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Gerrit Voordouw
Presented in February 2007 during NSERC Site Visit inCalgary
NSERC Industrial Research Chair inPetroleum Microbiology: Research
Objectives, Approach, Methods
World Energy Consumption - Report#:DOE/EIA-0484(2000)
%40
2422
68
Key steps towards sustainable energy future:
• Reduce per capita energy consumption• Increase fraction of renewables to our energy supply• Make extraction and use of fossil fuels as efficient and as
“green” as possible
Oil and gas production is:• increasingly energy intensive and technically demanding• threatened by high H2S (souring), increasing operating costs
Petroleum Microbiology can help by:• reducing souring and corrosion through nitrate injection• contributing to novel enhanced recovery strategies, reducing input of water and energy.
Sulfur CycleManagement
CorrosionControl
ImprovedProduction
NSERC IRC Program:
Landlocked reservoir: PWRI*
*Produced water reinjection
Sea water injection: PWRI*
Sea water has high sulfateconcentration (25-30 mM)
oil organics SO42-
SRB
CO2 H2S
SRB
Sulfur CycleManagement
Souring: a Century-old Problem
• 19th century: City of Amsterdam facesintolerable H2S emissions from canals
• 1895-Beyerinck discovers sulfate-reducing bacteria
• Problem understood: sewage + seawatersulfate → sulfide
• Solutions:
http://www.fotosearch.com/DGT069/cb027636/
sulfide
1. introduction of sewage systems 2. application of nitrate (early 1900’s)
Fast forward to the late 20th century:
Can nitrates remove sulfides from oil & gas fields?
Nitrate injection in the Coleville reservoir (Kindersley, SK) in 1996
20 µm
Results:
• Sulfide down by 40-100%
• Microbial shift from SRB to NRB
• Major bacterium: strain CVO(Coleville organism), whichoxidizes sulfide with nitrate
Sulfur CycleManagement
North Sea:• Continuous, field-wide injection of 100 ppm nitrate.
• Safe, cheap, environmentally friendly method of SRB control
• Data for Gullfaks field (Sunde and Torsvik, 2005):
Sulfur CycleManagement
Nitrate stimulates NRB and NR-SOB, removing H2Sand eliminating SRB:
NO3-
NO2- , N2
oil organics
hNRB
CO2
NRB
oil organics SO42-
SRB
CO2 H2S
SRB
H2S
NR-SOBNO3
-
NR-SOB
SO42-, S0 NO2
- , N2
Competitive exclusion
Sulfide removal
Sulfur CycleManagement
Methods: bottle tests (microcosms)
SRB: (Oil organics, sulfate, PW) → sulfide
hNRB: (Oil organics, nitrate, PW) → nitrite
NR-SOB: (sulfide, nitrate, PW) → sulfate, nitrite
0
4
8
12
16
0 1 2 3 4 5 6 7 8
time (days)
Su
lfid
e (
mM
)
Sulfur CycleManagement
E.g. for SRB:
+++Water30OilArgentinaCarranza
-++Water60Oil & gasVenezuelaOritupano
-+-Oil & water50OilChadKome
-+-Water25Gas storageIowa, USARedfield
+
++NRB
Water
Water
Oil & water
Sample
-+40Oil & gasVenezuelaDacion
++30-35OilTexas, USAFuhrman Nix
-+35OilOklahoma, USADrof
NR-SOBSRBt (oC)TypeLocationField
Distribution of SRB, NRB and NR-SOB in samples obtained from:
+++Oil & water30OilSKColeville
--+Water80OilNorth SeaEkofisk
+++Water25Gas storageAlbertaMedicine HatEncana
ConocoPhillips/Petrovera
-++Oil & water50Storage tankOntarioNAShell
Sulfur CycleManagementBaker Petrolite
Albian Sands Energy+++Water10Oil sandAlbertaOil sands
Effects of strain CVO and nitrate on SRB metabolism Sulfur CycleManagement
Greene, E.A., Hubert, C., Nemati, M., Jenneman, G.E., and Voordouw, G. (2003) Nitrite reductaseactivity of sulfate-reducing bacteria prevents their inhibition by nitrate-reducing, sulfide-oxidizingbacteria. Environmental Microbiol. 5: 607-617
Haveman, S. A., Greene, E. A., Stilwell, C. P., Voordouw, J. K., and Voordouw, G. (2004)Physiological and gene expression analysis of inhibition of Desulfovibrio vulgaris Hildenborough bynitrite. J. Bacteriol. 186: 7944-7950
- nitrite/- nitrite - nitrite/+ nitrite
0.00.51.01.52.02.53.0
0 1 2 3 4 5
0.00.51.01.52.02.53.0
0 1 2 3 4 5
0.00.51.01.52.02.53.0
0 1 2 3 4 5
Con
cent
ratio
n ( m
M)
0 mM nitrate
5 mM nitrate
10 mM nitrate
Port number
Con
cent
ratio
n ( m
M)
1 2 3 4 5
Oil organicssulfatenitrate
acetatesulfidenitrite
sulfide
sulfate
Sulfur CycleManagement
Methods: Upflow packed bed bioreactors
Required dose of nitrate or nitrite:• proportional to concentration of “oil organics” (electron donor)
• not to the concentration of sulfate (electron acceptor)
Nitrate
0
5
10
15
20
25
0 5 10 15 20 25 30
Oil field organics (mM)
Nitr
ate
or n
itrite
dos
e (m
M)
Sulfur CycleManagement
Hubert, C., Nemati, M., Jenneman, G., and Voordouw, G. (2003) Containment ofbiogenic sulfide production in continuous up-flow packed-bed bioreactors withnitrate or nitrite. Biotechnol. Progress. 19: 338-345.
Calculation of nitrate dose from concentration of electrondonors in produced water:
18 mM nitrate = 2 g/L of calcium nitrate (2000 ppm) = 2 kg/m3 = 2 tonne/1000 m3
Sulfur CycleManagement
Cl: Chloride mg/l 33,463
Br: Bromide mg/l 213
I: Iodide mg/l 64
SO4: Sulfate mg/l 2230
NO3: Nitrate mg/l 0.0
PO4: Phosphate mg/l 0.0
Total Alk: mg/l 3211
NVWA (by titration-
qualitative)mg/l 2720
NVWA (by IC-quantitative) mg/l 803
Acetate mg/l 647 60 10.78 8 86.27
Proprionate mg/l 138 74 1.86 14 26.11
Butyrate mg/l 18 86 0.21 20 4.19
Bicarbonate (HCO3) mg/l 491
Weak Base (as NH4): mg/l 355
Ammonium mg/l 282
Lab pH - 7.54
Sp. Gr. Calculated @ 60F: - 1.041
TDS Calculated: mg/l 55,082
116.56 17.93243
PW composition:
Use of STARS (reservoir modelling software fromComputer Modelling Group)
Inputs:Geology/geophysics reservoir permeabilities
Sulfate and electron donor concentrations
Nitrate injection rate, relevant microbial activities
Output:Sulfide concentrations throughout reservoir
Sulfur CycleManagement
Objectives/milestones
1. Microbial activities in various fields (“bugs count”)2. Electron donor concentrations to estimate nitrate dose3. Adaptation of STARS to incorporate data (1) and (2)4. Select fields under PWRI for long-term nitrate trial5. Bioreactor study of souring control in field waters6. Monitor long-term nitrate field trial; enter data into
STARS; determine whether dose predictions correct.
Long term objective/goal:Field →(1, 2) → (3) → advise on souring control through nitrate injection
Sulfur CycleManagement
Pitted corrosion interplay of factorsthat are:
• Chemical• Physical (including metal stress)• Microbiological (SRB)
CorrosionControl
SRB contribute by:• Localized growth• Reduction of sulfate to sulfide
CorrosionControl
limited nitrate
excess nitrate nitrite, sulfate
nitrogen, sulfurSRB: sulfate → sulfide
Presence of limited oxygen/nitrate may yield sulfur:
How rapidly can pitted corrosion lead to failure?
• New steel pipe (7 mm wall thickness)• Put in use in January• Failed in March (i.e. one pit with 100% wall penetration)• Lengthy lawsuit between pipe maker and oil company
CorrosionControl
D. vulgaris genome sequence available; information of 1% :
CorrosionControl
How do SRB contribute to metal corrosion?
Genome sequence → Gene array → Gene expression pattern• Genes needed for pitted corrosion• Effect of biocides, nitrite, sulfur/polysulfide
O O
glutaraldehyde
HH
O
formaldehyde
N
CH3
R
CH3+
Cl-
benzalkonium chloride
P
CH2OH
CH2OH CH2OH
CH2OH+ SO4
2-
THPS
N NR
H
H
H
H
COO-+ +
cocodiamine
NBr
O
O
OH
OH
bronopol
• Action of biocides more general• Inhibition by nitrite highly specific• Combination highly synergistic
Biocides used to control SRB:Corrosion
Control
0
1
2
3
4
5
Glu
tara
ldeh
yde
(mM
)
0 1 2 3 4 5Nitrite (mM)
Sulfide production by an SRB consortium:
Inhibition lack of inhibition
Synergy:1 mM glutaraldehyde + 1mM nitriteas effective as 5 mM glutaraldehyde
CorrosionControl
Patent Application:Greene, E. A., Jenneman, G. and Voordouw, G. Inhibition of biogenic sulfide production via biocide and
metabolic inhibitor combination. Filed May 2004.Publication:Greene, E. A., Brunelle, V., Jenneman, G. E., and Voordouw, G. (2006) Synergistic inhibition of biogenic sulfide
production by combinations of the metabolic inhibitor nitrite and biocides. Appl. Environ. Microbiol.72:7897-7901
CorrosionControl
Objectives/milestones
7. Effect of partial souring control on corrosion risk8. Corrosivity of nitrite/sulfide reaction products9. Impact of sulfur/polysulfide on SRB-corrosion10. Synergy between nitrite and biocides11. Compatibility of nitrate injection and biocide use12. Corrosion risk during long-term field trials
Overall objective/goal:Reducing corrosion risk by preventing formation of sulfur andunderstanding (in)compatibilities of various treatments
ImprovedProduction
Two main questions:
• Can oil be gasified by methanogenic microbesreacting oil components with water?
• Does continued injection of nitrate oroxygen in an oil field increase production?
Conversion of oil to methane:
Zengler et al. (1999) Nature 401:266
(ditch sediment)4 hexadecane + 49 H2O → 49 methane + 15 CO2
(ΔG = -1500 kJ/mol of hexadecane)
Oil can be biodegraded with water Explains how subsurface oil is biodegraded Selective removal of light components leaves viscous/heavy oil Athabasca oil sands:
Endpoint of this methanogenic transformation?
+ DS
- DS
ImprovedProduction
Requires an anaerobic methanogenic consortium:
1. Syntrophs: oil components + H2O → acetate + H2 + H2 O
2. Acetotrophs: acetate → methane + CO2
3. Methanogens: H2 + CO2 → methane____________________________________________________________________
Overall: Oil components + H2O → methane + CO2
• Which oil components?• Only low molecular weight aliphatics/aromatics?• Can reaction rate/efficiency be improved?
ImprovedProduction
Methanogenic biodegradation of oil in the subsurface:
light oil → heavy oil → tar sandDensity (g/cc) 0.8-0.9 1.0-1.004 1.02Viscosity (cp) 103-104 104-105 105-107
Aliphatics 35% 22% 17%Aromatics 35% 20% 18%Resins 20% 41% 44%Asphaltenes 10% 17% 17%
ImprovedProduction
Principle of SAGD (Steam Assisted Gravity Drainage):• Bitumen viscosity much lower at high temperature (10 cP at 200 oC)• Allows production from deep tar sands• Input: 2-3 barrels of water (as steam/barrel of bitumen
d
Oil methanogenesis may accelerate at high temperature:Kaster, K. & Voordouw, G. (2006) Appl. Microbiol. Biotechnol.72:1308-1315
Oil storage tank (50 oC).Methane production blew lid off periodically.Caused by thermophilic, methanogenic consortium
20
40
60
80
100
ml
of
gas
15 20 25 30
Time (d)
20
40
60
80
100
ml
of
gas
15 20 25 30
Time (d) Methanosaeta thermophila
100 ml stoppered bottle
ImprovedProduction
Adapted from MacKinnon, AOSTRA J. Res. 1:109 (1989); slide obtained from Julia Foght, UofA
Rapid methanogenesis in oil sands tailings ponds:
Tar sandsteam/water
solvent
Solvent diluted bitumen
Sand
Water/fines/solvent/bitumen residue
ImprovedProduction
Diluent + water→methane + CO2
Image courtesy F. Holowenko; slide obtained from Julia Foght
Up to 108 L (70 tonnes) of methane and 3 x 107 L (57 tonnes) of CO2 per day
ImprovedProduction
Uncovering the Microbial Diversity of the Alberta Oil Sands through Metagenomics: AStepping Stone for Enhanced Oil Recovery and Environmental Solutions
Calgary, September 27 and 28, 2006
Large scale DNA-sequence survey of oil sands microbes
Preliminary genomics analyses have indicated the presence ofmethanogenic and NR-SOB activities
ImprovedProduction
Does continued injection of nitrate or oxygen in an oilfield increase production through microbially
enhanced oil recovery (MEOR)?
Oil organics
Nutrients
Nitrate or O2
Biomass
Biosurfactants
1. Sunde, E. 1992. Method ofmicrobial enhanced oil recovery.Patent WO 92/13172.
2. Sunde, E. and Torsvik, T. 2001.Method of microbial enhanced oilrecovery. Patent WO 01/33040
Enhanced recovery by injectionof aerated sea water
Enhanced recovery by injectionof nitrate
3. Hitzman et al. 2004. Recent successes: MEOR using synergistic H2Sprevention and increased oil recovery systems. SPE paper 89543.
ImprovedProduction
• Complex oil organics (e.g. asphaltenes) accumulate underanaerobic degradation conditions
• Oxygen/nitrate likely required for biodegradation; mechanismunknown
• Complex plant polymers (lignin) degraded through HRI
O2 → O2- → H2O2 → H2O
NO3- → NO2
- → NO → N2O → N2
HRI
ImprovedProductionRole of Highly Reactive Intermediates (HRI)?
LigninWhite rot fungi
Hydrogen peroxideSuperoxide
(HRI)
Degradationproducts
O2
Anaerobic burial oil
CO2Improved
Production
MEOR through continuous injection of electron acceptors(nitrate, oxygen) and inorganic nutrients may result from:
• Biosurfactants releasing oil• Biomass blocking zones of high permeability• HRI breaking complex oil organics randomly, reducing Mr and viscosity
Oil organics
Inorganic nutrients
Nitrate or O2
Biomass
Biosurfactants
HRI
ImprovedProduction
13. Mechanism of nitrate mediated MEOR14. Nitrate-mediated conversion of oil sands15. Isolation of bitumen-degrading microbes16. Anaerobic conversion of oil to methane17. Lower methane evolution from tailings ponds18. Oil sands metagenomics project19. Applications of the metagenomics database20. Microbial biotechnology process design
ImprovedProduction
Objectives/milestones
Overall objective/goal:Improving conventional/oil sands production (more output withless input) based on understanding of microbial mechanisms tobreak down oil.
Supported by: 4 agencies
Supported by 8 industrial sponsors
Sulfur CycleManagement
CorrosionControl
ImprovedProduction
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