"There still is a large amount of delineation drilling to do, or basically just appraising and figuring out where the sweet spots are," Andy McConn said in an interview published Friday by the Financial Post.
The Alberta Geological Survey estimates the Duvernay shale reserve area holds more than 440 trillion cubic feet of natural gas and nearly 62 billion barrels of oil.
The newspaper reports energy company Encana Corp. plans to spend more than $500 million on exploratory operations in the Duvernay region.
Chevron said it was encouraged by its preliminary efforts in Duvernay, which it described as a source of future growth for its Canadian operations.
"They [Chevron] haven't given hard plans yet, but that's a key domino to fall in the [reserve area's] progression for one company of Chevron's size and ability to come and say we're going to push it," McConn said.
The Post reports it's expensive to operate in the Duvernay shale play.
McConn said the terms of land contracts for energy companies working in Canada are longer than for rival reserve areas in the United States. That means it may take awhile to determine where Duvernay stands in terms of North American shale potential, he said.