Sunil.G.M Subhanalla.N.S

Introduction EOR MEOR History Mechanism Stimulation of oil production Wellbore cleaning Selective plugging Biosurfactants Microbial products Advantages Disadvantages Environment issues Current status Future prospects Conclusion References

Primary recovery-20% to 30%oil in well recovered without the need to introduce the other substances into the well.Secondary recovery-The oil well flooded with water or other substances to drive out additional 30% to 40% more oil from well.

Known as MICROBIAL ENHANCED OIL RECOVERY ,it involves use of microorganisms to additional recover up to 30% more oil from well.

MEOR involves use of microorganisms to retrieve additional oil from existing well thereby enhancing oil production from oil reservior.Selected microorganisms are introduced into oil wells to produce harmless product such as natural substances or gases which propel the oil out of well.

1936 Beckman proposed the utilisation of microbes for enhanced oil recovery. 1947 Zobell released oil from strata rocks using Desulfovibrio sp. 1954 Kuznetsov inoculated molasses enriched media and observed the gas production. 1958 Heinningen proposed the selective plugging with microbial produced biomass

1977 Yakinov observed the strain of Bacillus licheniformis JF-2 in enhancement of oil recovery. 1983 Bubela examined the effects of reservior env.conditions on microbial culture. 2004 McInemey examined the 200 strains of Bacillus sp.in oil enhancement.

Stimulation of oil production. Wellbore cleaning. Selective plugging Production of Biosurfactants. Microbial Products

Desulfovibrio sp. Bacillus sp. Clostridium sp. Pseudomonas sp. Arthrobacter sp. Microbacterium sp.

Partial repressurisation of reservior by methane and carbon dioxide. Reduction of oil viscosity through dissolution of organic solvents in oil phase. Increase of reservior permeability and widening of fissures and channels through etching of carbaneous rocks.

Cleaning of wellbore region by Increasing the average pore size. Various metabolites Acids react with various minerals,loosen the clay and deposits. Solvents - dissolve the precipitated organic deposits. Biogas push oil from dead spaces and dislodge debris.

Selective plugging of highly permeable zones by injecting slime forming microorganisms,increases the sweeping efficiency and oil recovery.

Biosurfactants are microbially derived surface active agents that can lower the surface tension of oil and act as slippery detergents helping the oil move more freely away from rocks and more easily out of well.

Arthrobacter sp.Bacillus licheniformis Bacillus subtilis Candida lipolytica Corneybacterium lepus Nocardia sp. Pseudomonas sp. Rhodococcus sp.H13-A Torulopsis bombicola Xanthomonas compestris

Trehalose,sucrose, lipids,fructose Lipopeptides Surfactin Sophorose lipid Fatty acids Neutral lipid Glycolipid Glycolipid Sophorose lipid Xanthan

Biodegradibility Low toxicity Environment friendliness.

Biomass

Selective plugging. Modification of solid surface. Reduction of oil viscosity. Alternation in flow properties.

BIOGAS

Carbon dioxide(80%) Hydrogen(20%)

Increase the pressure Increase oil volume, decrease oil viscosity Change pressure potential in fissures,pores

High energy potential in oil field Give better oil mobilisation

Methane

Increase oil production rate

Acetic acid, propanoic acid, valerianic acid

Decrease pH up to Increase 4.8 permeability of rocks

Dissolve the carbonate rock

Dissolve carbonate partially building up new flow channels

Methane, ethanol, propanol, butanol

Decreases interfacial tension

Forces the imbibition of injected,fermented molasses media into pore canals to give more oil from rock

Biolipid

Alter the rock

Increase wettability break oil/water barriers creating emulsion leading to improved flow rate

Cheap Environmentally acceptable alternative. Ability to grow on low cost nutrients. Small size help them to penetrate deep into oil wells enhancing oil recovery. Do not consume large amount of energy.

Need a standardized framework for evaluating microbial activity. Exogenous microbes require facilities for cultivation. Oxygen deployed in aerobic MEOR act as corrosive agent on non resistant equipments and pipelines. Plugging of reservoirs due to aggregation of cell mass or precipitation of metabolites.

(A)

Subsurface water

(B) Waste water

Migration of organism or metabolites into groundwater.Spent fluids due to additional drilling. Equipment washing. Media and Chemicals used for pH adjustment.

(C)

Atmospheric emissionBacteria in filter solids.

(D) Solid wastes

Hydrogen sulphide production.

TITAN INC.-Changing the skin surface of microbes to induce a unique oleophilic activity which dislodges and breakdown oil droplets and create natural emulsion.New project at Daquing field in CHINA to change the structure of polymers to strengthen their ability to break down the long carbon chains of high density crude oil.

TERI,Delhi and ONGC,Gujarat Development of Thermophilic paraffin degrading strain consortium S 2 for prevention of paraffin deposition inside the oil well tubing.

MEOR is direct application of Biotechnology.Use of Genetic engineering and Recombinant DNA technology to develop the strains of bacteria with oil recovery traits and susceptibility to adverse conditions.Recombinant strain of Bacillus mojavensis JF-2,RrB-2 having high efficiency.

To Develop the strains of Bacteria which are better able to survive harsh conditions in oil well but still retain the ability to carry out the chemistry needed for MEOR.To develop the microorganism that can not only live in high temperature of an oil well but also subsist on inexpensive nutrients,remain chemically active.

To develop the Bacteria that can be grown on inexpensive agricultural waste materials which is abundant in supply and is environmentally friendly.

MEOR reduces or eliminates the need to use the harsh chemicals during oilwell drilling.MEOR will become increasingly economically feasible as genetic engineering develops.Methods for developing and growing MEOR bacteria are improving, lowering the production cost making it more attractive alternative to traditional chemical methods.

Belyaev S.S,Borzenkov I.A,Ibatullin T.N, May 17,2004 Use of microorganisms in Biotechnology for enhancement of oil recovery,Microbiology,vol 73(5):pg 590-598 Jang L.K, Yen T.F. 1990 ,Mechanism of MEOR In MEOR Principle and practice :pg 158-163 Microbial enhanced oil recovery,retrieved May 5,2002 from Environmental Biotechnologies inc.www.e-bt.com/meor.htm www.abc.edu/chyn/lect/lect-11 htm http//findarticals.com/p/articals/mi_m315 9

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