The Three Stages of Oil Field Development

Enhanced Oil Recovery occurs after all possible oil is pumped

out of the ground using traditional methods. Primary and

secondary steps in the extraction of oil include the traditional

methods while the tertiary step includes oil recovery in new,

enhanced methods such as CO2 injection.

Primary Recovery

Primary recovery produces oil and gas using the natural pressure of the reservoir

as the driving force to push the material to the surface. Wells are often

‘stimulated’ through the injection of fluids, which fracture the hydrocarbon-

bearing formation to improve the flow of oil and gas from the reservoir to

the wellhead.

Secondary Recovery

Secondary recovery uses other mechanisms – such as gas re-injection and

water flooding – to produce residual oil and gas remaining after the primary

recovery phase.

Tertiary Recovery

Tertiary recovery involves injecting other gases (such as carbon dioxide), or

heat (steam or hot water) to stimulate oil and gas flow to produce remaining

fluids that were not extracted during primary or secondary recovery phases.

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V E RT I C A L C O 2 F L O O D

EOR: Enhanced Oil Recovery

CO SOURCE2 O IL TO MARKE T PRODUCT ION WELL

COR ECYCLED

2

O ILBANK

COIN J E CTE D

2

GAS OIL CONTACT

WATER OIL CONTACT

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By applying this new technology to the field,

oil wells that may, under previous circumstances,

have reached the end of their lives, can now operate

for many more years, producing much more oil.

H O R I Z O N TA L C O 2 F L O O DTertiary Recovery: The CO2 process:

1 CO2 is injected into the reservoir via injection wells.

2 The CO2 reduces the viscosity of the trapped oil so it flows more easily.

3 Water can be injected in alternating cycles with CO2 to sweep the oil to

the producing wells.

4 Production wells pump the oil, along with CO2, produced water and any

associated natural gas to the surface.

5 The CO2 and associated natural gas are separated at the production

satellite facility. Natural gas liquids are extracted and sold and the CO2

is recycled for reinjection.

6 The oil and produced water are separated at the central tank battery.

The oil is piped to holding tanks where it is metered and sold.

7 The produced water is transported to the central water injection station

and is pressurized for reinjection.

Waterflood Wedge Primary Wedge

EOR Phase Group #3 EOR Phase Group #2

EOR Phase Group #1

Oil

Rat

e, b

bl/

d

Time

CO2CO2

CO2CO2

WATER

MISC IBLEZONE

OILBANK

DRIVEWATER

ADDIT IONALOIL

RECOVERY

CO SOURCE2 O IL TO MARK ET PRODUCT ION WELL

ALTERNAT ING COAND WATER INJECT ION

2 CO AND WATE RRECYCLED2