Transcript Slide 1

Carbon Capture & Storage
A Technical Overview
Rosalind Parke
Principal Advisor, RPS Energy
Carbon Capture Legal Programme, 16th June 2008
The Carbon Cycle
• Carbon dioxide is a naturally
occurring gas under normal
atmospheric conditions
• It is necessary for life and is
exchanged, absorbed and
Photosynthesis
emitted via a complex,
interwoven series of processes
• In the past, the natural
processes stabilised CO2
levels in the atmosphere
• Human influence has thrown
out this balance
CCS Technical Overview - CCLP June 16 2008
Respiration,
Decomposition
& Deforestation
Re-vegetation
Diffusion
Combustion &
Industrial
Processes
Definition
Geological Carbon Capture and Storage is
“The active separation and capture of CO2 from the
atmospheric emissions of industrial processes and the
transport and permanent disposal of the CO2 in deep
underground rock formations”
• It does not refer to the biological removal and sequestration
of CO2 from the atmosphere into natural sinks, such as land
use, forestry or oceans
CCS Technical Overview - CCLP June 16 2008
“CO2 injection is new, isn’t it?”
Not quite….
• Underground injection of natural gas for short-term storage has
been in operation for almost 100 years
• CO2 Enhanced Oil Recovery (EOR) first applied in Scurry County,
Texas in 1972 and has successfully been used throughout the
Permian Basin; > 70 active EOR projects
• Weyburn EOR project (2000) in Saskatchewan has CO2 piped 204
miles from North Dakota, injecting 1-2MtCO2 pa
• GdF’s pilot EGR project at K12B, Netherlands (2004) aims to inject
8MtCO2 over the lifetime of the project
• Historically, projects driven by production economics
CCS Technical Overview - CCLP June 16 2008
Global View
Source: IPCC Special Report, 2005
CCS Technical Overview - CCLP June 16 2008
Storage Projects
• Statoil’s Sleipner project in the North Sea (1996) strips the CO2
(~9%) from gas production and injects it at 1MtCO2 pa into a deep
saline formation
• BP/Sonatrach/Statoil’s In-Salah project in Algeria (2004) similarly
strips CO2 and re-injects into the water-filled part of the gas
reservoir
• StatoilHydro started injection into the Snohvit offshore producing
natural gas reservoir in April 2008, goal 0.7 MtCO2 pa
• Pilot storage projects also operational at Frio-Texas, Otway BasinAustralia and Nagaoka-Japan
CCS Technical Overview - CCLP June 16 2008
So what’s the big deal?
• Transition
– Existing projects driven by low incremental cost
– Future roll-out to heavy industry and power generation requires significant
investment, infrastructure development and technical evolution
– Purity of CO2 has implications
• Scaling up
– IEA estimates 6Gt CO2 pa could be captured and stored by 20501
– 6000 Sleipner projects
– Implications for resources, co-ordination and delivery
• Verification
– Lack of monitoring of historic EOR projects provides little quantifiable data
on storage and effectiveness
Notes:
1. IEA June 2006, Energy Technology Perspectives Scenarios and Strategies
CCS Technical Overview - CCLP June 16 2008
Framework for Action
Site
Identification
Capture
Transportation
Injection &
Storage
Planning and Consents
Regulatory/ Policy Framework
Market Incentives
CCS Technical Overview - CCLP June 16 2008
Monitoring
Framework for Action
Site
Identification
Capture
Transportation
Injection &
Storage
Planning and Consents
Regulatory/ Policy Framework
Market Incentives
CCS Technical Overview - CCLP June 16 2008
Monitoring
Storage Evaluation
• Various geological formations can be utilised - depleted oil
and gas reservoirs, coal formations, saline aquifers
• Detailed modelling required to assess suitability for storage
– Sediment type, porosity, thickness and permeability
– Basin location, tectonic activity
– Geothermal gradients
– Hydrodynamics
– Geomechanics and geochemistry
– Structural simplicity
– Uniformity of cap rock
– Prior hydrocarbons production and legacy
CCS Technical Overview - CCLP June 16 2008
Framework for Action
Site
Identification
Capture
Transportation
Injection &
Storage
Planning and Consents
Regulatory/ Policy Framework
Market Incentives
CCS Technical Overview - CCLP June 16 2008
Monitoring
Capture Options
Post-Combustion
•
•
Applied in industrial processes
where flue gas streams often
>90% CO2; vented
–
coal-fired power plant
10-12% CO2
natural gas combined cycle
plants 3-6% CO2
Fuel is gasified to form H2 and
CO, which converts to CO2
•
Combustion takes place in an
enriched oxygen environment
•
CO2 concentrations are high,
15-80% dependent on fuel, and
high pressure
•
Highly concentrated flue gas,
>80% CO2
•
Incremental energy penalty higher,
8-30%
•
Current design configuration and
materials cannot operate at the
higher flame temperature
•
•
Impurities and total volumes
processed reduce effectiveness
•
Compressing CO2 to pipeline
pressure represents a large
parasitic load (10-30%)
•
However, technology well
understood and can be retrofitted
OxyFuel Combustion or Zero Emission
•
In comparison
–
•
Pre-Combustion or Syngas Approach
CCS Technical Overview - CCLP June 16 2008
Efficient separation, lower
incremental energy penalties
(<10%)
IGCC technology proven, but
costly and new build; not suited to
lower rank coals
–
Flue gas recirculation may
mitigate and allow specific
retrofit
Framework for Action
Site
Identification
Capture
Transportation
Injection &
Storage
Planning and Consents
Regulatory/ Policy Framework
Market Incentives
CCS Technical Overview - CCLP June 16 2008
Monitoring
Transportation
•
Transporting CO2 is an established practice, with
over 3000 miles CO2 pipeline in US alone
–
Construction and costs similar to natural gas
–
Distance to storage drives unit costs
•
Principle issue is not R&D, but likely obstacles in
siting new networks for increased scale
•
Shipping provides an alternative
–
Similar technology as LPG/LNG transportation;
small semi pressurised vessels in operation
–
Relatively new application, requires R&D
–
Investment not purely in ships;
liquefaction, intermediate storage and
loading/unloading facilities also required;
CCS Technical Overview - CCLP June 16 2008
–
CAPEX&OPEX trade off against pipeline
–
In theory, more attractive over longer distances
Framework for Action
Site
Identification
Capture
Transportation
Injection &
Storage
Planning and Consents
Regulatory/ Policy Framework
Market Incentives
CCS Technical Overview - CCLP June 16 2008
Monitoring
Injection Methodology
•
Injection is targeted below 0.8km since
the formation pressure at this depth will
maintain the supercritical fluid form
–
•
In this phase, the CO2 occupies less
volume and can diffuse through
formation pore spaces like a gas
Injection influenced by storage character
–
Injecting cold dense CO2 into lower
pressure environments has implications
for phase transformation such as solid
hydrate formation
–
Temperature differentials are important
from the perspective of modelling
potential for thermal fracturing of the
reservoir
CCS Technical Overview - CCLP June 16 2008
Injection Facilities
•
A CO2 injection well is similar to a typical gas injection well except that downhole
components have higher pressure ratings and corrosion resistance
–
•
Production or injection wells in depleted oil/gas fields are often reused as CO2
injection wells, with certain restrictions
–
–
–
–
•
Acid gas disposal and CO2-EOR have produced significant experience
Materials such as cement and tubing may require upgrading
Injection zones isolated to desired CO2 target
Additional safety valves installed to mitigate against blowout
Importantly, as fields near depletion and decommissioning, the window for re-utilising
existing facilities narrows
The number of wells required depends on many factors, including
–
–
–
–
Total injection rate
Permeability and thickness of the formation
Maximum injection pressure
Land availability
CCS Technical Overview - CCLP June 16 2008
Trapping over Time
•
Physical traps
–
Stratigraphic
•
•
–
Structural
•
•
–
tectonic influences bend/fracture rock layers
may be a simple dome, a "crease" in the rocks, or a more
complex fault trap
Residual
•
•
depositional in nature, trap forms as layering switches
permeability e.g. sandstone to shale
primary seal provided by dense overlayer of impermeable cap
rock
post-injection, water moves back into the porous formation,
increases capillary pressure on CO2
Geochemical trapping
–
Solubility
•
–
Mineral Trapping
•
•
CO2 dissolves in formation water, eliminating buoyancy
Some of the dissolved carbonic acid precipitates out stable
carbonates if appropriate mineralogy present in the formation
Ideally, physical and chemical trapping mechanisms interact over time
CCS Technical Overview - CCLP June 16 2008
Storage Security
• CO2 release scenarios
–
–
–
–
–
–
Ineffective cap rock
Leakage across faults
Leaking injection wells
Abandoned wells
Aquifer flow/diffusion
Thermal fracture
Sequestration
Field A
Seabed
Remote
Field C
Sequestration
Field B
Sea current
Old pockmark
“Wytch hole”
Leak off
Diffusion
Escape to
surface via
aquifer outflow
WAG allows
Aquifer flow
through trapped
gas
Accumulations
In mud
Over pressurise
shallower formation
WAG
OWC tilt
Well plug
Abandoned
well
Pressure
induced
fracture
Diffusion
& flow
Mineralisation
Free
gas P, T
GSGI
Aquifer
flow at shallower
depths
Cap good
for oil but
not gas
Shale
Diffusion
Aquifer flow
Dispersive
mixing
Shale
• Comprehensive initial assessment should model potential risks
and identify mitigation strategies
CCS Technical Overview - CCLP June 16 2008
Framework for Action
Site
Identification
Capture
Transportation
Injection &
Storage
Planning and Consents
Regulatory/ Policy Framework
Market Incentives
CCS Technical Overview - CCLP June 16 2008
Monitoring
Monitoring Strategy
• Monitoring applies throughout the project lifetime
– Prior to injection
• Baseline studies are made for future reference against chemical/structural
changes
– During injection
• Repeated 3D-seismic monitoring refines the model of CO2 distribution and
inputs to ongoing injection operations (pressure/ well locations)
• Well conditions observed for deterioration
• Injection rates recorded
– Post-injection
• Verify CO2 remains contained/ alert to any signs of leakage
• There are currently no defined monitoring guidelines either for
techniques or timeframes
– IEA Weyburn-Midale, Sleipner, Otway, CO2SINK and CO2ReMoVe
projects should all provide necessary experience, if disseminated
CCS Technical Overview - CCLP June 16 2008
In Summary
• Carbon Capture and Storage projects are hugely complex
technical projects requiring immense experience across a
broad range of skills
• R&D is still required to transition this to large scale, multiple
source application
• Evolution of market and regulatory frameworks will provide
the necessary incentives for investment
• Timing is critical to exploit current production facilities
CCS Technical Overview - CCLP June 16 2008