Injection of Gas and Improved Oil Recovery - the Norwegian Experience

BySteinar Njå,

Norwegian Petroleum Directorate

The first oil production in

Norway was done by Philips

Petroleum Company Norway

using the revamped drilling rig

Gulftide from the summer 1971

until spring 1974, i.e. during

development of the Ekofisk

field.

This is the only time flaring of

associated gas has been

approved in Norway for other

reason than safety. I.e. for

regular production.

Flaring of Associated Gas

Historical view of the flaring on the NCS

Gas export started

CO2 tax introducedNPD Task force

1975

1976

1977

1978

1979

1980

1981

1982

1983

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1985

1986

1987

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1989

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2010

0

5

10

15

20

25

30

35

40

Gas

fla

rin

g (

Sm

3) p

er S

m3

sold

o.e

.

Snøhvit production starts

Gas sale started

NPD task force

CO2 tax introduced

Petr. Act § 4-1“Production of petroleum shall take place in such manner that as much as possible of the petroleum in place in each individual petroleum deposit, or in several deposits in combination, will beproduced.

The production shall take place in accordance with prudenttechnical and sound economic principles and in such a manner that waste of petroleum or reservoir energy is avoided.

The licensee shall carry out continuous evaluation of production strategy and technical solutions and shall take the necessary measures in order to achieve this.”

Petr. Act § 4-4“Flaring in excess of the quantities needed for normal operational safetyshall not be allowed unless approved by the Ministry”

Prudent Extraction and Utilization

GGFR, Paris 25.4.12

Petroleum Act requires licensees to address associated gas utilization (Plan for Development and Operation (PDO) and Plan for Installation and Operation (PIO)

EIA is part of the PDO/PIO approval process

Often PDO/PIOs only approved after significant investments to avoid flaring (eg. temporary re-injection)

Regulatory authority: Norwegian Petroleum Directorate (NPD)

Measurements, reporting and monitoring Metering systems with accuracy of +/- 5%

Audited by NPD and reported volumes basis for taxation

Assessment of policies and regulations Building of gas infrastructure of vital importance

Regulation of grid accessState owns infrastructure through Gassled, non-discriminatory access with Ministry of Petroleum and energy setting transport

tariffs

Tax on flaring is part of a general CO2 tax on energy combustion

Little/no impact on routine flaring but has help improve technologies and operational procedures for non-routine flaring

CO2 tax of importance for continued compliance

Overview of policies and regulations – Norway

Total gas production on the NCS, 2000-2010

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 20100

20

40

60

80

100

120

140

160

Export Injection Fuel and Flaring To NGL and condensate

Mill

. Sm

³ o.e

. per

yea

r

GGFR, Paris 25.4.12

Focused Norwegian R&D Programs on IOR

EORField Pilots !

Financed by oil

companies Authorities

+ oil companies

Experience transferFORUM

Follow up R&D programs

R&D Programs by NRC

To be continued

1981 2010

Financed by group of oil companies

State R&D Program for IOR and Reservoir Technology1985 - 91

GGFR, Paris 25.4.12

Background for decisions on gas injection

Lack of gas export opportunity and flaring not permitted

and /or

Gas injection gave higher oil recovery and higher economic value than water injection

Injected gas to be sold to the market at an later stage

Historical gas injection per field on the Norwegian Continental Shelf

GGFR, Paris 25.4.12

GGFR, Paris 25.4.12

Norwegian experience with gas injection

Successful IOR projects !!!

Lower residual oil with gas injection. Reported to NPD:

Average Sorg = 0,10 (fields with gas injection)

Average Sorw= 0,22 (fields with water injection)

Challenge

The timing of the production of the injected gas

GGFR, Paris 25.4.12

Effect of gas injection

Conclusions from NPD review:

28 % of the gross gas production has been reinjected

Additional 320-360 million scm oil, including approved future plans for gas injection

Total efficiency; additional oil :

0,43-0,48 million scm oil/ billlion scm gas

Historical gas injection and future approved plans for gas injection

GGFR, Paris 25.4.12

The economics of gas re-injection

Gas re-injection has to compete with other alternatives for utilization

For IOR purposes there are always great uncertainties regarding efficiency and added recovery of oil

For storage purposes better utilization of transportation systems and improved delivery efficency is the main economical driver

Some gas will be used as fuel(2-3%) to reinject and 15-25% of gas reinjected will be left in the reservoir

GGFR, Paris 25.4.12

Conclusions (I)

1. The combination of

prohibition against flaring of gas IOR research efforts authorities initiatives prudent technical work and sounds decisions by oil companies

has led to several successful gas injection projects

2. Several large Norwegian fields with gas-injection have recovery factors for oil in the range 53-66 %.

3. Gas injection in Norwegian fields yields an extra oil recovery in the range 320 to 360 million scm.

GGFR, Paris 25.4.12

Conclusions (II)

4. An important question is how long it is profitable to keep the injected gas in the reservoir. The timing of the massive production of the injected gas should not be fixed at an early stage, but needs to be updated late in the field life.

5. Re-injection of gas for IOR purpose represents a great potential for value creation. If the gas cannot be exported to the market or utilized on site, the reinjection is also an alternative that contributes to reducing a global environmental problem

GGFR, Paris 25.4.12

GGFR, Paris 25.4.12

Thank you for your attention!

www.npd.no