a
Login | Contact Us | Site Map | Paid archives | Alerts | Electronic edition | Subscribe to the paper
Subscribe

Seebach: Shell's ingenious approach to oil shale is pretty slick

Saturday, September 3, 2005

Story Tools

When oil prices last touched record highs - actually, after adjusting for inflation we're not there yet, but given the effects of Hurricane Katrina, we probably will be soon - politicians' response was more hype than hope. Oil shale in Colorado! Tar sands in Alberta! OPEC be damned!

Remember the Carter-era Synfuels Corp. debacle? It was a response to the '70s energy shortages, closed down in 1985 after accomplishing essentially nothing at great expense, which is pretty much a description of what usually happens when the government tries to take over something that the private sector can do better. Private actors are, after all, spending their own money.

Since 1981, Shell researchers at the company's division of "unconventional resources" have been spending their own money trying to figure out how to get usable energy out of oil shale. Judging by the presentation the Rocky Mountain News heard this week, they think they've got it.

Shell's method, which it calls "in situ conversion," is simplicity itself in concept but exquisitely ingenious in execution. Terry O'Connor, a vice president for external and regulatory affairs at Shell Exploration and Production, explained how it's done (and they have done it, in several test projects):

Drill shafts into the oil-bearing rock. Drop heaters down the shaft. Cook the rock until the hydrocarbons boil off, the lightest and most desirable first. Collect them.

Please note, you don't have to go looking for oil fields when you're brewing your own.

On one small test plot about 20 feet by 35 feet, on land Shell owns, they started heating the rock in early 2004. "Product" - about one-third natural gas, two-thirds light crude - began to appear in September 2004. They turned the heaters off about a month ago, after harvesting about 1,500 barrels of oil.

While we were trying to do the math, O'Connor told us the answers. Upwards of a million barrels an acre, a billion barrels a square mile. And the oil shale formation in the Green River Basin, most of which is in Colorado, covers more than a thousand square miles - the largest fossil fuel deposits in the world.

Wow.

They don't need subsidies; the process should be commercially feasible with world oil prices at $30 a barrel. The energy balance is favorable; under a conservative life-cycle analysis, it should yield 3.5 units of energy for every 1 unit used in production. The process recovers about 10 times as much oil as mining the rock and crushing and cooking it at the surface, and it's a more desirable grade. Reclamation is easier because the only thing that comes to the surface is the oil you want.

And we've hardly gotten to the really ingenious part yet. While the rock is cooking, at about 650 or 750 degrees Fahrenheit, how do you keep the hydrocarbons from contaminating ground water? Why, you build an ice wall around the whole thing. As O'Connor said, it's counterintuitive.

But ice is impermeable to water. So around the perimeter of the productive site, you drill lots more shafts, only 8 to 12 feet apart, put in piping, and pump refrigerants through it. The water in the ground around the shafts freezes, and eventually forms a 20- to 30-foot ice barrier around the site.

Next you take the water out of the ground inside the ice wall, turn up the heat, and then sit back and harvest the oil until it stops coming in useful quantities. When production drops, it falls off rather quickly.

That's an advantage over ordinary wells, which very gradually get less productive as they age.

Then you pump the water back in. (Well, not necessarily the same water, which has moved on to other uses.) It's hot down there so the water flashes into steam, picking up loose chemicals in the process. Collect the steam, strip the gunk out of it, repeat until the water comes out clean. Then you can turn off the heaters and the chillers and move on to the next plot (even saving one or two of the sides of the ice wall, if you want to be thrifty about it).

Most of the best territory for this astonishing process is on land under the control of the Bureau of Land Management. Shell has applied for a research and development lease on 160 acres of BLM land, which could be approved by February. That project would be on a large enough scale so design of a commercial facility could begin.

The 2005 energy bill altered some provisions of the 1920 Minerals Leasing Act that were a deterrent to large-scale development, and also laid out a 30-month timetable for establishing federal regulations governing commercial leasing.

Shell has been deliberately low-key about their R&D, wanting to avoid the hype, and the disappointment, that surrounded the last oil-shale boom. But O'Connor said the results have been sufficiently encouraging they are gradually getting more open. Starting next week, they will be holding public hearings in northwest Colorado.

I'll say it again. Wow.

Linda Seebach is an editorial writer for the News. She can be reached by telephone at (303) 892-2519 or by e-mail at .

Comments

Post your comment (Requires free registration.)

Comments are the sole responsibility of the person posting them. You agree not to post comments that are off topic, defamatory, obscene, abusive, threatening or an invasion of privacy. Violators may be banned. Click here for our full user agreement.




(Forgotten your password?)




News Tip

Know about something we should be reporting? Tell us about it.

Reprints