I.A Jimoh, Rudyk S.N and Søgaard E.G
Section of Chemical Engineering,
Department of Chemistry, Biotechnology and Chemical Engineering,
Aalborg University, Campus Esbjerg
Denmark
• Introduction
•Enhanced Oil Recovery Methods and why are they needed?
• Microbial Enhanced Oil Recovery
• Experimental Study (Objectives)
• Results of Laboratory Investigations
• Conclusions/Further Works
2
•
Currently global energy production from
fossil fuels is about 80-90% with oil and
gas representing about 60 %
•
During oil production, primary oil
recovery can account for between 30-40
% oil productions
•
While additional 15-25% can be
recovered by secondary methods such as
water injection leaving behind about 3555 % of oil as residual oil in the
reservoirs
•
This residual oil is usually the target of
many enhanced oil recovery technologies
and it amounts to about 2-4 trillion
barrels (Hall et al., 2003)
www.energyinsights.net
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Enhanced oil recovery (EOR) methods aimed to recover additional oil after primary recovery
or natural drives in the reservoirs
•Water flooding (water injection)
•Gas injection (not miscible)
•Carbon dioxide flooding (miscible)
•Steam injection and in-situ burning
•Surfacants or foams injection
•Microbial Enhanced Oil Recovery Methods
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Use of microbes to improve oil recovery, established by Beckman 1926
How much additional oil can be produced? Up to 60% oil in place after primary
recovery
5
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Bioproduct
Acids
Effect
Modification of reservoir rock
Improvement of porosity and permeability
Biomass
Reaction with calcareous rocks and CO2 production
Selective or non selective plugging
Emulsification through adherence to hydrocarbons
Modification of solid surfaces
Degradation and alteration of oil
Reduction of viscosity and oil pour point
Desulfurization of oil
Gases (CO2, CH4, H2)
Reservoir repressurization
Oil swelling
Viscosity reduction
Increase permeability due to solubilization of carbonate rocks by
CO2
Solvents
Dissolving of oil
Lowering of interfacial tension
Surface-active agents
Emulsification
Polymers
Mobility control
Selective and non-selective plugging
After Janshekar, 1985
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Microbial Enhanced Oil Recovery (MEOR) is a technology using micro-organisms to
facilitate, increase or extend oil production from reservoir.

Average size of microbe is one micron, 10,000th of cm. More
than 27,000 species of bacteria have been identified.

The bacteria, which can be mobile or non-mobile, have three
basic shapes: round (coccus), rod (bacillus) and spiral (spirillum).

Microbes are the most primitive earth's single celled
organisms.

Their basic role in life is to recycle the components of living
organisms, converting them to the nutrient chemicals used by
plants in photosynthesis & chemosynthesis.
Shape of Microbes
During last 15 years some countries began to develop and apply MEOR methods
successfully again such as USA, Russia, Romania, Germany, Malaysia, China,
India, Norway, UK, Venezuela, Iran, Trinidad among others.
More than 300 cases of MEOR methods application – mostly
of single well stimulation – were reported.
1.
2.
3.
Selective Plugging
Hydrocarbon Chain Degrading Bacteria
Cyclic Microbial Recovery
Znamenskiy Field, Russia:
•
Microbes of activated sludge and
bio-stimulators application on the last
stage of carbonate rock field
development.
•
Totally during 1996-2002, 68
injectors were treated.
•
1 t of bio-product gave up to 756 t of
oil.
Microbes plug the washed out tunnel forcing
water to flow through yet unwashed areas.
Stimulating naturally occurring bacteria that feed on
oil to create conditions that release residual oil from
the reservoir.
The interfacial tension between water and oil is
lowered resulting in easier oil recovery.
Statoil
 Applying an aerobic MEOR technique to the
development of Norne field.

Considers that the technique will produce about 32
million incremental barrels; about 6% above what
would otherwise have been recovered.
Carbon hungry bacteria are injected by Statoil
into the Norne field to free oil clinging to the
reservoir rock and enhanced recovery
A large group of bacteria is able to cut hydrocarbon
chains thus decreasing the viscosity of oil.
The microbes degrade hydrocarbons to the
following components
Heavy oil field in
Western Siberia, Russia,
January, 2006
Before Treatment
After Treatment For a
Period 3 Months
Production rate
5 - 7 m3/h
15 -19 m3/h (mostly 1617 m3/h)
Water cut
48 %
25 %
Quality of oil
-
improved
Viscous Oil
(Bokor Field Malaysia)
Before Treatment
After Treatment Over
past 5 months
(post MEOR)
Production rate
152 b/d
334 b/d
Water cut
75 %
45 %
Lazar et al., 2007:Microbial Enhanced Oil Recovery
 Microbes replicate -process is self
sustaining
 Eliminates logistical hassle
Self- directing
 Find their own carbon source in the
reservoir
 Create recovery enhancing chemicals
where needed
 A Rather cheap method compared to
CO2 injection
Selfpropagating
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
High salinity

High temperature

High pressure in oil reservoirs

pH

Pore geometry
The big question is how to find the right candidate!
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1). Can the selected bacterium Cloostridium Tyrobutyricum produce desired
metabolites needed for enhanced oil recovery?
2). Can the selected bacterium Clostridium Tyrobutyricum survive at high salinities and
Self- directing
perform its metabolism to a certain extent?
3). How will pH, gas production and acid production change as a function
increasing salinity? What about the creation of biopolymers?
4). What is the influence of chalk exposed for microbial metabolism?
5). Can we have improved recovery from residual oil using this strain ?
All experiments are performed at temperature 37 oC and ambient pressure
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Self- directing
Salinity effect on bacteria morphology : Note the round shaped bacteria
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Cummulative gas vol (ml)
4000
Pure culture
3000
Adapted strain
2000
1000
0
10
30
50
90
100
Salinity (g/l)
Component
Carbon dioxide
Hydrogen
Nitrogen
Total
% Composition
83.66
16.23
0.11
100.0
Cumulative gas production at different salinity and gas composition
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24 Hours
Rs mol/litre/hour
0.0003
72 Hours
120 Hours
0.00015
0
0
20
40
60
80
100
Salinity (g/l)
Rate of absorption of CO2 in the fermentation media
20
2500
n-butyric acid (mg/L)
2000
40 g/L
1500
50 g/L
60 g/L
70 g/L
1000
80 g/L
90 g/L
500
100 g/L
0
0
40
80
120
Time (Hours)
Acid production at different salinity with Clostridium tyrobactericum
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2500
n-butyric acid ( mg/L)
2000
1500
24 HOURS
72 HOURS
1000
120 HOURS
500
0
4
4.5
5
5.5
6
6.5
7
pH
Acid production and pH variation at different salinity
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Pre-treat porosity
60
Post-treat porosity
Porosity (%)
55
50
45
40
35
30
1
1
2
2
3
3
4
4
5
5
6
6
7
7
Time (weeks)
Porosity modification of 14 chalk samples immersed in bacteria media
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Carbonate rock matrix in microbial media
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Biofilm thickness (cm)
1
0.8
0.6
0.4
0.2
0
0
30
60
90
120
150
Salinity (g/L)
10 days
20 days
30 days
40 days
Biofilm formation at oil water interface
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Parameters
Value
Initial Oil Saturation
120 ml
Residual Oil Saturation after
Water Flooding
33 ml
Nutrient Injected
0.4 PV
Inoculums
0.2 PV
Incubation
37 oC for 7 Days
Secondary Water Flooding
7 PV
Oil Displaced after Secondary
Water Flooding
13 ml
% Oil Recovery after Microbial
Treatment
39%
(I PV=170ml)
Oil recovery from packed sandstone column
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1). The selected bacterium (Clostridium tyrobuyticum) can produced desired
metabolites needed for residual oil recovery thus eliminating use of harsh
chemicals.
2). The microbes can survive and become adapted to conditions with high
salinities. however, their metabolism is decreasing with increasing salinity.
3). Gas production shows a mixture of CO2 and H2 which amounts are decreasing
with increasing salinities. Biofilms are createdup to 100 g/L of salinity.
4). The porosity of chalk increases as a function of time probably because of the
acidic dissolution of the chalk.
5). Residual oil recovery greater than 30% was achieved.
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Thank you for your attention!
Contact Address: Room B115, Niels Bohrs Vej 8
Esbjerg, DK 6700, Denmark
iaj@bio.aau.dk
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