University eyes area oil fields

Published 12:01 am Saturday, November 10, 2007

NATCHEZ — Scientists from the University of Texas at Austin and the Department of Energy are very interested in an old oil field just outside Natchez.

The Department of Energy has given a $38 million grant to the University of Texas to study carbon dioxide sequestration at the Cranfield oil field outside Natchez.

Susan Hovorka a senior research scientists with the university said this study will be the first of its size in the country. While Hovorka said six similar sites will be going up around the country none will be as big as the one near Cranfield.

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“We’re very excited,” she said.

Hovorka and her fellow scientists are studying the feasibility of storing excess carbon dioxide in giant saline aquifers hundreds of feet below the earth’s surface.

Hovorka said the Cranfield site run by Denbury Resources is a prime spot to study because Denbury will be using large amounts of carbon dioxide at their oil recovery plant.

Texas based Denbury is an oil recovery group.

After locating once-used oil fields, Denbury pumps vast amounts of carbon dioxide into unused wells in order to loosen left over oil from the rocks. When the carbon dioxide is extracted it’s bound with the newly recovered oil and and ready to be refined.

And because Denbury requires so much carbon dioxide to run its facility Hovorka and her colleagues think it’s a prime locale to study.

While the same carbon dioxide that Denbury produces is the same gas that humans exhale, large quantities of it cause a build of greenhouse gases and contribute to global warming.

Hovorka said capturing Denbury’s used gas and pumping it into saline aquifers far below the earth’s surface is a tremendous benefit to the environment.

The study, expected to last about five years, is expected to set a precedent in carbon dioxide sequestration within the United States. Similar projects are already used in other countries.

“If we want to keep using the fuels we do now we have to have a way to offset them,” she said.

Hovorka said she is particularly excited to see this new technology applied on such large scale.

The Frio Brine Project, named for the Frio River, in Texas has used the same technology but on a much smaller scale.

Between 2004-2006 the Frio project was able to successfully store 2,000 tons of carbon dioxide in a saline aquifer near Huston.

In contrast Hovorka said the Denbury site once operational, should be able to put 1 million tons of carbon dioxide underground in just one year.

And while Denbury’s oil plant is not fully completed, it’s expected to be operational around January.

Hovorka said they will be ready to catch and bury gas about one year after that.

And Hovorka and her cohorts will have lots of gas to capture.

When they first begin production Denbury will be using a naturally occurring gas source near Jackson.

However once Rentech’s coal-to-oil plant is up and running, Denbury is contracted to buy all of their carbon.

Hovorka said once this multifaceted operation is running the environmental benefits will be wonderful.