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