Post on 24-Feb-2016
description
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
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
0
5
10
15
20
25
30
35
40
Gas
flar
ing
(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 access
State 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 combustionLittle/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