Microbial Enhanced Oil Recovery Process

MICROBIAL ENHANCED OIL RECOVERY PROCESS (MEOR)

Detailed Documentation & Appraisal Of:

BY EZEANYA, CHINYERE CHARITY (BSc. Hons)

Miss Ezeanya, Chinyere Charity

(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 it is clear that biocatalysis performed by microbes may promote beneficial 3

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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. 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. 4

Microbial Enhanced Oil Recovery (MEOR)

TABLE OF CONTENT

PAGES

ABSTRACT

1

TABLE OF CONTENT

3

CHAPTER ONE Enhanced Oil Recovery (EOR) Process Modes of EOR Chemical Methods Gas Flooding Thermal Process Computer Simulation Oil Recovery Factor

5 7 7 8 9 10 10

CHAPTER TWO Description And History of MEOR Description History Current Status of MEOR

11 11 12 14

CHAPTER THREE The Science of MEOR Biotechnology and MEOR

15 17

CHAPTER FOUR Classification of MEOR Ventures Working in MEOR Microbial Flooding Recovery

19 19 21

CHAPTER FIVE Mechanisms of Microbial Enhanced Oil Recovery

25

5

Miss Ezeanya, Chinyere Charity CHAPTER SIX Types of MEOR

28

CHAPTER SEVEN The Titan Process of MEOR Avoiding Complexities No Oxygen Required

30 31 32

CHAPTER EIGHT Advantages of MEOR

35

CHAPTER NINE Challenges Environmental factors Grounds of Failure

37 37 37

CHAPTER TEN Conclusion

41

CHAPTER ELEVEN References Profile

44 48

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Microbial Enhanced Oil Recovery (MEOR)

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. 7

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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: 8

Microbial Enhanced Oil Recovery (MEOR)

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 10

Microbial Enhanced Oil Recovery (MEOR)

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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Microbial Enhanced Oil Recovery (MEOR)

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 twothirds 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. 13

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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 14

Microbial Enhanced Oil Recovery (MEOR)

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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Microbial Enhanced Oil Recovery (MEOR)

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. 18

Microbial Enhanced Oil Recovery (MEOR)

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 19

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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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Microbial Enhanced Oil Recovery (MEOR)

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 22

Microbial Enhanced Oil Recovery (MEOR)

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 24

Microbial Enhanced Oil Recovery (MEOR)

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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Microbial Enhanced Oil Recovery (MEOR)

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 aeruginosa,

bacterial strains identified as Pseudomonas

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 27

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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 28

Microbial Enhanced Oil Recovery (MEOR)

efficiency increases (Production Operations, 1997). Bacillus, Xanthamonas, 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 licheniformis Leuconostoc mesenteroides Xanthomonas campestris

Selective biomass plugging

Arthrobacter paraffineus

Emulsification, decrease of interfacial

Bio surfactants (emulsan,

30

Viscosity reduction Oil degradation, wet ability alteration

Microbial Enhanced Oil Recovery (MEOR) sophorolipids, peptidolipid, rhamnolipid)

Biopolymers (alginate, xanthan, dextran, pullulan)

Solvents (nbutanol, acetone, ethanol)

Bacillus licheniformis Clostridium pasteurianum Corynebacterium fascines Pseudomonas rubescens Bacillus polymyxa Brevibacterium viscogenes Leuconostoc mesenteroides Xanthomonas campestris

tension, viscosity reduction

Clostridium acetobutylicum

Oil dissolution, viscosity reduction

Injectivity profile modification, mobility control

Clostridium pasteurianum Zymomonas mobilis

Acids (acetate, butyrate)

Clostridium spp.

Gases (CO2, CH4, H2)

Clostridium acetobutylicum

Enterobacter aerogenes

SOURCE: Jonathan et.al, 2003.

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Permeability increase, emulsification Increased pressure, oil swelling, decrease of interfacial tension,

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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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Microbial Enhanced Oil Recovery (MEOR)

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 33

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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 34

Microbial Enhanced Oil Recovery (MEOR)

on the microbes' skin characteristic changes to induce superior oil recovery activity. The Titan Process boosts and enhances water flood performance

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. 1.

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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Before Drilling: 4. After Primary Production: Microscopic view of oil and A great deal of oil still sand compacted under remains in the reservoir but is pressure in the oil reservoir. increasingly difficult to recover. 3.

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Microbial Enhanced Oil Recovery (MEOR)

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. 37

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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.

38

Microbial Enhanced Oil Recovery (MEOR)

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

mechanisms and process economics. 39

of

microbiota;

controlling

Miss Ezeanya, Chinyere Charity •

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

40

Microbial Enhanced Oil Recovery (MEOR) •

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

41

Miss Ezeanya, Chinyere Charity

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).

42

Microbial Enhanced Oil Recovery (MEOR)

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%. 43

Miss Ezeanya, Chinyere Charity

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. 44

Microbial Enhanced Oil Recovery (MEOR)

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).

45

Miss Ezeanya, Chinyere Charity

Finally, microbial enhanced oil recovery technology may be attractive to independent oil producers, who mostly operate “stripper wells” (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.

46

Microbial Enhanced Oil Recovery (MEOR)

CHAPTER ELEVEN

REFERENCES .

Beckman J. W (1926), The Action of Bacteria on Mineral Oil, pp. 3. Industrial Engineering Chemical News, November 10,1926. Cano Petroleum , http://www.canopetroleum.inc.org/html Department of Energy, Grant and the Venezuelan Ministry of Energy and Mines, Microbial Enhanced Oil Recovery April 1997. (DOE/BC- 97/3/SP OSTI ID:14278), USA. 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. Lazar I. (1987), Research on the Microbiology of Microbial Enhanced Oil Recovery(MEOR) in Romania, Jeannette King and Debra Stevens (publishers), pp124-153; Bartles Ville Project office. Department of Energy, Grant, USA. Mclnerney J. and Sublette B.1997, Petroleum Microbiology: Biofouling, Scouring and Improved Oil Recovery, pp. 600607. ASM Press, Washington D.C, USA. 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 47

Miss Ezeanya, Chinyere Charity

The World Abatement USA.

Bank Group, (1998), Pollution Prevention and Handbook,pp.446, 447-455. Washington D.C.,

ZoBell C.E, (1947), Bacteria Release of Oil from Oil-bearing Materials, Parts 1 and 11. Pp. 36-47(part 1), 35-41(part 11). World Oil 126, USA. Ballangue, J., E. Masion, J. Amine, H. Petitdemange, and R. Gay. 1987. Inhibitor effect of products of metabolism on growth of Clostridium

acetobutylicum.

Applied

Microbiology

and

Biotechnology 26:568. Bryant, R. S. 1990. Screening Criteria for Microbial Eor Processes, Topical Report, Bartlesville Project Of. ce, Department of Energy, Bartlesville, OK. Bryant, R. S., and T. E. Burch. eld. 1989. Review of microbial technology for improving oil recovery. SPE Reservoir Eng. J. 4(2):151. Bryant, S. L., and T. P. Lockhart. 2001. Reservoir engineering analysis microbial enhanced oil recovery. Journal of Petroleum Technology 53(1):57. Bushnell, L. D., and H. F. Haas. 1941. The utilization of certain hydrocarbons by microorganisms. Journal of Bacteriology 41:529. Donaldson, E. C., and J. B. Clark. 1982. Conference focuses on microbial enhancement of oil recovery. Oil and Gas Journal 82:47. Hitzman, D. O. 1983. Petroleum microbiology and its role in enhanced

oil

recovery,

Proc.

of

the

1982

Symposium on MEOR, NTIS, Spring. eld, VA, 162. 48

International

Microbial Enhanced Oil Recovery (MEOR)

Hitzman, D. O., and G. T. Sperl. 1994. A new microbial technology for enhanced oil recovery and sul. de prevention and reduction, Proc. SPE/DOE Ninth Symposium on Improved Oil Recovery, Tulsa, OK, Pap. SPE/DOE 27752, 171. Jack, T. R. 1983. Enhanced oil recovery by microbial action. In T. F. Yen, F. K. Kawahara,R. Hertzberg (eds.), Chemical and Geochemical Aspects of Fossil Energy Extraction, Ann Arbor, MI: Ann Arbor Science. Jenneman, G. E., P. D. Mof. tt, and G. R. Young, 1994. Application of a microbial selective plugging process at the North Burbank unit: Prepilot tests and results, Proc. SPE/DOE Ninth Symposium on Improved Oil Recovery, Tulsa, OK, Pap. SPE/DOE 27827, 493. Lepage, C., F. Fayolle, M. Hermann, and J. P. Vandecasteele. 1987. Changes in membrane lipid composition of Clostridium acetobutylicum during acetone-butanol fermentation: Effects of solvents, growth temperature and pH. Journal of General Microbiology 133:103. Pelger, J. W. 1992. Wellbore stimulation using microorganisms to control and remediate existing paraffin accumulations, Proc. SPE Intl. Symposium on Formation Damage Control, Lafayette, LA, Pap. SPE 23813, 419. Production

Operations

(Editorial).

Alternative

permeability-modi.

1997.

cation

Biotechnology:

methods.Journal

of

Petroleum Technology 49(3):280. Ronchel, M. C., C. Ramos, L. B. Jensen, S. Molin, and J. L. Ramos, 1995.

Construction

and

behavior 49

of

biologically

contained

Miss Ezeanya, Chinyere Charity

bacteria

for

environmental

applications

in

bioremediation.

Applied and Environmental Microbiology 61(8):2990. Yakimov, M. M., M. M. Amro, M. Bock, K. Boseker, H. L. Fredrickson, D. G. Kessel, and K. N. Timmis. 1997. The potential of Bacillus licheniformis strains for in-situ enhanced oil recovery. Journal of Petroleum Science and Engineering 18:147.

PROFILE

Attended

Benson

Idahosa

University,

obtained an honours degree

Nigeria

where

I

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 50

Microbial Enhanced Oil Recovery (MEOR)

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 paradigm. Contact: [email protected].

51

and oil related