Rick Wilkinson
OGJ correspondent
MELBOURNE, Sept. 27 -- The latest ministerial statement from the Carbon Sequestration Leadership Forum (CSLF) held in Melbourne has approved 10 collaborative carbon capture and storage projects around the world.
The projects—four of which directly involve oil and natural gas or coalbed methane fields and reservoirs—are designed to increase knowledge in aspects of geosequestration, including technology, economics, health, safety, and environmental issues.
These are designated pilot projects and are in addition to several existing and proposed commercial petroleum operations worldwide that have a carbon dioxide sequestration component.
Prominent projects
Of the pilot projects, the two most advanced are the Weyburn enhanced oil recovery (EOR) project in Saskatchewan, Canada, and the Sleipner offshore gas field development in the Norwegian North Sea.
The US, Canada, and Japan are working together in the Weyburn II CO2 storage project. Phase 1 conducted trials of CO2 injection into the oil reservoir.
Phase II will magnify the scale with the transport of 95 MMcfd of 95% pure CO2 to the field via a 320-km pipeline from North Dakota. The CO2 will be injected into the field for EOR.
This new phase will closely monitor the CO2 migration within the reservoir to determine its performance as an EOR tool and to assess any risks involved in its long-term use and intake into the reservoir. The project will run for about 4 years.
At Sleipner natural gas field, CO2 content is about 10%. The CO2 has been extracted from the natural gas flow since 1996 at the rate of 1 million tonnes/year and reinjected into a nonpetroleum reservoir at 1,200 m overlying the field reservoir, which is at 3,000 m subsea.
Norway and the European Commission are collaborating in Phase II of this project; each will continue to monitor the field to track the CO2 migration with seismic surveys. There also will be studies to obtain information about geochemistry and dissolution processes.
Additional work includes feasibility studies on other geologic settings in the region. The aim is to gather data to develop sound methodologies for assessment, planning, and long-term monitoring of underground CO2 storage on and offshore.
Other projects
Other pilot projects include work by the EC and Germany to evaluate carbon geosequestration in an existing natural gas storage facility near Berlin and in a deeper land-based underground saline aquifer nearby. Similar work is being undertaken by the US and Australia in a pilot project near Houston injecting CO2 into the Frio formation.
Another approved pilot project in Canada—this time in Alberta and involving teams from Canada, the US, and the UK—will look at the potential for injection of CO2 into deep, unmineable coal seams. The aim is to assess the potential and economics for liberation of coal seam methane (where the CO2 displaces methane from the coal) and permanent storage of the CO2 injected. This project could extend to 2010.
Apart from Sleipner, several other CO2 reinjection projects are being considered on a commercial scale as part of proposed natural gas field development projects. These are outside the pilot schemes approved by CSLF.
Statoil ASA's new Snøhvit gas field in the Norwegian Barents Sea has a high CO2 content. The proposed development includes piping the field gas to an onshore facility. CO2 will be extracted from the gas stream and piped back offshore for injection into a sand aquifer underneath the gas field (differing from Sleipner where the CO2 storage lies above the gas reservoir). The methane will then be converted to LNG at the onshore facilities. Snøhvit is expected on stream in 2006.
Statoil is involved in another field development that includes carbon geosequestration, this one in Algeria's In Salah field operated by BP PLC. The reinjection of CO2 will have the double bonus of sequestering CO2 and providing pressure maintenance.
A third project proposal is Gorgan gas field off Western Australia, operated by ChevronTexaco Corp. With CO2 content in the fields of this project above 12%, the plan is to pipe gas to LNG production facilities on Barrow Island and reinject the CO2 into a deep aquifer. The current timetable is for Gorgon to come on stream in 2009.
Several other large, undeveloped gas fields off northwest and northern Australia (Scott Reef and Brecknock and Evans Shoal) also have high CO2 content and will benefit from knowledge gained from the Gorgon program.
US and Australian officials said data accumulated in projects approved at the meeting will help reduce the costs of carbon capture and storage, currently estimated at $100/tonne of carbon, to $20/tonne or less.
