Microbial Enhanced Oil Recovery-Laboratory Experiments with a ...

Microbial Enhanced Oil Recovery: A Technology Tool for Sustainable

Development of Residual Oil

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

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Presentation Layout

• Introduction

•Enhanced Oil Recovery Methods and why are they needed?

• Microbial Enhanced Oil Recovery

• Experimental Study (Objectives)

• Results of Laboratory Investigations

• Conclusions/Further Works

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• 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 35-55 % 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)

Introduction

www.energyinsights.net

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Second and Third Generation EOR Methods

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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What is microbial enhanced oil recovery (MEOR)?

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

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Schematic of MEOR Technology

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MEOR MechanismsBioproduct Effect Acids Biomass Gases (CO2, CH4, H2) Solvents Surface-active agents Polymers

Modification of reservoir rock Improvement of porosity and permeability 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 Reservoir repressurization Oil swelling Viscosity reduction Increase permeability due to solubilization of carbonate rocks by CO2 Dissolving of oil Lowering of interfacial tension Emulsification Mobility control Selective and non-selective plugging

After Janshekar, 1985

Microbial Enhanced Oil Recovery (MEOR)

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

Cases of MEOR Application

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 Bacteria3. Cyclic Microbial Recovery

1. Selective Plugging Recovery:

Znamenskiy Field, Russia:

• Microbes of activated sludge andbio-stimulators application on the last stage of carbonate rock field development.

• Totally during 1996-2002, 68injectors 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.

2. Microbiological Stimulation for Oil RecoveryStimulating naturally occurring bacteria

that feed onoil to create conditions that release

residual oil fromthe 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 Statoilinto the Norne field to free oil clinging to thereservoir rock and enhanced recovery

3. Hydrocarbon Chain Degrading Bacteria

The microbes degrade hydrocarbons to thefollowing components

A large group of bacteria is able to cut hydrocarbon chains thus decreasing the viscosity of oil.

3. Hydrocarbon Chain Degrading Bacteria

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 %

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 16-17

m3/h) Water cut 48 % 25 %

Quality of oil - improved

Cases of MEOR Application Worldwide

Lazar et al., 2007:Microbial Enhanced Oil Recovery

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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

The Best Part of MEOR

Self-propagating

Self- directing

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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!

Limiting Factors for MEOR

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Experimental Study (Objectives)

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 oC and ambient pressure

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1. Result of microbial Adaptation

Self- directing

Salinity effect on bacteria morphology : Note the round shaped bacteria

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2. Results of gas production

Cumulative gas production at different salinity and gas composition

10 30 50 90 1000

1000

2000

3000

4000

Pure culture

Adapted strain

Salinity (g/l)

Cum

mul

ativ

e ga

s vo

l (m

l)

Component % Composition Carbon dioxide 83.66

Hydrogen 16.23 Nitrogen 0.11

Total 100.0

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Result

Rate of absorption of CO2 in the fermentation media

0 20 40 60 80 1000

0.000150000000000001

0.000300000000000001

24 HoursExponential (24 Hours)72 HoursExponential (72 Hours)120 HoursExponential (120 Hours)

Salinity (g/l)

Rs m

ol/li

tre/

hour

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3. Results of acid production

Acid production at different salinity with Clostridium tyrobactericum

0 40 80 1200

500

1000

1500

2000

2500

40 g/L50 g/L60 g/L70 g/L80 g/L90 g/L100 g/L

Time (Hours)

n-bu

tyric

aci

d (m

g/L)

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Result

Acid production and pH variation at different salinity

4 4.5 5 5.5 6 6.5 70

500

1000

1500

2000

2500

24 HOURSLinear (24 HOURS)72 HOURSLinear (72 HOURS)120 HOURSLinear (120 HOURS)

pH

n-bu

tyric

aci

d (

mg/

L)

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4. Result of microbial fluid-rock interactions

Porosity modification of 14 chalk samples immersed in bacteria media

1 1 2 2 3 3 4 4 5 5 6 6 7 730354045505560

Pre-treat porosity Post-treat porosity

Time (weeks)

Poro

sity

(%

)

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Result

Carbonate rock matrix in microbial media

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5. Results biofilm formation

Biofilm formation at oil water interface

30 60 90 120 1500

0.2

0.4

0.6

0.8

1

10 days 20 days 30 days 40 days

Salinity (g/L)

Biofi

lm t

hick

ness

(cm

)

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6. Results Oil Recovery

Oil recovery from packed sandstone column

Parameters ValueInitial Oil Saturation 120 ml

Residual Oil Saturation after Water Flooding

33 ml

Nutrient Injected 0.4 PV (I PV=170ml)

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%

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Conclusions

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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