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Solid Oil

Posted by | September 20, 2008

Pumps can extract crude oil from the Earth. That’s because crude is a liquid – sometimes a thick one, but a liquid nonetheless. But the Earth also contains some oil so stiff it’s more like solid plastic than it is like a liquid. Our Canadian neighbors have a lot of this special form of petroleum.

Solid crude has been known pretty much forever.  The ancient names for it include pitch, asphalt, bitumen and tar. Bible stories, like the one with baby Moses floating in a basket sealed with “bitumen and pitch,” show that knowledge of solid petroleum isn’t new.

In the 20th century, Canadian geologists mapped “tar sand” reserves in northern Alberta. As those who follow business news know, those tar sands are now being mined for petroleum. The shovels and trucks that are doing the work are huge even by the standards of modern mining. Each truck-load at Shell’s mine, for example, lumbers out of the pit with 400 tons of oily sand.  (That makes the payload on even the largest flat-bed dually look like a dust mite.) If you’ve seen one of our large, open pit copper mines here in the West and you multiply that memory a couple of times, you begin to understand that mining the tar sands is a large-scale operation.

The Athabasca Tar Sands, as its called, is a layer of solid oil in sandstone rock. The layer is about 50 yards thick, which doesn’t sound like so much, but it’s a hundred of miles across. Geologists think that the tar sands contain several hundred billion barrels of petroleum – a King’s ransom. It’s actually possible Canada has as much solid oil as the whole rest of the world has liquid oil.

But you can’t run an internal combustion engine on tar, and making the Canadian deposit into saleable goods isn’t as easy as distilling liquid crude. The tar sands must be processed extensively to extract liquid fuels from it. That takes a lot of water and a lot of energy. It’s a major industrial process, not a pretty tourist site.

Natural gas is one of the crucial ingredients for converting the heavy oil in Canada’s tar sands to a fully liquid fuel. As you may have noticed from last winter’s heating bill, natural gas isn’t cheap these days. So that’s a major factor for the tar sands. And, to be economically feasible, the scale of the Alberta effort is staggering. There’s a multi-billion dollar investment needed before the first barrel of oil is delivered  – that’s up to ten times more money than the development of a traditional oil field. So both energy commitments and money are limiting the development of tar sand resources.

But at the current price of petroleum, Canada’s tar sands are fully economic. That has some Americans wondering about our form of solid oil, called oil shale.

Shale is a common and drab-looking rock made of compressed mud. A few shales in the world have an organic molecule called kerogen in them. Our Green River oil shales in Wyoming, Utah and Colorado have enough kerogen in them we could potentially extract energy from them.

I have some of the Green River rocks in my office, and when I break them open with my trusty rock hammer and quickly sniff the fresh faces, I can smell the kerogen. (Sniffing rocks is one of my pastimes. I learned to like the smell of sulfur because it occurs in a lot of gold ore. There’s nothing like freshly hammered sulfur to start my day off well. But I digress.)

Geologists think there are about 80 billion barrels of crude oil equivalent in the Rocky Mountain oil shales. That’s less than what the Albertans can boast, but it’s nothing to sneeze at.

Unlike the Canadians, we are not mining our solid oil. That’s because shale is tough to process for energy. We would have to add more energy to our oil shales than the Canadians do to their tar sands to extract the kerogen and convert it to liquid fuels.

Still, given the current price of crude, oil shale is looking more economically feasible. So, depending how we sort out our global warming concerns, the younger readers of this paper may see the day that our oil shales are mined for their energy content just as the tar sands in Alberta are now.

In that case, we’ll be doing much more than sniffing the Green River rocks.