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Tertiary Oil RecoveryTertiary Oil Recovery

Steve Ng Kim HoongSteve Ng Kim Hoong

16 October 200716 October 2007

Outline of This Presentation

• Reasons for supporting tertiary oil recovery

• Primary Oil Recovery

• Secondary Oil Recovery

• Tertiary Oil Recovery - Thermal Processes

- Miscible Processes

- Chemical Processes

- Biological Processes

$86 per barrel of crude oil Primary oil recovery – can only recover 10

percent of a reservoir’s original oil in place Secondary oil recovery – 20 to 40 percent Tertiary oil recovery – 30 to 60 percent Undeveloped domestic oil resources still in the

ground total more than 430 billion barrels.

Why are we doing this??

Primary Oil Recovery• The initial stage of

producing oil from a reservoir

• 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)

• Waterflooding

Thermal Processes

• Viscosity is a measure of a liquid’s ability to flow

• High viscosity of oil makes it difficult to flow

• Reduce the viscosity with high temperature

• Steam Injection - Cyclic steam injection - Steam drive

Cyclic Steam Injection

• High pressure of steam (or steam and hot water) injected into well for days/weeks

• Injection is stopped and the reservoir is “soaked”

• Well is then allowed to backflow to surface

• Condensed steam/ hot water vaporizes to drive oil out

• When production is low, process is repeated

• “Huff and Puff” method

Steam Drive

• “Steam flooding”• Same method as water

flooding• Continuous injection of

steam (or steam and hot water)

• A reservoir is developed with interlocking patterns of injection and production wells

• Series of zones developed as the fluids move from injection wells to production wells

Miscible Processes

• Injected fluid dissolves the oil that it contacts• Variety of fluid: - Alcohol - Carbon dioxide - Petroleum hydrocarbons (propane, propane-butane) - Petroleum gasses (ethane, propane, butane, pentane)• Fluid selectivity depends on the type of reservoir and

crude oil • Expensive fluid (supplementary process to recover fluid

or use it sparingly)• “Slug” – 5% to 50% of reservoir volume pushed through

by gas/water brine or chemically treated brine

CO2 Enhanced Oil Recovery• All the petroleum hydrocarbons are expensive (not viable in economic sense)• CO2 is cheap and widely available (mostly use natural CO2 deposits)• Complete mixing depends on reservoir temperature, pressure, chemical nature and

density of oil• Generally, it’s deeper than 1200m and oil lighter than 220 API• CO2 is stable in supercritical state (6.9 MPa and 310C)• Injected CO2 will diminish the interfacial tension between itself and the crude oil

Chemical Processes

• Involved the usage of surfactant/polymer, polymer, alkaline flooding

• Surfactant/polymer flooding:

- microemulsion/micellar flooding

- detergent-like material injected to modify the oil interactions with its surroundings

- emulsify/partly dissolve oil

- high cost, small volume

• Polymer flooding

- a chemically augmented waterflood

- polyacrylamides/polysaccharides

- increase effectiveness of water in displacing oil• Alkaline flooding

- sodium hydroxide, sodium silicate, sodium carbonate

- react with constituents in the crude oil or rock/crude oil interface

- detergent-like material to reduce the ability of the formation to retain oil

Biological Processes• Utilize microbes to enhance oil recovery• Occupy pore spaces to release trapped oil and reduce water cut• Microbial response: - larger - shrink - oleophilic - attach and surround oil droplets - deform droplets to form smaller droplets - smaller droplets able to escape pore spaces - byproduct of metabolism (CO2 and biomass) - biosurfactants (slimy substances – exopolysaccharides) - Xanthomans campestris bacteria (Xantan)• Reservoir response: - microbes attached to water and oil droplets move faster through high permeable

sections of the field (thief zones). This combination and fast flow creates a natural emulsion only in the thief zones.

- thief zones are temporarily blocked - water is diverted to unswept areas of the field, thus increasing sweeping efficiency

Case Study: Beatrice Field, North Sea, England

• The Beatrice Field is in a steep North Sea production decline

• Scheduled to be abandoned in 1995-96• Applied the microbial enhanced oil

recovery (Titan Process) from 1992-95• Oil production scheduled to decline to

5000 bopd (now producing 12000 bopd)• 5.5 million barrels of excess oil was

produced

REFERENCES

• http://www.titanoilrecovery.com/pdfs/TitanBrochure.pdf• http://www.biobasics.gc.ca/english/View.asp?x=793• http://www.fossil.energy.gov/programs/oilgas/eor/

index.html• Enhanced Oil Recovery Potential in the United States,

Congress of the United States, Office of Technology Assessment, January 1978, #PB-276594

• Enhanced Oil Recovery Scoping Study, A. Amamath, 1999

THANK YOU!!