An INTRODUCTION TO ISSUES IN ENVIRONMENTAL
GEOLOGY OF OIL SHALE AND TAR Sands
Jeremy Boak, Colorado School of Mines
Justin Birdwell, U. S. Geological Survey
Outline
‣ Oil shale and tar sand overview
‣ Environmental issues
‣ 30th Oil Shale Symposium highlights
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What is oil shale?
‣ Organic rich sedimentary rock
‣ Formed in lake or marine environments
– Commonly carbonate rich; many not be
classical shale (fissile argillaceous mudstone)
– Contains kerogen – solid hydrocarbon
– Primarily algal and bacterial precursor
– Immature precursor to oil & gas
‣ Produces oil upon heating
‣ Or deeper burial
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What is shale?
Shale Averages*
Vernik & Landis, 1996
Pettijohn, 1975
U. Green River
L. Green River**
Polish Gas Shale
Q+F=Clay
Carbonate=Clastic
Calcite +
Dolomite
calcareous/
dolomitic mudstone
Siliceous Dolomite
Eagle Ford
Niobrara
siliceous
marlstone
argillaceous
marlstone
Monterey
argillaceous
mudstone
(traditional shale)
Montney
Haynesville
L. Marcellus
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Barnett Muskwa
Bakken
Average Shale
Clay Minerals
* Data from Hall 2010
** Burnham et al. 2009
Bazhenov
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siliceous
mudstone
Siliceous shale
Monterey
Porcellanite
Quartz +
Feldspar
Petroleum system perspective
Oil shale
Shale-hosted oil
Shale gas?
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Oil shale resource estimates
11. Canada
13. Sweden
10. Estonia
Ordovician-Devonian, marine
Carboniferous, lacustrine
Mesozoic, marine
Cambrian-Ordovician, marine
Ordovician, marine
15,241 million barrels
6,114 million barrels
16,286 million barrels
4. Russia
270,944 million barrels
Ordovician-Jurassic, marine
1. Green River Formation
>3,000,000 million barrels
15. Ukraine
Tertiary, lacustrine
4,193 million barrels
16. Kazakhstan
2,837 million barrels
3. China
328,000 million barrels
Primarily Tertiary, lacustrine
2. Other United States
12. Thailand
619,000 million barrels
6,401 million barrels
Eastern Devonian, Phosphoria,
Heath
Devonian-Permian, marine
Tertiary, lacustrine
9. Australia
24,000 million barrels
Cretaceous, marine
Tertiary, lacustrine
8. Morocco
37,800 million barrels
Cretaceous, marine
17. Turkey
1,985 million barrels
Tertiary, lacustrine
14. Egypt
5,700 million barrels
Cretaceous, marine
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7. Brazil
80,000 million barrels
Permian, lacustrine or marine
Tertiary, lacustrine
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5. Israel
6. Jordan
Cretaceous, marine
Cretaceous, marine
250,000 million barrels
102,000 million barrels
Data Source: J. R. Dyni, Geology
and Resources of Some World OilShale Deposits, (2006) U. S. Geological Survey Scientific Investigation
Report 2005-5294, U. S. Geological
Survey, Reston VA
Updates from 26th through 30th Oil
Shale Symposia, Colorado School of
Mines
In situ vs. external extraction – oil shale
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In situ vs. external extraction – oil sands
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Environmental issues for oil shale & tar sand
‣ Novel versions and combinations of familiar problems
‣ Consumption of water
‣ Potential contamination of water & atmosphere
‣ Challenges to habitat and range
‣ Interactions of ground water, surface water, soil, rock, air
and ecosystem create a linked system
–
Exciting challenge to the research community to define & execute
–
Challenge to communicate research results & implications effectively
–
In a politically charged environment
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Energy and carbon
‣ Extraction of useable hydrocarbons requires a larger
input of energy than traditional hydrocarbons
–
Separation of heavy oil from poorly consolidated tar sands
–
Pyrolysis of solid kerogen in oil shale
‣ Raises questions of energy return on investment &
carbon footprint
‣ Can alternative energy sources merge with these
unconventional hydrocarbon resources to mitigate
GHG emissions?
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Water use and quality
‣ Water use potentially higher
–
despite advances in conservation & reuse of process water
‣ Mobilization of hydrocarbons underground
–
Target of some production schemes for oil shale and tar sand
–
Carries potential for contamination of ground water
‣ Particulate air emission
–
Surface mining & processing may contaminate surface & ground water
–
A novel contaminant pathway not yet clearly addressed
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Land and ecosystem issues
‣ Large areal extent of both
types of resources
‣ How to manage land to
preserve ecosystems where
these resources exist
‣ Migration corridors of
significant concern
‣ High areal density of oil
shale may mitigate concern
‣ Disposition of spent
materials
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Multiple use issues for oil shale
‣ Current development of
deeper tight gas sands
of Mesa Verde Group
‣ Other possible deeper
targets
‣ Dual resource issues
– Saline minerals of Green
River Formation
‣ Environmental
baseline?
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Oil Shale Symposium environmental themes
‣ Water consumption
‣ Groundwater contamination
‣ Water systems evaluation
‣ Climate change impacts on water supply
‣ CO2 emissions from oil shale production
‣ Reuse of spent shale
‣ Species threats
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