@mysteryman,
The windfall profits tax of the 1970s--it taxed domestically produced petroleum because it was being priced at world oil prices, even though it obviously was much cheaper for the oil companies to produce. Thanks to the effect of unintended consequences, it meant that oil companies increasingly purchased foreign oil, and spent less on exploration and exploitation of domestic sources. The tax was repealed in 1988, but the Alaskan north slope oil fields are the only large scale domestic petroleum project in the U.S.--largely because so much had already been invested in the project, including the pipeline. The oil industry just lost interest in exploration and exploitation of new sources in the United States.
I suspect the American energy industry is happy to sit on thie resource, because they can still import oil, and they have no incentive to start a project with very high capital investment requirements. If foreign, imported oil starts to get really, really expensive, and with the windfall profits tax replealed, i suspect we will then see the exploitation of these sources.