With a good deal of conventional oil production becoming uneconomic at today's prices, you would think that oil majors might shelve their dreams of tapping the world's vast -- and unconventional -- oil shale reserves.

Well, Total SA (NYSE:TOT) and Royal Dutch Shell (NYSE:RDS-A) (NYSE:RDS-B) are keeping the dream alive. A few news items clue us in to the European titans' thinking.

First, it was reported in local papers that Shell has filed for industrial water rights on Colorado's Yampa River. The company holds a few leases in northwest Colorado, which shares a massive endowment of oil shale with neighbors Utah and Wyoming. The Department of the Interior pegs total recoverable oil at 800 billion barrels. Of course, the resource here is actually kerogen, not oil, and requires some serious cooking to accelerate Mother Nature's work. But that's another story.

I imagine that Shell is partially emboldened by the October expiration of a ban on oil shale development in Colorado. A similar ban was lifted just this month in the two neighboring states.

The sudden regulatory shift may also have encouraged Total, which has announced it's taking a 50% stake in another Colorado shale venture, called American Shale Oil (AMSO). The parent company of AMSO, IDT, is a microcap telecom company that I associate with calling cards rather than drill bits. I suppose if Google (NASDAQ:GOOG) can expand into geothermal and solar, these folks can get after oil shale. Interestingly, they've already brought Schlumberger (NYSE:SLB) into the fold to work on resource characterization, so Total isn't the first heavyweight to take AMSO seriously.

This isn't Total's first foray into oil shale, either. Last I heard, the French firm also had a cooperation agreement in effect with Petrobras (NYSE:PBR) spanning Africa and the Middle East. Petrobras, meanwhile, runs one of the world's few industrial oil shale operations in its native Brazil.

I wouldn't characterize these activities as an all-out rush by any means. But the majors, who are prone to taking the long view, clearly aren't letting currently depressed oil prices dash their oil shale dreams. Whether the incoming administration will slam the development door shut -- with water use and discharge being two big concerns -- remains to be seen.

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Fool contributor Toby Shute doesn't have a position in any company mentioned. The Motley Fool's disclosure policy dares to dream big.