USE OF MICROBES IN MINERAL BENEFICIATION AND OIL RECOVERY

presented byEssam Yahya

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Currently global energy production from fossil fuels is about 80-90% with oil and gas representing about 60 %

During oil production, primary oil recovery can account for between 30-40 % oil productions

While additional 15-25% can be recovered by secondary methods such as water injection leaving behind about 35-55 % of oil as residual oil in the reservoirs

This residual oil is usually the target of many enhanced oil recovery technologies and it amounts to about 2-4 trillion barrels.

Introduction

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Enhanced oil recovery (EOR) methods

Enhanced oil recovery (EOR) methods aimed to recover additional oil after primary recovery or natural drives in the reservoirs

Water flooding (water injection).

Gas injection (not miscible).

Carbon dioxide flooding (miscible).

Steam injection and in-situ burning.

Surfacants or foams injection.

Microbial Enhanced Oil Recovery Methods.

Primary Oil Recovery The initial stage of producing oil from a reservoir.

Primary recovery: natural mechanisms (5-10%).

Natural gas expansion

Use natural forces such as:- - expansion of oil, gas or both - displacement by naturally pressurized water - drainage from a reservoir in high elevation to a well

in lower elevation - artificial techniques (pumps)

Secondary Oil Recovery Injection of fluids in a series of wells to

force oil into another series of wells.

Essentially augmenting the natural forces used in primary methods.

Water flooding.

Secondary recovery: fluïd injection (25-30%)

Water or natural gas circa 65% not recovered

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Tertiary or enhanced oil recovery

Tertiary or enhanced oil recovery (EOR): oGas injection.o Thermal recovery (TEOR).oChemical injection

• Alkaline, surfactant, polymer and MICRO-ORGANISMS.• MEOR Extra 20-30% recovery!

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What is microbial enhanced oil recovery (MEOR)?

Use of microbes to improve oil recovery, established by Beckman 1926.

How much additional oil can be produced? Up to 60% oil in place after primary recovery.

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Schematic of MEOR Technology

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

Modification of reservoir rock Improvement of porosity and permeability Reaction with calcareous rocks and CO2 production Selective or non selective plugging Emulsification through adherence to hydrocarbons Modification of solid surfaces Degradation and alteration of oil Reduction of viscosity and oil pour point Desulfurization of oil Reservoir repressurization Oil swelling Viscosity reduction Increase permeability due to solubilization of carbonate rocks by CO2 Dissolving of oil Lowering of interfacial tension Emulsification Mobility control Selective and non-selective plugging

MEOR Application During last 15 years some countries began to develop and apply

MEOR methods successfully again such as USA, Russia, Romania, Germany, Malaysia, China, India, Norway, UK, Venezuela, Iran, Trinidad among others.

More than 300 cases of MEOR methods application – mostly of single well stimulation – were reported.

MEOR Application

1. Selective Plugging 2. Hydrocarbon Chain Degrading Bacteria3. Cyclic Microbial Recovery

1. Selective Plugging Recovery:

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

Totally during 1996-2002, 68 injectors were treated.

1 t of bio-product gave up to 756 t of oil.

Microbes plug the washed out tunnel forcing

water to flow through yet unwashed areas.

2. Microbiological Stimulation for Oil Recovery

Stimulating naturally occurring bacteria that feed on oil to create conditions that release residual oil from the reservoir.

The interfacial tension between water and oil is lowered resulting in easier oil recovery.

Stat oil • Applying an aerobic MEOR technique to the

development of Norne field. • Considers that the technique will produce about

32 million incremental barrels; about 6% above what would otherwise have been recovered.

Carbon hungry bacteria are injected by Statoilinto the Norne field to free oil clinging to the

reservoir rock and enhanced recovery

3. Hydrocarbon Chain Degrading Bacteria

Viscous Oil (Bokor Field

Malaysia)

Before Treatment

After Treatment Over past 5 months (post MEOR)

Production rate 152 b/d 334 b/dWater cut 75 % 45 %

Heavy oil field in Western

Siberia, Russia, January, 2006

Before Treatmen

t

After Treatment For a Period 3 Months

Production rate

5 - 7 m3/h

15 -19 m3/h (mostly 16-17 m3/h)

Water cut 48 % 25 %Quality of oil - improved

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

The microbes degrade hydrocarbons to the following components.

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Microbes replicate -process is self sustaining.

Eliminates logistical hassle.

Find their own carbon source in the reservoir.

Create recovery enhancing chemicals where needed.

A Rather cheap method compared to CO2 injection.

The Best Part of MEOR

Self-propagating

Self- directing

Q1 What are the most common Enhanced oil recovery (EOR) methods ?

Q2 explain the main differences between primary and secondary oil recovery, and why we need to go for the tertiary oil recovery?