Gas reinjection and flaring reduction Norway's experience - Steinar Nja (Norway Petroleum...

Carbon Limit, Amsterdam, 03.12.08

Gas Reinjection

Presentation at

Workshop on”CDM Methodology Issues related to Gas Flaring”

Amsterdam 03.12.08

BySteinar Njå, Project Director,

Norwegian Petroleum Directorate


Content of presentation

Gas reinjection in general Purpose of gas reinjection Gas and Reservoir properties Injection facilities The economics of gas reinjection

The Norwegian Case Legal framework Some field cases

Gas reinjection related to CDM Reinjection schemes Injection Monitoring

Closing remarks

04/12/23 3

Main stages in Production and Capture

Reservoir

Separation

Oil

Gas

Flare

Sale ”Utilization”

Flue gasCO2 Capture

CO2 Storage

Clean flue gas

Gas Reinjection

Products:- Electricity- Chemicals- LNG- Others

Fuel

CO2 Reinjection ?

Well stream


Purpose of gas reinjection

High pressure gas reinjection is used for many producing fields: Provides pressure maintenance Improves recovery of oil Provides storage and swing capacity

Different form for application: Non-miscible injection Miscible injection Tertier injection after water flooding Injection in gas/condensate fields


Gas Properties and Reservoir Considerations

For Improved Recovery Reservoir geology and configuration Compatability with reservoir fluid Miscibility Injectivity Theft Zones(High permeability layers, Hetrogeniety)

For Storage Reservoir geology and configuration Available volume Injectivity Reservoir pressure

Leakage Normally not a problem Strict rules for well plugging before abandonment


Injection facilities

Standard high pressure compressors are applied driven by gas turbines or electrical motors

Gas have to be cleaned and conditioned before compressed and reinjected into the reservoir

Injection wells normally cheaper than production wells


The economics of gas reinjection

Gas reinjection 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.


Reservoir Management

System for Management and Monitoring is requiered.

Most companies have established monitoring program for each field based on geological models, petrophysical properties of the reservoir and reservoir simulations.

Reservoir behaviour evaluated on regular basis by flow measurement and well testing.

In some instances tracers are used to understand flow regimes in the reservoir


The Norwegian Case


The Norwegian Continental Shelf


Petroleum production

2012

0

50

100

150

200

250

300

1971 1980 1989 1998 2007

mill

ion

er

Sm

3 o.e

.

mill

ion

Sm

3 o.e

.

Gass/Gas

Kondensat/Condensate

NGL

Olje/Oil


Gas Balance - Norwegian Continental Shelf

0

30

60

90

120

150

180

210

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

2011

Bil

lio

n S

m3

Fuel&Flare

Gas injection

Resourcesr

Reserves

Historic export


Petroleum 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 be produced.

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.”

Prudent Extraction


Gas flaring and venting regulations Petroleum Act: § 4-4

“Flaring in excess of the quantities needed for normal operational safety shall not be allowed unless approved by the Ministry”:

Associated gas utilisation required to get authority approval of Plan for Development and Operation

Annual gas flaring permits

Avoid waste of petroleum and reservoir energy

Cold venting is not in accordance with the principle of environmentally prudent petroleum production

CO2-tax charged on all fuel and flare consumed and vented gas (~USD 0.1 per Sm3 gas)


Reservoir Management

Production reg. - Section 27

“The licensee shall continually monitor the deposit during production, including pressure and flow conditions, produced or injected volumes per well, zone and reservoir, the composition of components of petroleum etc.

The total monthly production and injection volumes of the field shall be apportioned to each individual well on a monthly basis according to recognized norm.”


Gas (and WAG) injection on NSC – a success !

EOR effect to date estimated to be 180-220 million Sm3 extra oil and condensate

1984: gas into Ekofisk and Statfjord


Gas injection cases

Togi

Statfjord

Grane

Oseberg

Troll

Water injector

Gas injector

Producer

BrentTarbert/NessEtive/Rannoch

StatfjordNansen/Eiriksson

Raude

Cook

US WI/GI

WAG-injector

LS WAGLB WAG

B EF C block UB WAG

WAG injection in Brent and Lower Statfjord Updip water injection and gas injection in Upper Statfjord High drilling and well activity level


Area consideration (Tampen)

Fields evaluated for external injection:

Snorre Sygna Statfjord Nord Vigdis

Possible source for gas: Gullfaks

CO2-injection

Associated CO2- removed from produced gas and injected into storage reservoar Snøhvit Sleipner

CO2 from gas power plant Test Centre Mongstad

NPD is currently working on a project to identify the best storage reservoar for a planned full-scale gas power plant in Norway

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CO2 injection and storage at Sleipner

Sleipner A

Sleipner T

Utsira Formation

Heimdal Formation

Production and Injection wells

CO 2

CO2 Injection well 1000m

2000m

2500m

0

500m

1500m

1000m0 500m 1500m


Gas reinjection related to CDM

Reinjection schemes

Reinjection for IOR Reinjection for storage



Reinjection will reduce CO2 emission

Reinjection for improved oil recovery(IOR) Major reduction in CO2 emission until injected gas is reproduced

and utilized Some emission due to power generation for injection compressors

Reinjection for storage Reduction in CO2 emission for as long as the gas is being stored

assuming no leakage Necessary precautions to avoid leakage has to be made as well as

establishment of system for leakage monitoring.


Injection Monitoring

Program for Reservoir Management Petroleum producing countries have rules and regulations for proper

depletion and requirments for reservoir management In general most companies will have program established for

reservoir monitoring Behaviour of gas injected can be traced using well testing and

reservoir simulations Gas resirculation will be discovered through GOR measurement Possible to establish monitoring program that controls reproduction

of injected gas.

Additionality

IOR from gas injection has in the long run proved more economical than expected

Yet, in a project perspective the IOR-effect may be too risky for investment purposes

CDM may be a good solution for projects to reduce flaring on fields in production.

Flaring restriction should however be handled at planning stage as a requirement to the company developing the field.



Closing remarks

Gas reinjection is a well known method for storing of gas instead of flaring

Gas reinjection will in most cases improve oil recovery if applied in a right way

Calculation and accounting of gas injected and stored should be possible through proper reservoir monitoring

Considering the huge amount of gas currently being flared, gas reinjection is a fast and valuable alternative to avoid flaring and thereby reduce CO2 emission

Ekofisk – Future CO2 Storage?


The World


The difference between natural gas(CH4+) and CO2

CH4+

Rich in energy Easy to produce Easy to store High value on storage

CO2

Low in energy Difficult to extract Easy to store Low value on storage

Gas reinjection and flaring reduction Norway's experience - Steinar Nja (Norway Petroleum...

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