Session A13 Chemical Engineering Topics 2
2337
ENHANCED OIL RECOVERY: MAXIMIZING OUR PETROLEUM
RESOURCES
Jacob Chrastina (jcc96@pitt.edu), Brett Lacey (bcl24@pitt.edu)
Abstract—The United States depends on petroleum-based
fuels for a variety of applications and products. In order to
meet the demand for such products more efficient methods of
extracting petrochemicals have been devised, such as
injecting steam and chemicals into reservoirs that have been
previously tapped. Methods of oil recovery are also being
improved by introducing inexpensive polymers that improve
the ability to manipulate injected fluids. Enhanced Oil
Recovery (EOR) is a tertiary method of recovering
additional oil from abandoned reservoirs that yields 30-60%
of the original, previously unavailable oil. [1].
This paper will describe, analyze, and evaluate primary,
secondary, and tertiary oil recovery methods, such as
thermal recovery, chemical injection and CO2 injection. The
main focus will be on CO2 injection and its benefits. Key
factors that affect CO2 behavior will be identified and the
engineering technologies of oil extraction using CO 2 will be
described. The economic value of returning to the nation’s
“stranded” oil resources and the direction and value of
current research and development of different methods of
CO2 capturing and injection will be assessed. This paper will
emphasize the advantages of the CO2 “gelling” method as
well as how this process is completed. The environmental
and societal effects of drilling for petroleum will also be
evaluated in light of the positive effects of CO2 sequestration
and its subsequent injection into reservoirs.
technologies and processes like enhanced oil recovery
(EOR) that yield vastly greater amounts of oil than
traditional methods of oil recovery.
FIGURE 1
U.S. ENERGY CONSUMPTION BY SOURCE [IER]
WHAT IS OIL RECOVERY?
It is clear that basic oil recovery techniques will have trouble
sustaining the future global demand for oil. Engineers and
researchers have therefore designed new ways of extracting
oil that yield a higher percentage of a reservoir’s original oil
than previously possible. Primary and secondary recovery
methods are the most prevalent methods due to their low
cost and simplicity.
There are three main types of oil recovery: primary,
secondary, and tertiary (or enhanced). Primary oil recovery
relies on the rise of hydrocarbons up wellbores, either
naturally or with assistance from artificial lift devices, such
as pumps [3]. Recovering approximately 10% of the
reservoirs’ original oil, this method yields the lowest amount
of oil, but is the most economical. Unlike with more
advanced methods of oil recovery, primary recovery has no
additional expenses for developing additive polymers or
transporting reservoir-injectable gases. However, more
advanced methods naturally, like secondary, yield more oil.
Secondary oil recovery involves injecting water or gas to
increase the well pressure to drive oil to the surface [3]. Both
primary and secondary methods can improve oil extraction
by up to 30% and are inexpensive. However, much of the
easily produced oil has already been recovered from oil
fields in the United States. As a result, even more efficient
Key Words—carbon sequestration, chemical injection, CO2
gelling, energy, enhanced oil recovery, petroleum
engineering, thermal recovery.
PETROLEUM AS A NONRENEWABLE RESOURCE
The industrialized world still depends on fossil fuels and
petrochemicals to operate vehicles and power plants and
manufacture petroleum based materials, such as plastics.
Renewable energy sources alone will most likely not meet
the energy and manufacturing demands of our society for
some time. Currently 37.3% of the United States’ energy
consumption comes from petroleum, while 24.7% comes
from natural gas. Renewable energy, including nuclear,
makes up a mere 17.1% of the United States’ energy
consumption as seen in Figure 1[2].
It is thus important that companies efficiently extract crude
oil and natural gas in order to extend the life of current wells
and produce more domestic petroleum products. Burning
fossil fuels may release greenhouse gases into earth’s
atmosphere, but the world simply cannot switch to
renewable energy sources over night. It will take many years
for “green” energy infrastructure to replace the massive role
of petrochemicals. This is why it is necessary to support new
University of Pittsburgh
Swanson School of Engineering
February 10, 2012
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Jacob Chrastina
Brett Lacey
tertiary or “enhanced” methods of oil recovery have been
developed in order to extend the life of domestic oil
reservoirs [1]. All of these methods are important to
recovering as much oil as possible.
ability to be used on new and mature oil reservoirs. SWIT
injects “treated seawater directly into the reservoir by a
subsea injection pump” [6]. Injecting the seawater directly
into the reservoir can help pinpoint the locations where the
seawater is required for optimal production. SWIT also
allows engineers more flexibility to inject as much treated
seawater as desired into areas where it will benefit the
reservoir the most [6]. The SWIT system can also reduce
environmental impact of oil drilling by decreasing chemical
and power usage [6]. Although a viable method for oil
recovery, water injection methods are not the only means of
extracting more oil.
An alternate method to water injection is gas injection.
This secondary oil recovery method increases the pressure
inside of a reservoir in order to force the remaining oil out of
the oil formation. According to rigzone.com (an
informational website on the oil and gas industry) “gas
injection is a pressure maintenance program that can be
employed on a reservoir at the start of the production
process or introduced after oil production has already started
to lessen” [7]. A technique often used in gas injection is
“cycling…which entails re-injection of produced natural
gas” [7]. In an oil reservoir, as the oil is extracted using
natural gases, the reduced temperature separates the
“condensate from the dry gas in the reservoir” [7].
Condensate, or natural-gas condensate, is a liquid
hydrocarbon mixture that condenses out of natural gasses at
low temperatures. “Condensate liquids block the pores
within the reservoir, making [oil] extraction practically
impossible” [7]. Cycling is a method that can maintain a
more constant pressure, preventing the condensate from
separating and allowing for a continual supply of dry gas to
be injected into the reservoir [7]. Additionally, after an oil
reservoir has been used, the natural gases can be re-injected
into the reservoir. This is an effective disposal technique of
the gas as well as a technique to maintain a stable pressure in
the reservoir [7].
Water and gas injection techniques are both inexpensive
processes that can extend the life and production of oil
reservoirs. Their benefits far outweigh the time and energy
used to effectively carry out their procedures. However,
alternate methods can yield an even higher percentage of oil
recovered.
Primary and Secondary Oil Recovery Methods
In primary oil recovery, oil is forced up the wellbore (the
hole drilled into the reservoir through which oil is extracted)
by the natural pressure generated by gases within the oil [4].
Pumps can also assist the extraction of oil. The biggest
downside to this technique is that only about 10% of the
reservoir’s total oil can be extracted [1]. This percentage is
too low to make drilling efficient and cannot meet global oil
demand. More efficient methods of extraction, known as
secondary recovery methods have been developed to solve
this problem. According to the U.S. Department of Energy,
“secondary recovery techniques…inject water or gas to
displace oil and drive it to a production wellbore, resulting in
the recovery of 20 to 40 percent of the original oil in place”
[1]. This method increases the amount oil produced while
adding minimal costs.
Water injection can be implemented in both on and
offshore drilling facilities, making it a valuable secondary
recovery technique. The injected water increases the
pressure within the well to help move the oil into place [5].
The water flow “sweeps remaining oil through the reservoir
to production wells,” recovering oil that would otherwise be
unreachable [5]. The water used may need to be treated
beforehand, as impurities can clog the “well pores” and even
cause corrosion within the reservoir [5]. The compound most
removed from the water is excess oxygen, which is the main
cause of corrosion during the water flooding process.
In order to inject water into the reservoir, many water
wells must be drilled. Well drilling can involve various
injection positioning techniques: the five-spot pattern, the
seven-spot pattern and line patterns. The five-spot pattern
involves “drilling four water-injection wells in a square
around a production well” while the seven-spot pattern
involves “six water-injection wells surrounding a production
well” [5]. Wells can be drilled in line patterns along the
edges of production wells, forcing oil to their center where
the oil can be extracted. In some reservoirs that contain
heavy oil-a characterization of oil with a high viscosityheated water is injected into the reservoir. The heated water
increases the fluidity of the oil allowing for easier oil
extraction.
Subsea water injection and treatment (SWIT) is a new
recovery method developed by Well Processing, a
Norwegian company whose goal is to provide engineering
solutions for subsea processing. SWIT is a means of
enhancing oil recovery by utilizing seawater to maintain
well pressure and drive oil to wellbores [6]. The downsides
to traditional seawater treatments include expensive and
intensive operating treatment plants. The benefits of this new
method include is that it is more cost efficient as well as its
Tertiary Oil Recovery Methods
Tertiary or enhanced oil recovery (EOR) methods are used
when primary and secondary oil recovery methods have
been exhausted or when they prove to be incapable of
extracting sufficient oil. Heavy oil, poor permeability and
irregular fault lines are all problems that enhanced oil
recovery can resolve by changing the properties of the
hydrocarbons, making their extraction much easier [3].
While primary and secondary oil recovery methods rely
solely on physical manipulation of hydrocarbons, enhanced
oil recovery methods change their chemical “makeup” [3].
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injected water, leading to a “more efficient displacement of
moderately viscous oils” [4]. Adding cleansers known as
surfactants frees trapped residual oil by reducing “oil-water
interfacial tension to almost zero” [3], [4]. Interfacial tension
is similar to surface tension in that cohesive forces are
involved but the main forces involved are adhesive forces
between the liquid phase of one substance with the phase of
another substance. Surfactants decrease these forces [4].
Adding alkaline or basic solutions to polymer-surfactant
methods can convert some acids within the oil to surfactants
that aid in the recovery process and decrease the retention of
the expensive surfactants in the rock [4]. While only
implemented in 1% of all EOR projects, chemical injection
recovery still holds considerable potential to recover oil and
is important in diversifying the methods and processes used
in oil recovery projects [1]. However the method that is
gaining the most popularity is carbon dioxide enhanced oil
recovery due to its effectiveness and the ability to utilize
industrially produced CO2.
Fluids, usually consisting of gases (typically carbon dioxide)
that are miscible with oil, steam, such as air or oxygen,
polymer solutions, and gels are introduced into oil reservoirs
to reduce viscosity and improve flow [4]. This naturally
allows for easier extraction and greater production of oil.
When petroleum engineers decide to use EOR methods on a
well or reservoir, three main types of EOR are typically
considered: thermal recovery, chemical injection, and gas
injection. These processes have been proven to yield 30-60%
or more of the reservoir’s original oil, a much higher yield
than both primary and secondary methods [1].
Thermal Recovery involves heating by introducing steam
into the reservoir to reduce the viscosity of the oil. By
increasing the oil’s ability to flow, it can be more easily
extracted. Currently, thermal recovery accounts for 50% of
applied EOR in the United States and it has historically been
the most widely applied method [3], [4]. There are several
variations of thermal EOR: cyclic steam injection (“huff ‘n
puff”) where steam is first injected, followed by oil
extraction; continuous steam injection, where steam is
continually injected to drive oil to production separate
wellbores; hot water injection; and steam assisted drainage
(SAGD) using horizontal wells, as seen in Figure 2. Steam
assisted drainage “utilizes twin horizontal wells, one drilled
above the other, and steam injection to enhance the recovery
of heavy oil” [8]. Steam is injected into the upper well,
which heats the heavy oil around the well, reducing the oil’s
viscosity [8]. The lowered oil viscosity, coupled with
enhanced oil recovery methods such as carbon dioxide
injection, can increase the percentage of oil recovered. The
biggest advantage to steam assisted drainage is its ability to
allow heavy oil reserves to increase “production efficiencies
[to] 60 percent or better” [8]. Another thermal recovery
method known as “fire-flooding,” involves the injection of
air to oxidize some of the oil. Oxidizing the oil:
 “Produces heat that reduces viscosity for the
remaining oil
 Cracks some high-molecular weight hydrocarbons
into smaller molecules
 Vaporizes some of the lighter hydrocarbons to help
miscibly displace oil
 Creates steam that may steam-distill trapped oil”
[4]. Distillation allows for the separating of crude oil into
more fractions for several different uses, such as transport,
power generation, and heating. The addition of steam allows
this process to occur at much lower temperatures, which
allows hydrocarbons to remain structurally intact that would
otherwise break up at high temperatures. Another method of
enhanced oil recovery involves injecting chemicals into
reservoirs.
Chemical EOR includes polymer flooding, surfactantpolymer flooding, and alkaline-surfactant-polymer (ASP)
flooding [4]. Polymer flooding utilizes long-chained
molecules known as polymers to free trapped oil in
reservoirs. These water-soluble polymers increase the
efficiency of waterflooding by increasing the viscosity of the
FIGURE 2
STEAM ASSISTED GRAVITY DRAINAGE WELLS [8]
MISCIBLE CO2 ENHANCED OIL RECOVERY
In general terms, miscibility is defined as the ability for two
liquids to dissolve in one another. Miscible gas injection
involves the injection of gases, such as nitrogen, natural gas,
or primarily, carbon dioxide to dissolve in oil to make it
easier to extract [3]. Miscible gas injection is the chemical
mixing of gases with oil, rather than the physical
manipulation of the oil by pressure created by injected gas.
Miscible gas injection is a tertiary method that is used in
nearly half of all EOR applications [3]. The most effective
means of oil recovery using gas involves carbon dioxide
dissolving in oil, decreasing its viscosity and increasing its
flow. This facilitates extraction and combats viscous or
“heavy” oil. CO2 is most effective as a supercritical fluid
meaning, “when at or above the critical point of pressure and
temperature…CO2 can maintain the properties of a gas
while having the density of a liquid” [4]. As with injected
chemicals in chemical recovery, the miscible CO2 lowers
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Brett Lacey
interfacial tension between oil and CO2 to virtually zero,
reducing the oil’s viscosity.
Through research and analysis engineers have identified
the factors that influence the effectiveness of CO2 oil
recovery, including sedimentary rhythm, stratum
heterogeneity,
oil
and
CO2
viscosity
ratio,
miscible/immiscible phases, buoyancy/gravity, formation
thickness, diffusion/dispersion, and gas injection rate [9]. All
of these factors are taken into account when determining
whether a reservoir is suitable for CO2 enhanced oil
recovery. One process for evaluating wells is called “rock
core flooding” where a cylindrical rock sample is drilled out,
and then injected with a fluid at high pressures to determine
how well the oil displaces from the rock [4]. Companies can
then discern the best method of oil recovery to employ based
on the collected data from the rock core flooding analysis.
Even though supercritical or dense CO2 helps recover
more oil, it is still often hard to control. The low viscosity of
CO2 causes it to “finger” or diffuse towards production
wells while simultaneously bypassing large amounts of oil
[10]. To combat this, researches have identified three
different ways to control the mobility of dense CO2 [10].
 Reduce CO2 relative permeability in the reservoir
via simultaneous injection with H2O
 Prevent CO2 from escaping from reservoirs by
plugging channels with chemical foams and gels
 Increase the viscosity of CO2 via the addition of a
‘thickening agent’
Initial research on reducing CO2 mobility focused on
decreasing the CO2 saturation within the “porous medium”
(rock formations) by alternating injecting CO2 and water.
The goal was that the CO2 would effectively mix with oil
rather than rock and produce higher oil yields [10]. This
method, however, required longer CO2 injection times and
the injected water would effectively shield CO2-oil
interactions, making it more difficult for effective oil
extraction [10].
Several researchers have investigated the use of CO2foams-aqueous surfactant solutions modified by injected
CO2-to control mobility of CO2. The foams are ideal for
blocking channels that form as a result of the natural
heterogeneity of the reservoir or areas of the reservoir with
high permeability [11], [10]. The foams divert CO2 fluid
flow to areas of lower permeability for greater CO2-oil
interactions, resulting in increased oil recovery [11]. The
foams and gels effectiveness can be greatly improved with
the addition of nanoscale inorganic particles dissolved in its
“fiber network” [11]. This is because the particles “influence
the deformation of the gel and thus enhance the stability and
strength of the gel to different extents” [11]. The more
particles added, the more networks that are formed, and the
stronger the gel. A downside to this method is that the
surfactant required for CO2 foams must readily dissolve in
both CO2 and a non-aqueous (not in water) phase [10]. One
company that is “elevating” the performance of CO2 foam
surfactants is DOW Oil and Gas. Their goal is to reduce the
costs in miscible CO2 enhanced oil recovery by using CO2
foam surfactants to “help improve CO2 conformance” [12].
Their line of products is designed to be especially suitable
for heterogeneous reservoirs or those with mobility control
issues or gravity override [12]. Gravity override is a
condition where CO2 tends to migrate toward the upper part
of the oil production site, also known as the “pay zone” [12].
DOW’s ELEVATE CO2 Conformance Solution can lead to
decreased CO2 utilization rates, and, ultimately, “help move
more oil up the pipe” by using “foams” of supercritical CO2
fluid and water in reservoirs [12].
Most surfactants used in CO2 foams, like those that Dow
Oil and Gas have developed, have both hydrophilic
(attracted to water) and hydrophobic (repelled by water)
segments. The surfactant required would have to instead
have two hydrophobic segments, a CO2-philic segment and
an oil-philic segment [10]. Considering the lack of such
surfactants, another method is more viable for controlling
CO2 mobility, known as CO2 gelling.
By adding a thickening agent or polymer, the viscosity of
CO2 can be increased and thus more easily managed in
underground reservoirs. Additional water injection, as used
with CO2 foams, becomes unnecessary with CO2 gelling.
Increasing the concentration of thickeners has the same
effect [10]. Using thickening agents would also increase
CO2-in-oil saturation, resulting in “a higher displacement
efficiency of the oil, and the corrosive problems associated
with the carbonic acid formation in water-carbon dioxide
mixture would be reduced” [10]. In order to thicken CO2,
inexpensive and effective polymer must be used.
CO2 Gelling Agents
One approach to increase CO2 viscosity is by the addition of
a dilute concentration of a polymer derived from usually two
or more monomeric species known as a copolymer or
heteropolymer [13]. The characteristics of an ideal
copolymer include:
 CO2-philic functional groups to allow the polymer
to dissolve in dense CO2
 CO2-phobic functional groups to increase viscosity
by increasing the force between molecules
(intermolecular forces)
Ideally the copolymer should be able to increase the
viscosity of liquid CO2 by a factor of 2-10 in small
concentrations in order to be considered commercially viable
[13]. Some examples of CO2 thickening polymers:
 Fluoroacrylate-styrene (fluorous)
 Poly vinyl acetate (non-fluorous)
Fluorous copolymers like fluoroacrylate-styrene are the most
effective CO2 thickeners [13]. The fluoroacrylate is highly
CO2-philic, increasing the copolymer solubility. The styrene
is CO2-phobic and thus increases intermolecular forces to
increase viscosity. However, fluorous copolymers are not
feasible candidates for CO2 thickening in oil recovery due to
their high cost and “environmental persistence” [13].
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Brett Lacey
Fluoride can be lethal to aquatic life in high concentrations
by inhibiting enzyme activity, which in turn interrupts
metabolic processes such as protein synthesis [14]. As of
2003, the most effective non-fluorous homopolymer was
poly vinyl acetate (PVAc). University of Pittsburgh
professors Eric Beckman and Robert Enick researched this
homopolymer’s benefits and effectiveness.
Beckman and Enick’s gelling technique utilized the
inexpensive, non-fluorinated homopolymer PVAc to thicken
CO2 to:
 Enhance oil recovery from aging oil fields
 More easily control the flow of CO2 and increase
well stimulation
 Reduce the environmental impact of well
stimulation procedures
[15]. PVAc requires relatively low pressure to attain
dissolution of about 5 wt% concentration at 298 Kelvin (K).
PVAc also has a wide concentration range (1-15 wt%) and
molecular weight range (11-6800 repeated units of the
polymer) at 298 K and between pressures of 13.6 and 67.6
MPa for which it is soluble in CO2. The CO2-philic nature
of this polymer can be attributed to the ability for the acetate
group to dissolve in the CO2 solvent [16]. Similar polymers
were deemed unsuitable as CO2 thickeners due to the fact
that they were less soluble or even insoluble in CO2. Even
though the polymers contained the carbonyl functional
groups that facilitated dissolution, they lacked vital polymer
properties such as crystallinity and less accessible carbonyl
groups [16]. Unfortunately, PVAc is not CO2-philic enough
to be used in the design of CO2 thickeners due to the fact
that other hydrocarbon homopolymers, such as
perfluoroalkoxy (PFA) and polydimethylsiloxane (PDMS),
are markedly more CO2-soluble at lower pressures [16]. It is
thus important that even more CO2-soluble, non-fluorous
polymers are developed to match the solubility of the
fluoroacrylate-base polymers. CO2-phobic groups would
then be incorporated to greatly increase the CO2 solution
viscosity [13]. Current research of non-fluorous polymers
that increase the viscosity of CO2 for easier CO2 mobility
control has made great advances and continues to be an
important aspect of the CO2-based enhanced oil recovery
process. The availability of CO2 and its sources are also
important factors to consider during enhanced oil recovery
processes involving CO2. This problem can be considered in
light of CO2 sequestration.
would otherwise not naturally occur [1]. This, in turn, allows
for more widespread applications of CO2 EOR and higher
oil yields. One such example of industrial CO2 utilization
can be seen with the Dakota Gasification Company’s plant
in North Dakota, which produces CO2 and transports it via a
204-mile pipeline to the Weyburn oil field in Saskatchewan,
Canada. At the field, CO2 is helping to add an additional 25
years of life to well and produce approximately an additional
130 million barrels of oil that would have otherwise been
abandoned [1].
CO2 can also be sequestered from the atmosphere.
However, the carbon dioxide created from carbon
sequestration must be efficiently transported to the drilling
site, which can pose difficulties. Some reservoirs have easy
access to carbon dioxide springs that can provide
inexpensive as well as speedy access to the CO2 required for
enhanced oil recovery. Other sources require miles of
pipeline and excessive amounts of resources to simply gain
access to a source of carbon dioxide large enough to begin
CO2 enhanced oil recovery. However, there is another
source from which carbon dioxide can be captured. The
combustion of hydrocarbons in oil refineries is a leading
source for carbon dioxide gas [17]. Oil refineries have little
drive to capture the carbon dioxide they pump into the
atmosphere, but a drive can be instilled in producers of CO2.
“Sequestration of CO2 currently yields no economic
benefits in jurisdictions without carbon emissions
restrictions, future regulations of CO2 emissions in the
context of climate-change policies may generate such
benefits if EOR projects are allowed to earn credits for units
of CO2 sequestered” [18].
Producers who supply
sequestrated carbon dioxide will thus be able to earn
revenues from the increase in oil production as well as from
the government, who will provide the credit for
sequestrating the CO2 [18]. Giving companies that produce
high yields of CO2 emissions incentive to sequestrate CO2
will provide benefits for the environment by reducing the
amount of CO2 pumped into the atmosphere, and encourage
more efficient oil production.
ECONOMIC, ENVIRONMENTAL, AND SOCIETAL
IMPACTS OF EOR
Miscible CO2 EOR is a highly beneficial method
environmentally, economically, and societally. The
environmental benefits of enhanced oil recovery using
carbon dioxide do not stop at the possibility of sequestrating
the CO2 from the atmosphere. CO2 is environmentally
benign, nonflammable, inexpensive, non-toxic, and available
from natural reservoirs in large quantity [13]. These
characteristics make CO2 an alluring compound to use for
EOR. A nonflammable gas is ideal for the extraction of oil,
as a flammable one could potentially create an explosion in
the reservoir. The ability to dispose of the carbon dioxide in
the reservoir after oil production has ceased is another factor
that makes CO2 injection a valuable method for extracting
CO2 Sequestration
CO2 flooding of reservoirs not only increases oil recovery,
but also “reduces the amount of CO2 released in the
atmosphere by permanently storing it in the formations” [9].
Until recently, most of the CO2 used in oil recovery projects
has been extracted from naturally occurring springs of CO2
[1]. Now many industrial plants including natural gas
processing, ethanol, fertilizer, and hydrogen plants, can
produce CO2 to be used in oil recovery in places where CO2
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Brett Lacey
oil. The availability of carbon dioxide gas in nature makes it
an easy compound to use in enhanced oil recovery. The
ability to take carbon dioxide out of the atmosphere and
ultimately leave it in the reservoir after oil recovery is a
major environmental benefit that does not result from
primary and secondary recovery methods. The impact of
developing enhanced oil recovery methods does not stop at
the environmental level.
The United States currently holds a domestic oil reserve of
approximately 21.9 billion barrels. “The U.S. Department of
Energy estimates that there currently 89 billion barrels of
additional oil trapped in onshore reservoirs” that could be
recovered by implementing enhanced oil recovery (EOR)
methods, such as carbon dioxide injection [3]. If this
untapped oil were added to the nation’s reserves, the country
would “rank fifth in the world for the size of its reserves”
[3]. Increasing the size of the nation’s oil reserves would
ultimately reduce foreign oil dependence, and reduce the
amount of capital America gives to foreign governments.
Foreign policy issues like these are important to American
citizens, and their support for such ideas will in turn garner
support for the growth of EOR methods. Another major
societal benefit of CO2 sequestration is outlined in Science
Direct’s article on co-optimization of enhanced oil recovery
and carbon sequestration. The article states that “profits from
CO2-enhanced oil output can be used to ‘jump-start’ the
building of pipelines and other infrastructure required for
ultimately much larger-scale sequestration in non-oil-bearing
formations” [17]. This can potentially maximize the amount
of oil recovered from reservoirs, providing more oil for
consumption.
Although it is clear that EOR methods can more efficiently
produce oil, these processes do not come without costs. The
price of oil and other petrochemicals must justify the
investment in oil recovery methods such as CO2 injection.
“Each reservoir requires a tailor-made approach to enhanced
oil recovery,” says Gerald Schotman, Shell’s Chief
Technology Officer [19]. This is why petroleum and
chemical engineers must research a particular well in order
to find the optimal method for recovery. With advancements
in EOR technology, oil recovery yields are dramatically
improved. According to Gerald Schotman, Shell’s Chief
Technology Officer, “making recovery just 1% more
efficient would release 88 billion more barrels of oil equivalent to three years’ annual production at today’s
levels” [19]. If all oil reservoirs were to increase their oil
capacities by 10-20%, the United States economy would
indeed benefit. An increase of this magnitude could extend
the life of the world’s oil supplies by 10-20 years [19].
These statistics support and outline the goals of future EOR
research. With an increase in the life of oil, other renewable
sources of energy will have more time to be developed and
integrated into national infastructure.
ENGINEERING EFFICIENCY
All of these methods of oil recovery are important to society
and engineering because they utilize engineering research to
maximize domestic petroleum energy resources at a time
when domestic oil production is low relative to foreign oil
imports. Economic stressors along with more stringent
environmental standards should also allow EOR to flourish
as an efficient and cost-effective method of extracting oil.
Primary, secondary, and tertiary methods of oil recovery all
help to extract oil in different ways to yield the highest
percentage oil possible. As each reservoir is different, each
needs to be assessed individually to determine the most
effective method of oil recovery that should be implemented.
Even reservoirs that have been previously tapped can be
reevaluated for enhanced oil recovery and at minimal cost
due to that fact that a large amount of infrastructure is
already in place. It has been determined that the most
efficient method of enhanced oil recovery is miscible CO2
recovery that utilizes thickening polymers to allow greater
CO2 mobility control. The research contributed by
University of Pittsburgh professors Eric Beckman and
Robert Enick has helped identify and test non-fluorous
polymers as CO2 thickening candidates, such as poly vinyl
acetate. As the government develops incentives to
sequestrate CO2, U.S. cities become cleaner, and more oil
gets recovered. All the processes and materials that go into
enhanced oil recovery allow for greater oil yields (up to 4060% more of the original oil) while in the meantime,
scientists and researchers develop new technologies to
develop renewable energy sources to support our future
energy needs.
REFERENCES
[1] (2011, December 12). “Enhanced Oil Recovery/CO2 Injection.” U.S.
Department
of
Energy.
[Online].
Available:
http://fossil.energy.gov/programs/oilgas/eor/
[2] (2009). “Energy Overview.” Institute for Energy Research. [Online].
Available: http://www.instituteforenergyresearch.org/energy-overview/
[3] (2012). “What Is EOR, and How Does It Work?” Rigzone. [Online].
Available:
http://www.rigzone.com/training/insight.asp?insight_id=313&c_id=4
[4] (2007, November 27). “Enhanced Oil Recovery (EOR).” Teledyne Isco.
[Online].
Available:
http://www.isco.com/WebProductFiles/Applications/105/Application_Note
s/Enhanced_Oil_Recovery.pdf
[5] (2012). “How Does Water Injection Work?” Rigzone. [Online].
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Jacob Chrastina
Brett Lacey
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ACKNOWLEDGMENTS
We would like to thank Pitt professors Eric Beckman and
Robert Enick whose research on non-fluorinated compounds
to gel CO2 inspired us to write our conference paper on the
topic of enhanced oil recovery using carbon dioxide
injection. We would also like to thank the writing center and
our chair, Megan Boerio and co-chair, Pete Hoffman.
ADDITIONAL RESOURCES
S. Hove, M. Menestrel, H. Bettignies. (2002, January 23). “The oil industry
and climate change: strategies and ethical dilemmas.” [Online]. Available:
http://www.econ.upf.edu/~lemenestrel/IMG/pdf/climatepolicy.pdf
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