Taxonomy of Unconventional Oils:
Chemical Makeup and Climate Considerations
Deborah Gordon
Senior Associate
Carnegie Energy & Climate Program
February 8, 2012
What Are Unconventional Oils?
• The term “unconventional oil” is synonymous with oil
that cannot be produced, transported, or refined using
traditional techniques
• The transition to unconventional oils might be viewed as
a technologically and economically driven re-definition of
the resource base for liquid hydrocarbon fuels
• The chemical make up of these petroleum resources—
and their climate impacts—can be vastly different from
one another and from conventional oil
Conventional Crude Oil
C1 to C60
Molecular weight ~ 200
 Hydrogen-rich hydrocarbon compounds with
fewer carbon atoms and lower molecular
weights
 Crude continuum from high quality “light,
sweet” crudes (Libya and Nigeria) to “heavy,
sour” crudes (Venezuela)
 Lighter, sweeter crudes have chemical make ups
that yield today’s marketable petroleum
products (gasoline, diesel, jet fuel)
Oil Sands and
Heavy Oil
 Contain large, carbon-laden hydrocarbon compounds
 Extra heavy oils (also called bitumen), are extremely
viscous – sometimes nearly solid
 Typically contain high concentrations of sulfur and
metals such as nickel and vanadium
 Require pre-processing into synthetic crude oil
 Removal by mining or in-situ with different impacts
Oil Shale
 The petroleum component of the oil shale (kerogen) is less
mature, and has not yet been fully transformed into oil or
natural gas
 Kerogen in the oil shale cannot be pumped directly from
the ground or refined with traditional techniques
 Oil shale must be heated to high temperatures to
transform the kerogen into an upgraded hydrocarbon
product, similar to diesel
Tight Oils
 Referred to as Shale Oil
 Produced from low-permeability
siltstones, sandstones, and carbonates
 Extraction methods are
unconventional—fracking and
horizontal drilling
 Oils vary but tend to have similar
properties (density, sulfur content) as
conventional oil product
 Heavier hydrocarbons, more diesel-like
make up
• Unconventional oils are
an evolving species of
new petroleum fuels
• Their quality will change
over time
Source: IEA, David Fyfe,
http://csis.org/files/attachments/110621_Energy_Fyfe.pdf
As oil quality changes so do
the processes to refine them
and the products they yield
Greenhouse Gas Emissions
Comparing Conventional and Unconventional Oils
• Life-cycle greenhouse gas (GHG) emissions from oil sands are
reported to increase by 5 to 15 percent [per mile driven]
compared to the average crude refined in the United States
• Well-to-wheel emissions are one measure to compare the
lifecycle GHGs from motor vehicles using different fuels
• Per barrel produced and per energy produced, GHG emissions
increases from unconventional oils are estimated to be
significantly greater than conventional oil—3x or more
Climate Considerations
of Unconventional Oil Production
Low
Emissions
Estimate
High
Emissions
Estimate
Average
Emissions
g CO2/MJ
g CO2/MJ
g CO2/MJ
Conventional Oil
4.4
4.7
4.6
Oil Sand and Heavy Oils
9.3
16
12.6
3x
Oil Shale
13
50
31.5
7x
Coal-to-Liquids (CTL)
--
--
101
22x
Petroleum Fuel
Estimate
Average
Increase
UO compared to
Conventional Oil
All fuels except CTL: IEA Energy Technology Network, May 2010, http://www.iea-etsap.org/web/E-TechDS/PDF/P02-Uncon%20oil&gas-GS-gct.pdf
CTL: EU Fuels Directive Draft, 2009
Managing Climate Impacts
from Unconventional Oils
 Global unconventional resources are massive and largely untapped
 Unconventional oil in the ground may be far greater than all of the
world’s currently economically recoverable conventional oil
 The paradigm shift to UOs highlights the need for early and
comprehensive assessment of the environmental and social impacts
of resource development, including the need for mitigation strategies
and long range planning
 Climate, environmental, and other social factors are not being fully
considered in early UO developments worldwide.
Greenhouse Gas Emissions
Critical aspects [of unconventional oils] are often
not well understood—for instance, the greenhouse
gas (GHG) emission intensity or effects on water
supplies.
Source: National Petroleum Council, September 15, 2011
New Fuels Require New Rules
• New oils will replace the
loss of more than one-half
of global conventional oil
production through 2035
• Understanding and
managing GHGs from
Unconventional Oils
matters to maintain the 2 oC
climate safety threshold
Source: ExxonMobil, The Outlook for Energy: A View to 2040, 2012