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

2 Introduction Enhanced Oil Recovery Methods and why are they needed? Microbial Enhanced Oil Recovery Experimental Study (Objectives) Results of Laboratory Investigations Conclusions/Further Works

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 % oil productions While additional 15-25% can be recovered by secondary methods such as water injection leaving behind about % 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) 3

4 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

5  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

6

7 After Janshekar, 1985

 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. Microbial Enhanced Oil Recovery (MEOR) is a technology using micro-organisms to facilitate, increase or extend oil production from reservoir. 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. Selective Plugging 2. Hydrocarbon Chain Degrading Bacteria 3. 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 , 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

The microbes degrade hydrocarbons to the following components A large group of bacteria is able to cut hydrocarbon chains thus decreasing the viscosity of oil.

Viscous Oil (Bokor Field Malaysia) Before TreatmentAfter Treatment Over past 5 months (post MEOR) Production rate152 b/d334 b/d Water cut75 %45 % Heavy oil field in Western Siberia, Russia, January, 2006 Before TreatmentAfter Treatment For a Period 3 Months Production rate5 - 7 m3/h m3/h (mostly m3/h) Water cut48 %25 % Quality of oil-improved

Lazar et al., 2007:Microbial Enhanced Oil Recovery

 Microbes replicate -process is self sustaining  Eliminates logistical hassle  Find their own carbon source in the reservoir  Create recovery enhancing chemicals where needed  A Rather cheap method compared to CO2 injection 15 Self- propagating Self- directing

 High salinity  High temperature  High pressure in oil reservoirs  pH  Pore geometry The big question is how to find the right candidate! 16

17 Self- directing 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 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 o C and ambient pressure

18 Self- directing Salinity effect on bacteria morphology : Note the round shaped bacteria

19 Cumulative gas production at different salinity and gas composition

20 Rate of absorption of CO 2 in the fermentation media

21 Acid production at different salinity with Clostridium tyrobactericum

22 Acid production and pH variation at different salinity

23 Porosity modification of 14 chalk samples immersed in bacteria media

24 Carbonate rock matrix in microbial media

25 Biofilm formation at oil water interface

26 Oil recovery from packed sandstone column ParametersValue Initial Oil Saturation120 ml Residual Oil Saturation after Water Flooding 33 ml Nutrient Injected0.4 PV (I PV=170ml) Inoculums0.2 PV Incubation37 o C for 7 Days Secondary Water Flooding7 PV Oil Displaced after Secondary Water Flooding 13 ml % Oil Recovery after Microbial Treatment 39%

27 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 CO 2 and H 2 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.

28 Contact Address: Room B115, Niels Bohrs Vej 8 Esbjerg, DK 6700, Denmark Thank you for your attention!