adequacy over ~ 100 km2

•  Closed trap vs. open trap –  Injectivity –  Capacity –  Plume size –  Pressure buildup

•  Coal beds –  Injectivity –  Containment

•  Adsorption •  Seals •  Hydraulic fractures

Current Approach for Assessing Capacity in Saline Aquifers

Geology

Models

Simulations Statistics

CO2 Storage Capacity = 1 to 5% Total Pore Volume1 Probability

Distributions

1 North American Carbon Sequestration Atlas, 2011

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Remediation

Monitoring

Safe Operations

Storage Engineering






IPCC, 2005


Storage Security: Long Term Risk Profile

Injection begins

Injection stops

2 x injection period


n x injection period

Monitor

Model

Calibrate &

Validate Models

Calibrate &

Validate Models

Hea

lth S

afet

y an

d

Env

ironm

enta

l Ris

k

Acceptable Risk

Site selection Active and abandoned well completions Storage engineering

Pressure recovery Secondary trapping mechanisms Confidence in predictive models

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Storage Engineering

Injection begins

Injection stops



n x injection period

Hea

lth S

afet

y an

d

Env

ironm

enta

l Ris

k

Acceptable Risk

Improved storage engineering Higher quality well completions Plume containment

Improved understanding of trapping Accelerated trapping

Site selection Monitoring High quality well completions



Remediation

Monitoring

Safe Operations

Storage Engineering






IPCC, 2005


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What Could Go Wrong?

Potential Consequences (rank ordered by impact) 1.  Worker safety

2.  Groundwater quality degradation

3.  Resource damage

4.  Ecosystem degradation

5.  Public safety 6.  Structural damage

7.  Release to atmosphere

•  Well leakage (injection and abandoned

wells) •  Poor site characterization (undetected

faults) •  Excessive pressure buildup damages seal

Potential Release Pathways

World Map of Active and Abandoned Wells



Remediation

Monitoring

Safe Operations

Storage Engineering






IPCC, 2005


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Seismic Monitoring Data from Sleipner Monitoring Methods

Cross-Well Seismic Active Source Thermal Sensors

Pressure Transducer

Pressure Transducer

Injection Well

Flux Accumulation Chamber

Flux Tower

Injection Rate Wellhead Pressure Annulus Pressure Casing Logs CO2 Sensors

Monitoring Well

Walk Away VSP

3-D Seismic

Seismic Monitoring

Surface Seismic 2-D, 3-D, and 4D

CO2

Vertical Seismic Profile (VSP) Cross-Well Tomography

Well

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Plume and topmost layer 2001 - 2006

From Andy Chadwick, BGS, 2010

Surface Monitoring

Detection Verification Facility (Montana State University)

80 m

Flow Controllers

Field Site

Horizontal Injection Well

Flux Tower

Soil Gas

Hyperspectral Imaging of Vegetation

Flux accumulation chamber

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How Do You Find a Leak?

Willow Creek

-2000

-1000

0

1000

2000

3000

0 60 120 180 240 300 360

Time (days)

µg/

m2 /s

Courtesy of Ken Davis and Paul Bolstad

Large Plume Footprint

~ 100 km2

Large Fluctuations in Background CO2 Fluxes

Small Leakage Footprint < 1 km2 ?

CO2 and 13C Isotopes Anomalies for Monitoring Leakage

High precision isotopic 13C analyzer: Picarro Instruments cavity ring down

spectrometer

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Raw 12CO2 and 13CO2 Data

Krevor et al., 2010, International Journal of Greenhouse Gas Control Technology

Source Term Characterization Leak Rate = 200 kg/day (73 tonnes/year!)

From Krevor et al., 2010, International Journal of Greenhouse Gas Control Technology

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Scaling Up Isotopic Monitoring



Remediation

Monitoring

Safe Operations

Storage Engineering






IPCC, 2005


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Remediation Options: Groundwater

•  Passive methods –  Natural attenuation by dissolution,

migration, and mineralization

•  Active methods –  Gas phase pumping –  Groundwater extraction to dissolve plume –  Single well dissolution system: inject and produce water

Picture taken from http://www.clu-in.org/download/remed/542r01021b.pdf

•  Methods to deal with other contamination due to dissolution of minerals by CO2 –  Pump and treat wells –  Containment by managing hydraulic

heads –  Treatment walls

Evaluation of Three Scenarios

Simulations by Ariel Esposito, Stanford University

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Extraction Remediation Scenarios

Simulations by Ariel Esposito, Stanford University



Remediation

Monitoring

Safe Operations

Storage Engineering






IPCC, 2005


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Institutional Issues

•  Regulations for storage: siting, monitoring, performance specifications

•  Financial responsibility for for long term stewardship •  Legal framework for access to underground pore space •  Carbon trading credits for CCS •  Clean Development Mechanism (CDM) credits for CCS •  Public acceptance

None is likely to be a show stopper, but all require effort to resolve.

Maturity of CCS Technology

•  Are we ready for CCS?

Oil and gas reservoirs

Saline aquifers

Coalbeds

State-of-the-art is well developed, scientific understanding is excellent and engineering methods are mature

Sufficient knowledge is available but practical experience is lacking, economics may be sub-optimal, scientific understanding is good

Demonstration projects are needed to advance the state-of-the art for commercial scale projects, scientific understanding is limited

Pilot projects are needed to provide proof-of-concept, scientific understanding is immature

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Worldwide CCS Projects

Concluding Remarks

•  CCS is an important part of the portfolio of technologies for reducing greenhouse gas emissions

•  Progress on CCS proceeding on all fronts –  Industrial-scale projects –  Demonstration plants –  R&D

•  Technology is sufficiently mature for large scale demonstration projects and commercial projects with CO2-EOR

•  Research is needed to support deployment at scale •  Institutional issues need to be resolved to support

widespread deployment

Documents

Sally Benson Presentation