"GRAND JUNCTION, Colo.—Chevron Corp. is giving up its experimental oil shale lease in northwest Colorado, saying it wants to free up its resources for other priorities."

"The company is working with the Bureau of Land Management to figure out what to do with the lease, including possibly transferring it to another company, The Grand Junction Sentinel (http://bit.ly/xeTXVx [2]) reported Tuesday.

Getting petroleum-like substances out of mined oil shale is tougher than pumping oil out of traditional wells. Companies haven't found an economical way to do it in the U.S.

Chevron had been studying using carbon dioxide to draw out kerogen, a petroleum-like substance, from rock. The company said in a statement that the research was "productive."

The announcement comes as the Interior Department is considering reducing the area where oil shale research could be conducted in Colorado, Utah and Wyoming. The administration of George W. Bush opened up 1.9 million acres to oil shale research in 2007, but the Interior Department is looking at reducing that area to as few as 32,640 acres."

The Associated Press had the story February 28, 2012. [3]