Microbial Enhanced Oil Recovery Process

MICROBIAL

ENHANCED OIL RECOVERY

PROCESS (MEOR)

Detailed Documentation & Appraisal Of:

BY

Miss Ezeanya, Chinyere Charity

EZEANYA, CHINYERE CHARITY (BSc. Hons)

(2010)

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Microbial Enhanced Oil Recovery (MEOR)

ABSTRACT

Enhanced oil recovery (EOR) refers to the recovery of oil that is left behind

after primary and secondary recovery methods have either been exhausted

or no longer economical.

Since 1946 more than 400 patents on MEOR have been issued, but none has

gained acceptance by the oil industry. Most of the literature on MEOR is

from laboratory experiments.

Primary recovery usually only accesses 30 to 35 per cent of the original oil

in place (OOIP).

Secondary and tertiary recovery methods may net a further 15 to 25 per

cent OOIP, leaving 30 to 55 per cent OOIP left behind as irrecoverable or

irreducible oil in the reservoir.

Microbial enhanced oil recovery (MEOR) technology targets the remaining

oil and aims at enabling production of 80 to 85 per cent of OOIP.

There are different modes of Enhanced Oil Recovery (EOR) methods. These

are: Chemical methods, Gas flooding, Microbial processes, Thermal

processes, Novel methods and Computer simulation.

Microbial enhanced oil recovery (MEOR) method relies on microbes to

ferment hydrocarbons and produce a by-product that is useful in the

recovery of oil. MEOR functions by channeling oil through preferred

pathways in the reservoir rock. This is done by closing/plugging off small

channels and forcing the oil to migrate through the larger pore spaces. While

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it is clear that biocatalysis performed by microbes may promote beneficial

chemical reactions such as the production of biosurfactants in a very specific

and energy-efficient manner, a sound understanding of the underlying

principles is important to predict site-specific effects of microbial activity on

fluid flow in porous media and hence on the efficiency of oil production.

Stimulating bacterial growth at an oil/water interface causes a substantial

reduction in interfacial tension (IFT), which in turn can help to achieve

improved oil recovery (IOR).

MEOR has two distinct advantages: microbes do not consume large

amounts of energy and the use of microbes is not dependent on the price of

crude oil, as compared with other EOR processes.

The Titan Process of MEOR is a dynamic, new and unique form of

Microbial Enhanced Oil Recovery (MEOR). The Titan Process injects

special nutrients into a reservoir which change the skin characteristics of the

individual microbes living in the reservoir biofilm and induces the microbes

to become oleophilic [oil-loving] and attach themselves to oil droplets. The

microbes then dislodge and uniquely break down the trapped oil within the

pore spaces into smaller droplets. These smaller droplets can now more

easily pass through the pore spaces of the reservoir and become recoverable.

A gentle emulsion is also formed by a unique combination of oil, water and

energized microbes. This emulsion blocks thief zones, channelling and

fingering, thereby allowing for greatly improved sweep efficiency and a

substantial reduction to the water cut.

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The prime consideration with MEOR is, therefore, how much additional oil

can be produced from reservoirs by stimulating the growth of indigenous or

injected bacteria.

TABLE OF CONTENT

PAGES

ABSTRACT 1

TABLE OF CONTENT 3

CHAPTER ONE

Enhanced Oil Recovery (EOR) Process 5

Modes of EOR 7

Chemical Methods 7

Gas Flooding 8

Thermal Process 9

Computer Simulation 10

Oil Recovery Factor 10

CHAPTER TWO

Description And History of MEOR 11

Description 11

History 12

Current Status of MEOR 14

CHAPTER THREE

The Science of MEOR 15

Biotechnology and MEOR 17

CHAPTER FOUR

Classification of MEOR 19

Ventures Working in MEOR 19

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Microbial Flooding Recovery 21

CHAPTER FIVE

Mechanisms of Microbial Enhanced Oil Recovery 25

CHAPTER SIX

Types of MEOR 28

CHAPTER SEVEN

The Titan Process of MEOR 30

Avoiding Complexities 31

No Oxygen Required 32

CHAPTER EIGHT

Advantages of MEOR 35

CHAPTER NINE

Challenges 37

Environmental factors 37

Grounds of Failure 37

CHAPTER TEN 41

Conclusion

CHAPTER ELEVEN

References 44

Profile 48

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CHAPTER ONE

ENHANCED OIL RECOVERY (EOR) PROCESS

Discoveries of new reservoirs, is a high-risk business that companies

undertake hoping to achieve a correspondingly high return. Sometimes they

are successful but more often they are not. In many cases, increasing the

recovery of oil from existing reservoirs can be less expensive than

exploration and less risky as well. The reservoir will have already been

partially developed therefore wells and surface production facilities are

already in place.

Enhanced oil recovery (EOR) refers to the recovery of oil that is left behind

after primary and secondary recovery methods are either exhausted or no

longer economical. EOR is a highly–individualized process that is specific

to each field’s characteristics.

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Primary production is the first oil out, the “easy” oil. In primary recovery

process, when a well is been drilled and completed in a hydrocarbon–

bearing zone, the natural pressures at that depth will cause the oil to flow

through the rock or sand formation toward the lower pressure well bore,

where it is lifted to the surface. Primary recovery is the least expensive

method of extraction, since it uses natural forces to “move” the oil.

Secondary recovery methods are used when there is insufficient

underground pressure to move the remaining oil. The most common

technique, water flooding, utilizes injector wells to introduce large volumes

of water under pressure into the hydrocarbon–bearing zone. As the water

flows through the formation toward the producing well bore, it sweeps some

of the oil it encounters along with it. Upon reaching the surface, the oil is

separated out for sale and the water is re-injected (Cano Petroleum).

Tertiary recovery method is implemented when water flooding for

secondary recovery reaches a point when production is no longer cost–

effective. This is the surfactant–polymer (SP) flooding. The chemical

components of the SP process, used alone or combined are mixed with water

which is injected into the formation as in a traditional water flood.

Surfactant cleans the oil off the rock – much like dish soap cuts the grease in

a frying pan; Polymer spreads the flow through more of the rock.

MODES OF ENHANCED OIL RECOVERY

Several methods are employed in Enhanced Oil Recovery process. These

are:

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Chemical Methods

Chemical methods focus mainly on alkaline–surfactant–polymer (ASP)

processes that involve the injection of micellar–polymers into the reservoir.

Chemical flooding reduces the interfacial tension between the in–place

crude oil and the injected water, allowing the oil to be produced. Micellar

fluids are composed largely of surfactants mixed with water. Chemical

flooding technologies are subdivided into alkaline–surfactant–polymer

processes, polymer flooding, profile modification, and water shut off

methods.

Gas Flooding

Gas flooding technologies primarily use carbon dioxide flooding as a

method to produce more oil from the reservoir by channeling gas into

previously-bypassed areas. Carbon dioxide flooding technologies,

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experiment with a number of foams, gels, and thickening agents to improve

sweep efficiency. In the past decade flooding with nitrogen gas, flue gas,

and enriched natural gas have also shown some beneficial results by

increasing recovery when used to re–pressure reservoirs. Nitrogen and flue

gas may be useful in areas where CO2 is not economically available for use

(Cano Petroleum).

Thermal Processes

Heavy oil is recovered by introducing heat into the reservoir through

thermally controlled processes. Steam flooding and in situ combustion or air

injection are the most frequently-used thermal recovery methods. Steam

flooding is used extensively in the heavy oil reservoirs in California. Steam

flooding is conducted by injecting steam into reservoirs that are relatively

shallow, permeable, and thick, and contain moderately viscous oil. The

dominant mechanism in thermal recovery by steam is the reduction in the

viscosity of the oil, allowing flow to the well bore. In situ combustion

introduces heat in the reservoir by a process of injection air and down hole

ignition to burn portions of the oil to displace additional oil. The combustion

front is sustained and propagated through continuous injection of air into the

reservoir. Premature breakthrough of the combustion front contributes to

operational problems. Both steam flooding and in situ combustion have high

surface facility costs and require special safety measures (Cano

Petroleum).

Novel Methods

Novel methods include down hole electric heating, microwave heating,

seismic wave stimulation, and wetting ability reversal. Of these, seismic 9


stimulation has met with success in Russia and is currently being tested in

the U.S. Wetting ability studies to influence oil-wet and water-wet

conditions and to design a brine to reverse wetting ability show promise for

future EOR recovery.

Computer Simulation

Reservoir simulation is advancing rapidly with improved computing

capabilities. Reservoir simulators are useful in the design and prediction of

performance in EOR projects. Improved hardware and software programs

are becoming available that include EOR applications. The development of

computer clusters allows high speed data processing at relatively low cost.

Current goals are to develop software and user guides that predict reservoir

properties suitable to independent operators. Reservoir simulation should be

considered as a tool in any enhanced oil recovery project.

Microbial Processes

Microbial enhanced oil recovery refers to the use of microorganisms to

retrieve additional oil from existing wells, thereby enhancing the petroleum

production of an oil reservoir. In this technique, microorganisms are

introduced into oil wells to produce harmless by-products, such as slippery

natural substances or gases, all of which help propel oil out of the well.

Because these processes help to mobilize the oil and facilitate oil flow, they

allow a greater amount to be recovered from the well. MEOR is used in the

third phase of oil recovery from a well, known as tertiary oil recovery.

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Recovering oil usually requires two to three stages, which are briefly

described as follows:

Stage 1: Primary Recovery – 12% to 15% of the oil in the well is

recovered without the need to introduce other substances into the well.

Stage 2: Secondary Recovery – The oil well is flooded with water or other

substances to drive out an additional 15% to 20% more oil from the well.

Stage 3: Tertiary Recovery – This stage may be accomplished through

several different methods, including MEOR, to additionally recover up to

11% more oil from the well.

Oil Recovery Factor: This is also called overall hydrocarbon displacement

efficiency. This is the volume of hydrocarbon displaced divided by the

volume of hydrocarbon in place at the start of the process measured at the

same conditions of pressure and temperature.

Where,

Ev= macroscopic (volumetric) displacement efficiency; and

ED= microscopic (volumetric) hydrocarbon displacement efficiency.

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CHAPTER TWO

DESCRIPTION AND HISTORY OF MEOR

DESCRIPTION

Microbial Enhanced Oil Recovery (MEOR) is a biological based

technology that manipulates function or structure, or both, of microbial

environments existing in oil reservoirs. The ultimate aim of MEOR is to

improve the recovery of oil entrapped in porous media while increasing

economic profits. As stated earlier, MEOR is a tertiary oil extraction

technology allowing the partial recovery of the commonly residual two-

thirds of oil, thus increasing the life of mature oil reservoirs.

MEOR is a multidisciplinary field incorporating, among others: geology,

chemistry, microbiology, fluids mechanics, petroleum engineering,

environmental engineering and chemical engineering. The microbial

processes proceeding in MEOR can be classified according to the oil

production problem in the field:

well bore clean up removes mud and other debris blocking the

channels where oil flows through;

well stimulation improves the flow of oil from the drainage area into

the well bore; and

enhanced water floods increase microbial activity by injecting

selected microbes and sometimes nutrients. From the engineering

point of view, MEOR is a system integrated by the reservoir,

microbes, nutrients and protocol of well injection.

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The microbes in MEOR are typically hydrocarbon-utilizing, non-pathogenic

micro-organisms that are naturally found in petroleum reservoirs(in situ) or

are introduced (ex situ). Injected nutrients, together with indigenous or

added microbes, promote in situ microbial growth and generation of

products which mobilize additional oil and move it to producing wells

through reservoir depressurization, interfacial tension/oil viscosity

reduction, and selective plugging of the most permeable zones.

Alternatively, the oil-mobilizing microbial products may be produced by

fermentation and injected into the reservoir.

HISTORY

This technology depends on the physicochemical properties of the reservoir

in terms of salinity, pH, temperature, pressure and nutrient availability. Only

bacteria are considered promising candidates for microbial enhanced oil

recovery. Moulds, yeasts, algae, protozoa are not suitable due to their size or

inability to grow under the conditions present in the reservoirs. Many

petroleum reservoirs have high Nacl concentration and require the use of

bacteria which can tolerate these conditions (Jonathan et. al 2003).

The concept of Microbial Enhanced Oil Recovery (MEOR) was proposed

nearly 80 years ago. It has only received limited attention due to the

scepticism of potential users. The main concern of sceptics was the lack of

scientific proof that the purported results are caused by micro organisms.

The concept of using micro organisms to enhance oil recovery, MEOR, was

first proposed in 1926 by Beckman but, it was not until the 1940's that the

concept was actively researched by ZoBell and his colleagues. Since that 13


time, multiplicity of microbiological technologies has been developed to

enhance oil recovery.

The various stages of development of MEOR are outline below:

First Stage: Initial ( to 1975)

In 1895, Miyoshi first reported the growth of a mould culture on n-alkanes.

In 1926, Bastin did the first extensive microbiological study describing the

widespread presence of SRB in oil-producing wells. At the same year,

Beckman suggested that microorganisms could be used to release oil from

porous media7. Later in 1946, as the most important founder of MEOR,

ZoBell patented a process for the secondary recovery of petroleum, using

anaerobic, hydrocarbon-utilizing, sulfate-reducing bacteria such as

Desulfovibrio species in situ8. The first field test was carried out in the

Lisbon field, Union County, AR in 1954. Kuznetsov et al. found that

bacteria discovered in some oil reservoirs in the Soviet Union produced 2

gm of CO2 per day per ton of rock, in 1963.

Second Stage: Developmental (1975~1996)

From 1970s to late 1990s, MEOR research was boosted by the petroleum

crisis and later became a scientific substantiated EOR method. Many

international meetings were periodically organized on the MEOR topic and

proceedings volumes with the advances in the knowledge and practice of

MEOR have been publi

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Third Stage: Rapid (1996~)

From late 1990s, modern biological methods began to be applied on the

MEOR research, such as Molecular Ecological Technique of Microbes,

Protoplast Fusant Technology, and Recombination DNA Technology11,1 2.

Current Status of MEOR

The research of MEOR has been done worldwide, and most of oil producing

countries have applied this technology into oil fields for pilot tests. Recently

this technology has been widely used in oilfields of China, such as Daqing,

Shengli, Jilin, Dagang, Liaohe, Henan, Changqing, Xinjiang, and Qinghai.

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CHAPTER THREE

THE SCIENCE OF MEOR

The microorganisms used in MEOR can be applied to a single oil well or to

an entire oil reservoir. They need certain conditions to survive, so nutrients

and oxygen are often introduced into the well at the same time. MEOR also

requires that water be present. Microorganisms grow between the oil and the

well's rock surface to enhance oil recovery by the following methods:

Reduction of oil viscosity – Oil is a thick fluid that is quite viscous,

meaning that it does not flow easily. Microorganisms help break down the

molecular structure of crude oil, making it more fluid and easier to recover

from the well.

Production of carbon dioxide gas – As a by-product of metabolism,

microorganisms produce carbon dioxide gas. Over time, this gas

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accumulates and displaces the oil in the well, driving it up and out of the

ground.

Production of biomass – When microorganisms metabolize the nutrients

they need for survival, they produce organic biomass as a by-product. This

biomass accumulates between the oil and the rock surface of the well,

physically displacing the oil and making it easier to recover from the well.

Selective plugging – Some microorganisms secrete slimy substances called

exopolysaccharides to protect themselves from drying out or falling prey to

other organisms. This substance helps bacteria plug the pores found in the

rocks of the well so that oil may move past rock surfaces more easily.

Blocking rock pores to facilitate the movement of oil is known as selective

plugging.

Production of biosurfactants – Microorganisms produce slippery

substances called surfactants as they breakdown oil. Because they are

naturally produced by biological microorganisms, they are referred to as

biosurfactants. Biosurfactants act like slippery detergents, helping the oil

move more freely away from rocks and crevices so that it may travel more

easily out of the well.

Case Study: An Exopolysaccharide Called Xanthan

The Xanthomans campestris bacteria produces a gummy substance called

Xanthan. Because Xanthan is molecularly composed of many different

sugars and is externally secreted, it is known as an exopolysaccharide.

Xanthan may be used in MEOR to lubricate oil drills, to help remove rocks

from the drill site, and to compensate for decreased pressure in depleted oil

wells, thereby facilitating the movement of oil up and out of the well.

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BIOTECHNOLOGY AND MEOR

MEOR is a direct application of biotechnology. It uses biological materials,

such as bacteria, microorganisms, and their products of metabolism to

facilitate the movement of oil out of a well, thereby enhancing oil recovery.

Other applications of biotechnology in MEOR include genetic engineering

techniques and recombinant DNA technology, which are used to develop

strains of bacteria with improved oil recovery traits.

By inserting genes from one type of bacteria into another, scientists may

combine two desirable genetic traits into one microorganism. For example,

the temperature within an oil well is often too high for most microorganisms

to survive. By inserting a gene that codes for a bacteria's ability to aid oil

recovery into the genome of an existing bacteria that can survive under high

temperatures, scientists may produce microorganisms that can both survive

the heat of an oil well and also help retrieve oil. On their own, each bacteria

lacks a trait necessary for oil recovery operations, but when combined

through genetic engineering, the bacteria become integral to MEOR.

Current Research Areas

The environmental conditions in an oil well make it very difficult for

bacteria to survive, and those that do often have a decreased ability to carry

out the chemical processes needed to enhance oil recovery. Researchers are

working to create strains of bacteria that are better able to survive such harsh

conditions but still retain the ability to carry out the chemistry needed for

MEOR. Genetic engineering is being used to develop microorganisms that

can not only live in the high temperatures of an oil well, but can also subsist

on inexpensive nutrients, remain chemically active, and produce substantial

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amounts of biosurfactants. Some researchers are developing bacteria that

can be grown on inexpensive agricultural waste material, which is abundant

in supply and is environmentally friendly.

Sustainable Development and MEOR

As MEOR reduces or eliminates the need to use harsh chemicals during oil

drilling, it is an environmentally compatible method of carrying out tertiary

oil recovery. MEOR will become increasingly economically feasible as

genetic engineering develops more effective microbial bacteria that may

subsist on inexpensive and abundant nutrients. Methods for developing and

growing MEOR bacteria are improving, thereby lowering production costs

and making it a more attractive alternative to traditional chemical methods

of tertiary oil recovery.

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CHAPTER FOUR

CLASSIFICATION OF MEOR

MODELS

Developing mathematical models for MEOR is very challenging since physical, chemical and biological factors need to be considered.

Published MEOR models are composed of transport properties, local equilibrium, breakdown of filtration theory and physical straining. Such models are so far simplistic and they were developed based on:

(A) Fundamental conservation laws, cellular growth, retention kinetics of biomass, and biomass in oil and aqueous phases. The main aim was to predict porosity retention as a function of distance and time.

(B) Filtration model to express bacterial transport as a function of pore size; and relate permeability with the rate of microbial penetration by applying Darcy’s law.

VENTURES WORKING IN MEOR

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Mainly, MEOR is classified as surface MEOR and underground MEOR

based on the place where microorganisms work. For surface MEOR,

biosurfactand (Rhamnolipid), biopolymer (xanthan gum), and enzyme are

produced in the surface facilities. These biological products are injected into

the target place in the reservoirs as chemical EOR methods. While, for

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underground MEOR, microorganisms, nutrients and/or other addictives are

injected into the reservoir and let them sustain, grow, metabolize, and

ferment underground.

Based on the source of microorganisms, underground MEOR is categorized

into in-situ MEOR and indigenous MEOR. While according to procedures

of processes, underground MEOR is sorted as:

Cyclic Microbial Recovery (Huff and Puff, Single Well Stimulation)

Wax Removal and Paraffin Inhibition (Wellbore Cleanup)

Microbial Flooding Recovery

Selective Plugging Recovery

Acidizing/Fracturing

Cyclic Microbial Recovery

A solution of microorganisms and nutrients is introduced into an oil

reservoir during injection. The injector is then shut in for an incubation

period allowing the microorganisms to produce carbon dioxide gas and

surfactants that help to mobilize the oil. The well is then opened and oil and

products resulting from the treatment are produced. This process may be

repeated. The figure here illustrates this technology.

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Illustration of Cyclic Microbial Recovery

MICROBIAL FLOODING RECOVERY

Recovery by this method utilizes the effect of microbial solutions on a

reservoir. The reservoir is usually conditioned by a water preflush, then a

solution of microorganisms and nutrients is injected. As this solution is

pushed through the reservoir by drive water, it forms gases and surfactants

that help to mobilize the oil. The resulting oil and product solution is then

pumped out through production wells. The figure below diagrammatizes this

technology.

Illustration of Microbial Flooding Recovery

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Microbial growth can be either within the oil reservoir (in situ) or on the

surface where the byproducts from microbes grown in vats, are selectively

removed from the nutrient media, and then injected into the reservoir.

The prime consideration with MEOR is how much additional oil can be

produced from reservoirs by stimulating the growth of indigenous or

injected bacteria. This is accomplished by adding nutrients to injection

water.

When certain types of microbes are stimulated in core samples of reservoir

sandstone in the laboratory, they improve oil production by mobilising

residual oil trapped in the pore space.

This is probably because the bacteria induce changes in the interfacial

tension (IFT) between the oil and the water, and possibly also because they

cause a change in wetting properties.

Researchers at Statoil and Norway’s Sintef foundation have made a

significant advance by quantitatively monitoring changes in IFT at a simple

oil/water interface using an advanced laser-light scattering technique.

Microbially induced reduction in interfacial tension with time.

The graph of IFT versus time shows that the bacteria induced a 6,000-fold

exponential reduction in the IFT.

Displacement of Oil by Metabolites of Inoculated Bacteria Grown In Situ

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Injection of bacterial suspensions followed by nutrients to produce

biopolymer and microbial itself, which may plug the high permeability zone

in the reservoir. The reduction of permeability would change the inject

profile and achieve conformance control.

This development is thought to occur because the bacterial growth requires

both carbon from the oil and nutrients from the formation water. Since they

occur in the water, the bacteria need to penetrate the oil/water interface to

access the carbon.

They achieve this by producing a biosurfactant (tenside), which reduces the

IFT and thus lowers the energy needed for breakthrough.

Statoil is thought to be the only company in the world using MEOR on an

offshore field, in this case Norne in the Norwegian Sea.

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CHAPTER FIVE

MECHANISMS OF MICROBIAL ENHANCED OIL RECOVER

(MEOR)

An approach to apply MEOR technology considers primarily:

a. microbiological studies to select the appropriate microorganisms and

b. mobilization of oil in laboratory experiments before oil field

application. Ten bacterial strains identified as Pseudomonas

aeruginosa, Bacillus licheniformis, Bacillus brevis, Bacillus

polymyxa, Micrococcus varians, Micrococcus sp. and two Vibrio

species demonstrated potential to be used in oil recovery. Strains of

B. licheniformis and B. polymyxa produced the most active

surfactants and proved to be the most anaerobic and thermo tolerant

among the selected bacteria. Micrococcus and B. brevis were the most

salt-tolerant and polymer producing bacteria, respectively, whereas

Vibrio sp. and B. polymyxa strains were the most gas-producing

bacteria.

The mechanisms by which the bacteria can improve the oil recovery are as

follows:

(a) Biodegradation of Crude Oil: A proposed mechanism of MEOR is

utilization of bacteria that can degrade crude oil and consume its heavy

fractions. As a result of this process, oil becomes a lighter and more 26


valuable product as a result of a decrease in viscosity (Bryant and Burch.

eld, 1989). Pseudomonas, Arthrobacter, and other aerobic bacteria are

especially effective in the degradation of crude oil (Bushnell and Haas,

1941; Bryant, 1990). However, this degradation is confined to lighter

portions of petroleum—especially paraffins—and bacterial treatment is

beneficial for removal of paraffins from the wellbore, which can restrict the

flow seriously (Pelger, 1992).

(b) Gas Production: The bacterially produced gases (such as CO2, N2, H2,

and CH4) improve the oil recovery in 2 ways:

Dissolves in the crude oil and thus reduces its viscosity

Increases the pressure in the reservoir (Donaldson and Clark, 1982).

The source of this produced gas is in-situ fermentation of carbon sources

such as glucose by usually anaerobic bacteria (Jack, 1983). The most

important gas-producing bacteria are Clostridium, Desulfovibrio,

Pseudomonas, and certain methanogenes (Bryant and Burch. eld, 1989).

(c) Production of Chemicals: Chemicals that can be useful in the

improvement of oil recovery such as organic acids, alcohols, solvents,

surfactants, and polymers are produced by a wide array of microorganisms

(Bryant and Lockhart, 2001).

(d) Selective Plugging: Apart from these techniques, bacteria can be used in

selective plugging (permeability modification) operations. In this method,

polymers or bacteria themselves are used to reduce the permeability of

highly permeable zones or of water channels that form in heterogeneous

reservoirs. Thus the unswept formations are invaded by the water and sweep

efficiency increases (Production Operations, 1997). Bacillus, Xanthamonas,

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and Leuconostoc strainsare reported to be effective in such processes

(Yakimov et al., 1997; Jennemanet al., 1994).

(e) Other Techniques: Other uses of bacteria in the petroleum industry

include the control of unwanted bacteria (such as sulfate-reducing bacteria)

in oil fields (Hitzman and Sperl, 1994) and biodegradation of hazardous

wastes caused by petroleum-related activities for the controlling and

removal of environmental pollution (Ronchel et al., 1995).

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CHAPTER SIX

TYPES OF MICROBIAL PROCESSES IN MEOR

MEOR processes continue to be evaluated for the following different

applications:

Microbial Well Stimulation: This process uses microbes that produce

gases in the oil reservoir.

Microbial Enhanced Water flooding: This process requires the

transportation of nutrients over a long distance within the reservoir; is still in

the developmental phase.

Profile Control and Sweep Improvement: This process uses microbes that

produce polymers, biomass, and slimes that selectively plug the more

permeable zones (Mclnerney and Sublette 1997).

CONTRIBUTION OF MICROBIAL PRODUCTS

Microbial enhanced oil recovery – participating micro organisms produce a

variety of products and they are applied in enhanced oil recovery

Product Micro organism Application in oil recovery

Biomass Bacillus licheniformisLeuconostoc mesenteroidesXanthomonas campestris

Selective biomass plugging

Viscosity reduction

Oil degradation, wet ability alteration

Bio surfactants (emulsan,

Arthrobacter paraffineus Bacillus licheniformisClostridium pasteurianum

Emulsification, decrease of interfacial tension, viscosity

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sophorolipids, peptidolipid, rhamnolipid)

Corynebacterium fascinesPseudomonas rubescens

reduction

Biopolymers (alginate, xanthan, dextran, pullulan)

Bacillus polymyxaBrevibacterium viscogenesLeuconostoc mesenteroidesXanthomonas campestris

Injectivity profile modification, mobility control

Solvents (n-butanol, acetone, ethanol)

Clostridium acetobutylicum

Clostridium pasteurianum

Zymomonas mobilis

Oil dissolution, viscosity reduction

Acids (acetate, butyrate)

Clostridium spp.

Enterobacter aerogenes

Permeability increase, emulsification

Gases (CO2, CH4, H2) Clostridium acetobutylicum Increased pressure, oil swelling, decrease of interfacial tension,

SOURCE: Jonathan et.al, 2003.

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CHAPTER SEVEN

THE TITAN PROCESS OF MEOR

The Titan Process is a Totally Different Form of Microbial Enhanced Oil

Recovery (MEOR) method.

Other MEOR technologies past and present are very different from the Titan

Process. These technologies almost all either inject microbes into existing

oil fields or inject a glucose food source (eg. molasses) to feed resident

microbes. The goal is to have the microbes excrete a by-product referred to

as a biometabolite. These microbial produced by-products are gas,

polymers, acids and surfactants.

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Inherent in the disadvantages of some of the other known MEOR

technologies is that in order to produce 100 pounds of bio-products in a

reservoir, one would have to inject 100-200 pounds of food. There will be a

constant need to feed the microbes many times, usually on a weekly basis.

The Titan Process, by contrast, changes the microbes’ “activity,” and the

feeding process is much less frequent, usually once every three to six

months.

The Titan Process is radically different and only uses resident microbes and

injects a non-glucose nutrient formula which induces the microbes to

become “active” in the reservoir by changing the characteristics of their

skin. The microbes then seek and surround oil droplets in the sandstones and

carbonate strata. This activity dislodges and breaks up oil droplets, which

significantly increases oil recovery.

AVOIDING COMPLEXITIES

Other MEOR processes injecting non-indigenous microbes into a reservoir

will have disadvantages. All species from the plant and animal kingdoms

have very specific habitats and living patterns and naturally over thousands

and millions of years have adapted to their environment. For example, to

adapt penguins to swim in warm tropical waters would require complex and

unnatural biological, chemical or physical adaptations to be implemented.

Microbes are no different.

All oil reservoirs have varying characteristics that make non-indigenous

microbes either die or not function efficiently if introduced. Some of these

32


characteristics are temperature, salinity (salt concentrations), pressure and

pH level. The Titan Process only uses indigenous microbes, avoiding all

complexities of adaptation. Therefore a majority of oil reservoirs are eligible

for the Titan Process. The important prerequisite is that there are microbes

in the reservoir and this scientifically always has been the case.

Titan avoids the engineering of newly injected microbes that require

extensive biotechnical hurdles to be overcome, all of which must take place

for success. For example: 1) making sure the microbes can survive; 2)

making sure they can reproduce sufficiently; and 3) making sure they can

excrete the desired biometabolites efficiently in the new environment.

NO OXYGEN REQUIRED

The Titan Process works on either aerobic or anaerobic microbes (those not

requiring oxygen to survive). The Titan Process induces the microbes to

become oleophilic (to seek and attach themselves to oil droplets) and

induces the microbes to perform an activity and “do” something within the

oil reservoir as opposed to “excreting” something (bio-gas, bio-surfactant or

bio-polymers). This oleophilic (oil-loving) activity is an entirely new

direction in the field of MEOR. This process is simple, efficient,

inexpensive and 100% environmentally friendly.

Because the Titan Process does not inject new microbes into oil fields and

only uses resident microbes, problems and complex solutions dealing with

reservoir pressure, saline content and temperature are not encountered, since

the microbes have already adapted to their environment. Also the Titan

Process does not require an extensive feeding and excretion cycle. It relies

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on the microbes' skin characteristic changes to induce superior oil recovery

activity.

The Titan Process boosts and enhances water flood performance

1. Original Oil Field: Primary production is caused by internal reservoir pressures that have built up over millions of years. This pressure forces a flow of liquids towards the well bore which acts like a release valve. Years of oil production takes place and approximately 20% of the original oil in place is recovered.

2. Oil Field After Several Years: The pressure of the reservoir abates and recovery now has to be aided by forcing water under very high pressure into the reservoir that will push oil towards the production well. This is called a “water flood” and is the most common secondary oil recovery method. The water, pushing through the porous carbonate or sandstone, recovers another 10-15% of the original oil in place.

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3. Before Drilling: Microscopic view of oil and sand compacted under pressure in the oil reservoir.

4. After Primary Production: A great deal of oil still remains in the reservoir but is increasingly difficult to recover.

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CHAPTER EIGHT

ADVANTAGES AND DISADVANTAGES OF MEOR

ADVANTAGES OF MEOR

MEOR has two distinct advantages: microbes do not consume large

amounts of energy and the use of microbes is not dependent on the price of

crude oil, as compared with other EOR processes. Another means of using

microbes in the oil industry involves the use of bacteria to prevent sulfide

production. Sulfides can plug wells thus reducing oil production; they can

also generate hydrogen sulfide, a deadly gas. Microbial enzymes have also

been used in upgrading oil.

Advantages of MEOR

The injected bacteria and nutrient are inexpensive and easy to obtain

and handle in the field.

Economically attractive for marginally producing oil fields; a suitable

alternative before the abandonment of marginal wells.

According to a statistical evaluation (1995 in U.S.), 81% of all MEOR

projects demonstrated a positive incremental increase in oil

production and no decrease in oil production as a result of MEOR

processes.

The implementation of the process needs only minor modifications of

the existing field facilities.

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The costs of the injected fluids are not dependent on oil prices

MEOR processes are particularly suited for carbonate oil reservoirs

where some EOR technologies cannot be applied with good

efficiency

The effects of bacterial activity within the reservoir are magnified by

their growth whole, while in EOR technologies the effects of the

additives tend to decrease with time and distance.

MEOR products are all biodegradable and will not be accumulated in

the environment, so environmentally friendly.

b. Disadvantages of MEOR

Safety, Health, and Environment (SHE).

A better understanding of the mechanisms of MEOR.

The abilibity of bacteria to plug reservoirs.

Numerical simulations should be developed to guide the application

of MEOR in fields.

Lack of talents.

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CHAPTER NINE

CHALLENGES

Nigeria as an oil producing nation has paid no attention to this mode of oil

recovery. The reason is that the players in the field believe that efforts on the

conventional excavation methods have not been fully exploited to give room

for any other processing method for now.

ENVIROMENTAL FACTORS

There are some environmental factors that affect the performance of MEOR

operations. These are temperature, permeability, pH, salinity of the medium,

and oxygen content (Donaldson and Clark, 1982). As all oil reservoirs are

essentially devoid of oxygen, anaerobic bacteria are generally preferred in

field applications.

GROUNDS OF FAILURE

Lack of holistic approach allowing for a critical evaluation of

economics, applicability and performance of MEOR is missing.

No published study includes reservoir characteristics; biochemical

and physiological characteristics of microbiota; controlling

mechanisms and process economics.

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http://en.wikipedia.org/wiki/Holistic_health


The ecophysiology of microbial communities thriving in oil reservoirs

is largely unexplored. Consequently, there is a poor critical evaluation

of the physical and biochemical mechanisms controlling microbial

response to the hydrocarbon substrates and their mobility.

Absence of quantitative understanding of microbial activity and poor

understanding of the synergistic interactions between living and none

living elements. Experiments based on pure cultures or enrichments

are questionable because microbial communities interact

synergistically with minerals, extracellular polymeric substances and

other physicochemical and biological factors in the environment.

Lack of cooperation between microbiologists, reservoir engineers,

geologists, economists and owner operators, incomplete pertinent

reservoir data, in published sources: lithology, depth, net thickness,

porosity, permeability, temperature, pressure, reserves, reservoir fluid

properties (oil gravity, water salinity, oil viscosity, bubble point

pressure, and oil-formation-volume factor), specific EOR data

(number of production and injection wells, incremental recovery

potential as mentioned by the operator, injection rate, calculated daily

and total enhanced production), calculated incremental recovery

potential over the reported time.

Limited understanding of MEOR process economics and improper

assessment of technical, logistical, cost, and oil recovery potential.

Unknowns life cycle assessments. Unknown environmental impact

Lack of demonstrable quantitative relationships between microbial

performance, reservoir characteristics and operating conditions

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http://en.wikipedia.org/wiki/Biological_life_cycle

http://en.wikipedia.org/wiki/Bubble_point


Inconsistency in in situ performance; low ultimate oil recovery factor;

uncertainty about meeting engineering design criteria by microbial

process; and a general apprehension about process involving live

bacteria.

Lack of rigorous controlled experiments, which are far from

mimicking oil reservoir conditions that may have an effect over gene

expression and protein formation.

Kinetic characterization of bacteria of interest is unknown. Monod

equation has been broadly misused.

Lack of structured mathematical models to better describe MEOR.

Lack of understanding of microbial oil recovery mechanism and

deficient mathematical models to predict microbial behaviour in

different reservoirs.

Surfactants: biodegradable, effectiveness affected by temperature, pH

and salt concentration; adsorption on to rock surfaces.

Unfeasible economic solutions such as the utilization of enzymes and

cultured microorganism.

Difficult isolation or engineering of good candidate strains able to

survive the extreme environment of oil reservoirs (up to 85 °C, up to

17.23 MPa).

Clostridium acetobutylicum causes a reduction in oil viscosity due to its

vigorous CO2 production. This gas also causes extensive pressurization.

Clostridium acetobutylicum is also effective in recovering oil from depleted

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reservoirs. The oil recovery increase due to microbial activity is more than

twofold compared to other methods of enhanced oil recovery

Other challenges are :

1. Manipulation of the environmental conditions to promote growth and

product formation by participating micro organisms.

2. Reservoir heterogeneity; a situation where there is variation in

reservoir conditions. That is; when conditions vary from one

reservoir to another (Jonathan et. al 2003).

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CHAPTER TEN

CONCLUSION

Microbial consortia activity within an oil and gas reservoir is a potentially

powerful biological system that can profoundly affect the entire reservoir.

Certain species of microorganisms can be manipulated and controlled to

release trapped oil in significant and economic quantities. Some microbial

methods aid inn paraffin removal while others are designed to modify heavy

oil. Still other micro-organisms produce chemicals, such as surfactants,

polymers, or solvents that are useful in oil recovery processes, either in

above ground facilities or in situ. Most of the methods are designed to treat

single wells and not the entire fields. Several factors make microorganisms

attractive for improved oil recovery. They are self-replicating and relatively

inexpensive to produce. The nutrients required to sustain their growth are

economically priced. Microorganisms produce many of the chemicals, such

as gases, surfactants, acids, solvents and polymers involved in improving oil

recovery. The general criteria for microbes to exist in the reservoir

environment are:

1. Salinity should be less than 15% NaCl.

2. Temperature less than 1800F.

3. Depth less than 8000 ft.

4. Trace elements (As, Se, Ni, Hg) less than 10-15 ppm

5. Permeability greater than 50 md.

6. Oil gravity greater than 150 API.

7. Residual oil saturation greater than 25%.

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Primary recovery usually only accesses 30 to 35 per cent of the original oil

in place (OOIP).

Secondary and tertiary recovery methods may net a further 15 to 25 per

cent OOIP, leaving 30 to 55 per cent OOIP left behind as irrecoverable or

irreducible oil in the reservoir.

MEOR technology targets this remaining oil and aims to enable production

of 80 to 85 per cent of OOIP.

While it is clear that biocatalysis performed by microbes may promote

beneficial chemical reactions such as the production of biosurfactants in a

very specific and energy-efficient manner, a sound understanding of the

underlying principles is important to predict site-specific effects of

microbial activity on fluid flow in porous media and hence on the efficiency

of oil production. Microbial Enhanced Oil Recovery (MEOR) has several

unique advantages that make it an economically attractive method to

enhance oil recovery. MEOR processes do not consume large amounts of

energy as do thermal processes and MEOR processes do not depend on the

price of crude oil as do many chemical recovery processes. Because

microbial growth occurs at exponential rates, it should be possible to

produce large amounts of useful products quickly from inexpensive and

renewable resource. Continued industrialization and economic growth will

increase the demand for oil. The demand for crude oil often exceeds existing

production in many countries. Conventional oil production technologies are

able to recover only about one-third of the oil in the reservoir. Microbially

enhanced oil recovery may offer an economic alternate oil recovery method.

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The principle behind this kind of technology (Microbial Enhanced Oil

Recovery Technology) is the use of non pathogenic bacteria to prevent the

outbreak of infection. But the question remains: what then is the function of

a solid filter in the production well during production? The solid filter are

suppose to trap the bacteria in the oil when flowing through the production

well; thus, if pathogenic or non pathogenic bacteria are used or not ;there

will be no outbreak of infection (Mclnerney and Sublette 1997).

MEOR has two distinct advantages and disadvantages:

Advantages

(1) Microbes do not consume large amounts of energy.

(2) The use of microbes is not dependent on the price of crude oil, as

compared to many of the other EOR processes (Cano Petroleum).

Disadvantages

(1) The microbial enhanced oil recovery process may modify the

immediate reservoir environment by damaging the production

hardware or the formation itself. Certain sulphate reducers can

produce hydrogen sulphide, which can corrode pipeline and other

components of the recovery equipment.

(2) Microbial enhanced oil recovery systems currently represent high-

risk processes to oil producers looking for efficient and predictable

oil recovery (Jonathan et. al, 2003).

Finally, microbial enhanced oil recovery technology may be attractive to

independent oil producers, who mostly operate “stripper wells”

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(producing an average of 0.2 to 0.4 ton of oil per day). A single well

stimulation treatment might increase the rate of production from 0.2 to

0.4 of oil per day and sustain the increased rate for 2 to 6 months without

additional treatments (Jonathan et. al, 2003).

Another attraction in the microbial treatment is clearing up of oil spillage in

the riverine areas and creeks. Recently, a sizeable proportion of the spillage

in the oil slicks that once spread across thousands of miles of the Gulf of

Mexico disappeared completely. This was reported by Yahoo News

Exclusive on Wednesday, the 28th of July, 2010. Perhaps the most important

cause of the oil’s disappearance, some researchers suspect, is that the oil has

been devoured by microbes. The lesson from past spills is that the lion’s

share of the cleanup work is done by nature in the form of oil-eating bacteria

and fungi. The microbes break down the hydrocarbons in oil to use as fuel to

grow and reproduce. A bit of oil in the water is like a feeding frenzy,

causing microbial populations to grow exponentially. This experience is

informing.

Microbes can therefore be cultured to clear spillage even in difficult terrains.

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CHAPTER ELEVEN

REFERENCES

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Industrial Engineering Chemical News, November 10,1926.

Cano Petroleum , http://www.canopetroleum.inc.org/html

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Distribution of the Effect of Nutrient Injection into the deposit in Kuznetsov, USSR, 1958, 6:10-16. New York, USA.

Fourth International Microbial Enhanced Oil Recovery (MEOR) Workshop in Poland, 1961: An Overview of Microbial Enhanced Oil Recovery. Department of Applied Science, Brookhaven Lab, New York 11973, USA.

Jonathan D., Van Hamme, Ajay S. (2003), Microbial Enhanced Oil Recovery,Microbial Molecular Biology Review. Pp. 535-549. American

Society for Microbiology, Canada.

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Mississippi State University, “Microbial Enhanced Oil Recovery”http://www.msstate.edu/depr/wrri/meor

Petroleum Technology Transfer Council , “Microbial Enhanced Oil Recovery” http://www.pttc.org/index.html

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http://www.msstate.edu/depr/wrri/meor

http://www.canopetroleum.inc.org/html


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PROFILE

Attended Benson Idahosa University, Nigeria where I obtained an honours

degree in Microbiology, BSc.(2007). Was employed briefly between 2007

and 2008 as a teacher in School of Mid-wifery, Maiduguri, Borno State of

Nigeria, during my national youth corps service year, where I taught

Microbiology to midwifery students. Worked in 2008 with the World Health

Organisation as an Independent monitor. Worked with Innercity Resource

Centre, Maiduguri, between 2008 to 2010, as a Chapter Representative,

where I offered varying degrees of public health services. Currently doing a

Master Degree Course in University of Benin, Benin City, Nigeria. Desires

sponsorship for research works that will remarkably touch on oil

productivity and oil related paradigm. Contact: [email protected].

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Microbial Enhanced Oil Recovery Process

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