New Maps May Unlock Giant "Heavy Oil" Reserves, Expert Says

Richard A. Lovett
for National Geographic News

March 19, 2007

Some of the world's largest—but hardest to reach—oil
reserves could be tapped with the help of a little-known scientific
field called rock physics, a Canadian scientist says.

The reserves, located north of Edmonton, Alberta, are so immense that they put Canada second only to Saudi Arabia among the world's oil-rich nations (see map of Alberta).

But the reserves contain only "heavy oil," which is extremely difficult to extract.

"Imagine taking a pile of sand, mixing it with peanut butter, and trying to get the peanut butter out," Douglas Schmitt, a geophysicist at the University of Alberta in Edmonton, said earlier this month at a meeting of the American Physical Society.

Currently the easiest way to extract the oil is to scoop up the top layers of earth in giant strip mines.

"You dig it out and put it in something like a big washing machine to separate the oil from the sand," Schmitt said.

Going deeper requires drilling, but conventional drilling techniques don't work because of the oil's thick, viscous consistency.

To make the oil less viscous, production crews commonly heat it by injecting steam into the underlying rock.

For this to be feasible, the steam must be used as efficiently as possible.

That, Schmitt says, is where rock physics comes into play, allowing scientists to chart the process with seismic mapping.

"This could be the next phase of petroleum engineering," Schmitt said.

"Instead of simply making guesses, we should be able to track where the fluids are coming from."

Oil's Seismic Signature

Seismic mapping has long been used to study underground rock in the search for potential oil-bearing formations.

To make these maps, geologists set off small explosions or use mechanical thumpers to vibrate on the surface, and then use instruments to observe how the seismic waves are scattered by underlying rocks.

Rock physics can extend the technique's usefulness by studying how porous rocks conduct seismic waves when fluids are added or removed from them, Schmitt said.

His studies have shown it's possible to map exactly what parts of the rock are being penetrated by steam—and where the largest oil reserves remain in any given rock layer.

This could allow production crews to target precisely the right areas without wasting time and costly steam on regions that have already been depleted.

Not all energy experts see heavy oils as a solution to the world's energy problems, however.

To turn the oil into gasoline, hydrogen must be used to combine the oil with natural gas, points out David Goodstein, author of Out of Gas: The End of the Age of Oil.

"It's very difficult and will always be limited," Goodstein said of the process.

But he applauds efforts to wring more oil from Canada's sandy deposits.

Only a mix of technologies can slake the world's energy thirst, he notes.

"We have to try everything we possibly can," he said.

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