NSERC Industrial Research Chair in Petroleum Microbiology: Research Objectives, Approach, Methods

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1 NSERC Industrial Research Chair in Petroleum Microbiology: Research Objectives, Approach, Methods Gerrit Voordouw Presented in February 2007 during NSERC Site Visit in Calgary

2 % World Energy Consumption - Report#:DOE/EIA-0484(2000)

3 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 H 2 S (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.

4 NSERC IRC Program: Sulfur Cycle Management Improved Production Corrosion Control

5 Landlocked reservoir: PWRI* Sea water injection: PWRI* *Produced water reinjection Sea water has high sulfate concentration (25-30 mm)

6 SRB oil organics SO 4 2- SRB CO 2 H 2 S

7 Souring: a Century-old Problem Sulfur Cycle Management 19th century: City of Amsterdam faces intolerable H 2 S emissions from canals 1895-Beyerinck discovers sulfatereducing bacteria Problem understood: sewage seawater sulfate sulfide Solutions: 1. introduction of sewage systems 2. application of nitrate (early 1900 s) sulfide

8 Fast forward to the late 20th century: Sulfur Cycle Management Can nitrates remove sulfides from oil & gas fields? Nitrate injection in the Coleville reservoir (Kindersley, SK) in 1996 Results: Sulfide down by % Microbial shift from SRB to NRB Major bacterium: strain CVO (Coleville organism), which oxidizes sulfide with nitrate 20 µm

9 Sulfur Cycle Management 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):

10 Nitrate stimulates NRB and NR-SOB, removing H 2 S and eliminating SRB: Sulfur Cycle Management NRB oil organics hnrb NO 3 - SRB CO 2 NO - 2, N 2 oil organics SO 2-4 SRB CO 2 H 2 S Competitive exclusion NR-SOB H 2 S NR-SOB NO 3 - Sulfide removal SO 4 2-, S 0 NO 2 -, N 2

11 Sulfur Cycle Management Methods: bottle tests (microcosms) SRB: hnrb: NR-SOB: (Oil organics, sulfate, PW) sulfide (Oil organics, nitrate, PW) nitrite (sulfide, nitrate, PW) sulfate, nitrite E.g. for SRB: Sulfide (mm) time (days)

12 Distribution of SRB, NRB and NR-SOB in samples obtained from: Baker Petrolite Field Drof Fuhrman Nix Oritupano Dacion Kome Carranza Redfield Encana Medicine Hat Ekofisk Coleville Location Oklahoma, USA Texas, USA Venezuela Venezuela Chad Argentina Iowa, USA Alberta ConocoPhillips/Petrovera Shell NA North Sea SK Ontario Albian Sands Energy Oil sands Alberta Type Oil Oil Oil & gas Oil & gas Oil Oil Gas storage Gas storage Oil Oil Storage tank Oil sand t ( o C) Sample Oil & water Water Water Water Oil & water Water Water Water Water Oil & water Oil & water Water SRB - - NRB - NR-SOB Sulfur Cycle Management

13 Effects of strain CVO and nitrate on SRB metabolism Sulfur Cycle Management Greene, E.A., Hubert, C., Nemati, M., Jenneman, G.E., and Voordouw, G. (2003) Nitrite reductase activity of sulfate-reducing bacteria prevents their inhibition by nitrate-reducing, sulfide-oxidizing bacteria. Environmental Microbiol. 5: nitrite/- nitrite - nitrite/ nitrite 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 by nitrite. J. Bacteriol. 186:

14 Methods: Upflow packed bed bioreactors Sulfur Cycle Management Oil organics sulfate nitrate Concentration (mm) sulfide sulfate Port number acetate sulfide nitrite 0 mm nitrate 5 mm nitrate 10 mm nitrate

15 Required dose of nitrate or nitrite: Sulfur Cycle Management proportional to concentration of oil organics (electron donor) not to the concentration of sulfate (electron acceptor) 25 Nitrate or nitrite dose (mm) Nitrate Oil field organics (mm) Hubert, C., Nemati, M., Jenneman, G., and Voordouw, G. (2003) Containment of biogenic sulfide production in continuous up-flow packed-bed bioreactors with nitrate or nitrite. Biotechnol. Progress. 19:

16 Calculation of nitrate dose from concentration of electron donors in produced water: Sulfur Cycle Management PW composition: Cl: Chloride mg/l 33,463 Br: Bromide mg/l 213 I: Iodide mg/l 64 SO 4 : Sulfate mg/l 2230 NO 3 : Nitrate mg/l 0.0 PO 4 : Phosphate mg/l 0.0 Total Alk: mg/l 3211 NVWA (by titrationqualitative) mg/l 2720 NVWA (by IC-quantitative) mg/l 803 Acetate mg/l Proprionate mg/l Butyrate mg/l Bicarbonate (HCO3) mg/l 491 Weak Base (as NH 4 ): mg/l 355 Ammonium mg/l 282 Lab ph Sp. Gr. 60F: TDS Calculated: mg/l 55, mm nitrate = 2 g/l of calcium nitrate (2000 ppm) = 2 kg/m 3 = 2 tonne/1000 m 3

17 Sulfur Cycle Management Use of STARS (reservoir modelling software from Computer Modelling Group) Inputs: Geology/geophysics reservoir permeabilities Sulfate and electron donor concentrations Nitrate injection rate, relevant microbial activities Output: Sulfide concentrations throughout reservoir

18 Sulfur Cycle Management Objectives/milestones 1. Microbial activities in various fields ( bugs count ) 2. Electron donor concentrations to estimate nitrate dose 3. Adaptation of STARS to incorporate data (1) and (2) 4. Select fields under PWRI for long-term nitrate trial 5. Bioreactor study of souring control in field waters 6. 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

19 Corrosion Control Pitted corrosion interplay of factors that are: Chemical Physical (including metal stress) Microbiological (SRB) SRB contribute by: Localized growth Reduction of sulfate to sulfide

20 Corrosion Control Presence of limited oxygen/nitrate may yield sulfur: SRB: sulfate sulfide excess nitrate limited nitrate nitrite, sulfate nitrogen, sulfur

21 Corrosion Control 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

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23 Corrosion Control How do SRB contribute to metal corrosion? D. vulgaris genome sequence available; information of 1% : Genome sequence Gene array Gene expression pattern Genes needed for pitted corrosion Effect of biocides, nitrite, sulfur/polysulfide

24 Biocides used to control SRB: Corrosion Control CH 3 N R CH 3 benzalkonium chloride Cl - O O glutaraldehyde CH 2 OH CH 2 OH P CH 2 OH CH 2 OH THPS H H R N N H H cocodiamine SO 4 2- COO- O H H formaldehyde HO O OH N O Br bronopol Action of biocides more general Inhibition by nitrite highly specific Combination highly synergistic

25 Sulfide production by an SRB consortium: Corrosion Control Inhibition lack of inhibition Glutaraldehyde (mm) Synergy: 1 mm glutaraldehyde 1mM nitrite as effective as 5 mm glutaraldehyde Nitrite (mm) Patent Application: Greene, E. A., Jenneman, G. and Voordouw, G. Inhibition of biogenic sulfide production via biocide and metabolic inhibitor combination. Filed May 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:

26 Corrosion Control Objectives/milestones 7. Effect of partial souring control on corrosion risk 8. Corrosivity of nitrite/sulfide reaction products 9. Impact of sulfur/polysulfide on SRB-corrosion 10. Synergy between nitrite and biocides 11. Compatibility of nitrate injection and biocide use 12. Corrosion risk during long-term field trials Overall objective/goal: Reducing corrosion risk by preventing formation of sulfur and understanding (in)compatibilities of various treatments

27 Improved Production Two main questions: Can oil be gasified by methanogenic microbes reacting oil components with water? Does continued injection of nitrate or oxygen in an oil field increase production?

28 Conversion of oil to methane: Improved Production DS Zengler et al. (1999) Nature 401:266 - DS (ditch sediment) 4 hexadecane 49 H 2 O 49 methane 15 CO 2 (ΔG = 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?

29 Improved Production Requires an anaerobic methanogenic consortium: 1. Syntrophs: oil components H 2 O acetate H 2 H 2 2. Acetotrophs: acetate methane CO 2 3. Methanogens: H 2 CO 2 methane Overall: Oil components H 2 O methane CO 2 Which oil components? Only low molecular weight aliphatics/aromatics? Can reaction rate/efficiency be improved?

30 Improved Production Methanogenic biodegradation of oil in the subsurface: light oil heavy oil tar sand Density (g/cc) Viscosity (cp) Aliphatics 35% 22% 17% Aromatics 35% 20% 18% Resins 20% 41% 44% Asphaltenes 10% 17% 17% d Principle of SAGD (Steam Assisted Gravity Drainage): Bitumen viscosity much lower at high temperature (10 cp at 200 o C) Allows production from deep tar sands Input: 2-3 barrels of water (as stea /barrel of bitumen

31 Improved Production Oil methanogenesis may accelerate at high temperature: Kaster, K. & Voordouw, G. (2006) Appl. Microbiol. Biotechnol.72: Oil storage tank (50 o C). Methane production blew lid off periodically. Caused by thermophilic, methanogenic consortium ml stoppered bottle 80 ml of gas Time (d) Methanosaeta thermophila

32 Rapid methanogenesis in oil sands tailings ponds: Improved Production Tar sand steam/water solvent Solvent diluted bitumen Sand Water/fines/solvent/bitumen residue Adapted from MacKinnon, AOSTRA J. Res. 1:109 (1989); slide obtained from Julia Foght, UofA

33 Diluent water methane CO 2 Improved Production Up to 10 8 L (70 tonnes) of methane and 3 x 10 7 L (57 tonnes) of CO 2 per day Image courtesy F. Holowenko; slide obtained from Julia Foght

34 Large scale DNA-sequence survey of oil sands microbes Uncovering the Microbial Diversity of the Alberta Oil Sands through Metagenomics: A Stepping Stone for Enhanced Oil Recovery and Environmental Solutions Calgary, September 27 and 28, 2006

35 Preliminary genomics analyses have indicated the presence of methanogenic and NR-SOB activities Improved Production

36 Does continued injection of nitrate or oxygen in an oil field increase production through microbially enhanced oil recovery (MEOR)? Improved Production 1. Sunde, E Method of microbial enhanced oil recovery. Patent WO 92/ Sunde, E. and Torsvik, T Method of microbial enhanced oil recovery. Patent WO 01/33040 Enhanced recovery by injection of aerated sea water Enhanced recovery by injection of nitrate 3. Hitzman et al Recent successes: MEOR using synergistic H 2 S prevention and increased oil recovery systems. SPE paper Oil organics Biomass Nutrients Nitrate or O 2 Biosurfactants

37 Role of Highly Reactive Intermediates (HRI)? Improved Production HRI O 2 O 2 - H 2 O 2 H 2 O NO 3 - NO 2 - NO N 2 O N 2 Complex oil organics (e.g. asphaltenes) accumulate under anaerobic degradation conditions Oxygen/nitrate likely required for biodegradation; mechanism unknown Complex plant polymers (lignin) degraded through HRI

38 Lignin CO 2 White rot fungi Improved Production O 2 Hydrogen peroxide Superoxide (HRI) Degradation products Anaerobic burial oil

39 MEOR through continuous injection of electron acceptors (nitrate, oxygen) and inorganic nutrients may result from: Improved Production Biosurfactants releasing oil Biomass blocking zones of high permeability HRI breaking complex oil organics randomly, reducing M r and viscosity Oil organics Inorganic nutrients Biosurfactants Biomass Nitrate or O 2 HRI

40 Objectives/milestones Improved Production 13. Mechanism of nitrate mediated MEOR 14. Nitrate-mediated conversion of oil sands 15. Isolation of bitumen-degrading microbes 16. Anaerobic conversion of oil to methane 17. Lower methane evolution from tailings ponds 18. Oil sands metagenomics project 19. Applications of the metagenomics database 20. Microbial biotechnology process design Overall objective/goal: Improving conventional/oil sands production (more output with less input) based on understanding of microbial mechanisms to break down oil.

41 Sulfur Cycle Management Improved Production Corrosion Control Supported by: 4 agencies Supported by 8 industrial sponsors