Has the world reached its maximum production of petroleum, about 85 million barrels a day? Some energy analysts, including Carbondale’s Randy Udall, contend that the world has or will very soon smack up against inherent limits.

The concept has been called peak oil, although some people prefer the image of a mesa top, suggesting an extended period when production holds steady despite increased demand.

Some contend that the United States reached maximum production in the early 1970s, and although production from Alaska’s Prudhoe Bay temporarily spiked numbers, the decades-long story has been of slow decline.

But not all analysts believe world production limits have been reached. Jeremy Boak, project manager for the Colorado Energy Research Institute at the Colorado School of Mines, finds less certainty. He reports a range of somewhere between 2005 - 2070, but with the highest probability of peak production occurring in 2017.

What all seem to agree upon is that the easiest oil deposits have been extracted.

The result has been extraction from more unconventional locations – and with greater difficulty and cost in doing so. Examples include wells deep below the ocean in the Gulf of Mexico as well as off the coast of Brazil. Another example is Canada’s tar sands, now the leading source of imported oil into the United States.

Another potential is the so-called oil shales of Western Colorado. The bull’s eye for the richest deposits is southwest of Meeker in the Piceance Basin.

Several companies have been working to develop technologies that would more efficiently remove the hydrocarbons from the source rock. Unlike conventional oil deposits, these hydrocarbons have had neither the pressure nor heat necessary to complete the process of formation into oil.

Boak, who puts together an annual conference devoted to oil shale that attracts hundreds of people, reports that several companies continue their research, although Royal Dutch Shell has slowed its efforts.

– Allen Best