Download - LW BEER 1.6.10
An introduction to the geology behind Carbon Capture & Storage and Enhanced Geothermal
Logan WestBeijing Energy Network6 Jan. 2010
Three types of rocks◦ 1. Sedimentary – sandstone, limestone, shale
◦ 2. Igneous – granite, basalt
◦ 3. Metamorphic – marble, quartzite
The Earth’s Layers Plate Tectonics
Source: IPCC, 2005
What do with the CO2?◦ Not up
◦ Not in the oceans
◦ How about the subsurface
So what does the subsurface look like?
?
Idealized SubsurfaceRealistically, sometimes complicated
For the purposes of CCS, we are interested sedimentary basins, depressions in the earth’s crust into which sediments accumulate. They often have a bowl shape.
Three main zones for CO2 injection:◦ Oil and Gas Reservoirs
◦ Deep Saline Aquifers
◦ Coal Beds
CO2 is injected in a supercritical state (31.1°C degrees C, >7.39MPa) so it behaves like a gas but with a density of a liquid◦ Doesn’t float away as quickly or easily
Subsurface accumulations of oil and gas that are contained in porous rock layers and trapped by an impermeable formation above (caprock)
Common Reservoir Rock: sandstone, limestone, and dolomite
Common Caprock: shale, evaporite, or mudstone
With respect to CCS, they can be used for Enhanced Oil Recovery (EOR) and Enhanced Gas Recovery
Source: IPCC, 2005
An aquifer is a body of permeable rock in which considerable amounts of water can be stored and through which groundwater flows
Geologically, it is essentially the same as an oil or gas reservoir. The greatest difference is that the fluid contained in aquifers is majority water rather than hydrocarbons.
Shallow aquifers are often used for drinking, the depth and high salinity of these aquifers make them undesirable for drinking, agriculture or industry
Source: CO2 capture project
More unknown option
Due to the nature of the coal, CO2 will typically adsorb onto external pockets along coal deposits and overtime is absorbed into the coal
A driving factor for Coal bed storage is the opportunity for Enhanced Coal Bed Methane recovery (ECBM) in which CO2 replaces Methane (CH4) on the
1. Stratigraphic Trapping
◦ A good caprock should be:
Laterally extensive
Will prevent vertical migration (low permeability, high capillary entry pressure, hydrocarbon trapping)
Expectations that present faults and fractures will seal
Adequate Rheological Properties
Info Source: WRI CCS Guidelines, 2008Images Source: http://www.co2captureproject.org/
Stratigraphic Trapping
Structural Trapping◦ Heterogeneities
◦ Not only caprock blocks CO2
Source: http://www.co2captureproject.org/(left);
Stratigraphic Trapping
Structural Trapping
Residual Trapping ◦ Stuck in the pore space
Source: http://www.co2captureproject.org/
Stratigraphic Trapping
Structural Trapping
Residual Trapping
Solubility Trapping◦ CO2 dissolves into water
◦ No longer buoyant
Hydraulic Trapping
Source: http://www.co2captureproject.org
CO2 (g) + H20 H2CO3 HCO3- + H+
CO32- + 2H+
Stratigraphic Trapping
Structural Trapping
Residual Trapping
Solubility Trapping
Mineralization◦ Bicarbonate (HCO3) formation
◦ Once it’s in mineral (i.e. solid) form, it’s stuck for millions of years
3 8 2 2 2 3 10 2 323 KAlSi O 2H O 2CO KAl OH AlSi O 6SiO 2K 2HCO
+ -
3 8 2 2 2 3 10 2 323 NaAlSi O +2H O+2CO NaAl OH AlSi O +6SiO + 2Na + 2HCO
2 2 8 2 2 4 3 10 3 24 23 CaAl Si O +4H O+4CO CaAl OH AlSi O + 2Ca(HCO )
Storage Mechanisms Storage Risks
Source: WRI, 2008
Key Parameters:◦ Capacity Can it hold all the CO2?
Factors: size of reservoir, volume of pore space, CO2 density
◦ Containment Will it stay there?
Factors: Caprock Integrity, effect of other storage mechanisms
◦ Injectivity Can we pump it in as fast as it’s piped to the site?
Factors:Permeability
Basin Depth between 800–3000m – for supercritical state ◦ Behaves like a gas but dense like a fluid (keeps it from “floating” away
quickly)
Image Source: The World Bank, The cost of pollution in China, 2007
Economics
Conflict of interest (minerals, petroleum, water)
Protected areas
Population
Etc.
Thorough Site Selection and Characterization
Monitoring plan◦ Start prior to injection
◦ Continue decades after injection
Reservoir Models◦ Create as you learn about the geology
◦ Update with monitoring data
◦ Use to predict how CO2 will move overtime
Risk Analysis◦ Identify known storage risks
◦ Create plans for how to protect against them
◦ Be prepared with plans if leakage does occur
Source: IPCC, 2005
Seismic Monitoring
Similar anthropogenic projects or natural formations◦ Acid gas (H2S) underground injection
◦ Liquid waste underground injection
◦ Natural CO2 reservoir
Thus far proven in CO2 Storage demonstrations
IPCC Quote:
In Salah, Algeria
Weyburn, Canada
Sleipner, Norway
“Observations from engineered and natural analoguesas well as models suggest that the fraction retainedin appropriately selected and managed geologicalreservoirs is very likely25 to exceed 99% over 100 yearsand is likely20 to exceed 99% over 1,000 years.”
Source: IPCC, 2005
CO2 in heavy concentrations (>7-10% air composition can lead to human death)◦ Is denser than air so can accumulate in low lying areas until
is dispersed by wind
Forms carbonic acid in water ◦ Render water non-potable, bad for agriculture◦ Can leach heavy metals
Can lead to acidification of soil◦ Bad for organisms◦ Can leach heavy metals – worse for organisms
There are means of remediation to plug leaks and minimize impacts
Source: IPCC, 2005
Storage ProspectivityEmissions for Storage Regions
Source: APEC 2005
NRDC:
PNNL: China may have 2,300 Gt (>100yr demand) of onshore CO2 storage capacity:
• 2,290 Gt in deep saline formations• 12 Gt in coal seams • 4.6 Gt in oil fields • 4.3 Gt in gas fields
Source: http://www.nrdc.org/international/chinaccs/default.asp
Source: PNNL, Establishing China’s Potential for Large Scale, Cost Effective Deployment of Carbon Dioxide Capture and Storage, October 2009, PNNL-SA-68786
Storage in China faces several challenges◦ Geological Complexity
◦ Local Capacity Issues for EOR
◦ Unmarked, poor quality wells – potential leakage sources
◦ Data Accessibility – overall lack of data, data that exists often proprietary to oil, gas, and mining companies
Data
Availability
Capacity
Envelope -
Volume and
Reservoir
Quality
Geological
ComplexityContainment Injectivity Well Integrity
Reservoir
Availability
Pipeline
Distance
Conflicts of
Interest
Dagang Oilfield Province
Shengli Oilfield Province
Huimin Sag Saline Formations
Kailuan Mining Area
Low risk
Medium risk
High risk
Source: Espie, T. COACH WP4: Recommendations and Guidelines for ImplementationCOACH-NZEC Conference, 28 Oct. 2009
Image showing relative risk in possible storage fields in China’s Bohai Basin
Storage capacity◦ oil fields: from 10 to
500MtCO2
◦ Deep saline aquifers: ~ 20GtCO2
◦ Coal mines: 500GtCO2 BUT availability and injectivity questionned due to extremely low permeability
Source: Kalaydjian, F. Key findings from NZEC Phase I: COACH OverviewPresented at NZEC-COACH Conference, Oct. 28, 2009
• Further analysis doesn’t necessarily support theoretical estimates
Continue In-depth investigation to achieve more realistic capacity estimates and identify exact storage sites
Improve access to data
Begin storage demonstration projects
Continue to improve reservoir modeling and characterization technology
Define tools and best-practice for site characterization and monitoring
ENHANCED GEOTHERMAL
SYSTEMS (EGS)
WHAT DOES GEOTHERMAL MEAN?
The Earth’s core is ~5,500C.
Convection, Conduction, and Radiation transport
heat to the crust
Geothermal Gradient
Average surface temperature is 15C
Temperature increases with depth at a rate ranging
from 15 C/km to 50 C/km
HOW DO WE USE GEOTHERMAL ENERGY?
Direct Use: Heat Pumps, Bathing, Space
Heating, etc
2000 75,000+ GWh worldwide usage
Electric Power Generation: via steam powered
turbines
2003 56,000+ GWh worldwide usage
Source:Glitner US Geothermal Energy Market Report 2007
WHAT ARE ENHANCED GEOTHERMAL
SYSTEMS (EGS)?
Hydrothermal Energy: natural hot springs
Shallow: < 3km depth
In situ, High Temp Water: > 150C
Limited Resources
Enhanced Geothermal
Deep: 3 – 10km depth
Hot Rocks: Temperatures ranging 150 to 400+C
No Natural Reservoir: Reservoir must be created and
water pumped in
Vast Resources
BEST EGS REGIONS
Looking for High Heat Flow and/or High
Temperature Gradients
Plate Boundaries – Geologically Active
Sedimentary Basins
USA GEOTHERMAL RESOURCES
Source: MIT Future of Geothermal Energy, 2006
Simplified cartoon rendering of EGS plant (left) and schematic of Geothermal Binary Power Plant (right): http://www.geothermal-energy.org/geo/geoenergy.php
KEYS FOR SUCCESS
Most important factor is Flow Rate
Combination of permeability, volume of fractured
rock, surface area of fractured rock
Need to have as little loss of water as possible
POTENTIAL FOR EGS
USA Recoverable Resource1:
In the USA alone, 28.95 million Terrawatt hours
Could power the world for 590 years at 2007
consumption levels
Other countries beginning to do analyses
Predicted USA Development of EGS through the
year 2050 (MWe)2:
2015 2025 2050
1,000 10,000 130,000
1: Values from MIT Future of Geothermal Energy (2006) and BP Statistical Review of World Energy 2007 2: NREL Geothermal Resources Estimates for the US 2006
ADVANTAGES OF EGS
Renewable
Energy Security
Limits demand for fossil fuels
Every Nation possesses some geothermal resource
Baseload Power Source
Constant, non-fluctuating energy
Hydrothermal Plants operate at 95% capacity
Economically competitive
Cost currently estimated 8-14 cents/hr
Tremendous incentive for natural technology growth
Minimal Environmental Impact
ENVIRONMENTAL BENEFITS OF EGS
Near Zero Emissions*
Limited Plant Surface Area*
7x less than Nuclear; 35x less than Coal
Induced Seismicity comparable to oil, gas, and
mining operations
Environmental
Emissions for U.S.
Power Plants
Carbon Dioxide
(CO2)
(Lbs/MWh)
Sulfur Dioxide (SO2)
(Lbs/MWh)
Nitrogen Oxide
(NOx)
(Lbs/MWh)
New Coal Plant** 2068 3.6 2.96
Old Coal Plant 2191 10.39 4.31
New Natural Gas Plant 850 0.018 0.31
Geothermal Flash
Plant60 .35*** 0
Geothermal Binary
Plant0 0 0
* Data from NREL Geothermal Report
** New = Coal Plants built in 1990s; natural gas combined cycle plants built in 2002
*** This is indirectly
POTENTIAL PROBLEMS
Induced Seismicity
Hydrofracturing rocks by nature sets of micro-
earthquakes
Recorded magnitude 3.2 earthquake in Basel,
Switzerland argued to be caused by local EGS plant
There are over 130,000 Magnitude 3-3.9 earthquakes
in the world each year with minimal damage at most1
A magnitude 4.9 (almost 100x greater than Basel)
occurred in Yunnan New Year’s Day 2010. It received
no press.
Technological Difficulties
1: USGS
WHAT STAGE IS EGS DEVELOPMENT AT?
Successes1:
Pilot projects can create reservoirs, generate power on the
scale of a few megawatts
Power plants already capable of converting supercritical
water (temp of 400 C) into electricity
Technological Obstacles:
Better control of reservoir creation
Drilling equipment withstand > 5km depth and 200C
environment
Maintaining a commercially viable, production flow rate
Economic Obstacles2:
Capital Intensive (drilling and plant construction)
Overcoming initial “Valley of Death” investment (est.
US$3.5 million per MW)
1: Source – MIT Future of Geothermal Energy 2006 2: Glitner US Geothermal Energy Market Report 2007
GEOTHERMAL RESOURCES OF CHINA:
HEAT FLOW
Source: Hu et. al., 2001
GEOTHERMAL REGIONS OF CHINA
High Grade Medium to Low Grade
Source: Pang, 2009 http://english.iggcas.ac.cn/pangzhonghe/index.html
CHINA, GEOTHERMAL, & EGS
China is the world leader in total Direct Use geothermal energy1
China only utilizes 5% of hydrothermal resources it deems economically exploitable2
Southwest China (Tibet, Sichuan, and Yunnan) and the Southeast Pacific coast possess large high-grade geothermal resources2
Sedimentary Basins (also a key source) cover 36% of China3
Currently China has only one hydrothermal power plant in operation at Yangbajain (28 MW) providing ½ of Lhasa’s electricity2
If China were to possess only 1/10th of the recoverable resources of the USA, it could still meet its 2008 primary energy demand for 333 years4
1: Glitnir US Geothermal Energy Market Report 2007; 2: Ministry of Land and Resources; 3: Pang, Z. 2009; 4: Calculations from Data of MIT & BP Reports
POTENTIAL NEXT STEPS FOR CHINA
Conduct full Geothermal resource assessment
Already has plans for new hydrothermal resource
assessment
Promote investment of deep drilling technology
investment and other Geothermal Technologies
Further develop its hydrothermal resources
Plan for EGS pilot plants based on finding of
geothermal resource assessment
ACKNOWLEDGMENTS
Tsinghua-BP Center
World Resources Institute
National Resources Defense Council
Princeton In Asia
Zhang Dongjie