September 13-20, 2004

International study confirms viability of Weyburn field for long-term CO2 storage

A four-year, $40-million (Cdn) international study led by the Petroleum Technology Research Centre (PTRC) in Regina has concluded that geological conditions in the Weyburn oil field in southeastern Saskatchewan are favourable for long-term storage of carbon dioxide (CO2). The study findings were presented at the recent international Greenhouse Gas Control Technologies Conference in Vancouver.

"The Weyburn project was the first large-scale study ever conducted in the world of the geological storage of CO2 in a partially depleted oil field," explained Mike Monea, executive director of the PTRC. "While there are numerous large commercial CO2-enhanced oil recovery operations globally, there are none that have undertaken the depth and extent of research that we have."

The PTRC carried out the multidisciplinary study under the auspices of the International Energy Agency Greenhouse Gas (IEA GHG) research and development program. The Centre worked in close collaboration with Calgary-based EnCana, operator of the 50-year-old Weyburn field.

"We are encouraged by the results," said Gerry Protti, EnCana's executive vice-president of corporate relations. "At Weyburn, we are demonstrating every day that oil production can be enhanced in an environmentally responsible manner. We are pleased to have been part of this collaborative, international project involving industry, governments and researchers."

The Weyburn oil field has stored an estimated five million tonnes of CO2 over the IEA GHG project life - equivalent to taking about one million cars off the road for one year. The CO2 is supplied through a 325-kilometre pipeline from Dakota Gasification Company's coal-gasification plant at Beulah, North Dakota.

"The IEA GHG Weyburn project is good news for addressing climate change because it proves that you can safely store 5,000 tonnes of CO2 per day in the ground rather than venting the greenhouse gas into the atmosphere," explained Malcolm Wilson, an international energy specialist with the PTRC and one of the founders of the project.

The Weyburn field was selected for the study because detailed geological records and core samples, as well as almost 50 years of production history, were readily available. Some 380 million barrels of oil have been produced from the field since it was discovered in 1954.

During the study, researchers conducted a long-term risk assessment, completed geological and seismic studies, matched reservoir modeling against actual results, and performed repeated and frequent sampling to understand chemical reactions occurring in the reservoir.

The IEA GHG Weyburn study was able to:

- utilize seismic surveys to "see" the CO2 flow within the geological formations and mix with the oil reserves;

- develop a model to predict the storage capacity of the reservoir and match results over time with the model;

- predict, in a risk assessment model, that most of the CO2 will remain in the reservoir in which it is injected, with a small amount sinking to even lower levels underground over the 5,000 years following the end of the project; and

- conclude that the CO2 would never reach or penetrate overlying potable water zones or the atmosphere above ground level.

"Although we're very excited with these conclusions, we believe there's much more work to be done to determine how our techniques and systems can be applied from the Weyburn geological formation to other formations around the world, to make CO2 storage a real option for reducing our greenhouse gas emissions worldwide," Wilson said.

The Greenhouse Gas Control Technologies Conference, where the report was released, is the first international gathering of its kind ever held in Canada, drawing expert academics, scientists and policy-makers from around the world. The previous conference was held in Kyoto, Japan, in 2002.

Through Natural Resources Canada (NRCan), the federal government contributed $6 million to the study, while the Saskatchewan government contributed approximately $2.2 million to the project through Saskatchewan Industry and Resources' Saskatchewan Petroleum Research Incentive. These agencies were among the 15 public and private-sector institutions that funded the study. Other contributing institutions included the United States Department of Energy, the Alberta Energy Research Institute and the European community. Along with EnCana, industry participants included BP, ChevronTexaco, Dakota Gasification Company, ENAA (Japan), Nexen, SaskPower, TransAlta and Total (France). Altogether, the project involved 24 research and consulting organizations in Canada, Europe and the United States.

More information is available from Joe Ralko, IEA GHG Weyburn Project, Regina, 306/539-9270.

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