Sunday, December 13, 2009

I realize I'm not a geothermal expert, but if there were 'small improvements'

that would make hard-rock drilling easy and economical, wouldn't people who have to drill this stuff all the time like, oh, oil companies, be trying it? Or would it be forbidden by the Green Energy Fairy to ask them about such things?
The project’s apparent collapse comes a day after Swiss government officials permanently shut down a similar project in Basel, because of the damaging earthquakes it produced in 2006 and 2007.
...
In fact, AltaRock immediately ran into snags with its drilling, repeatedly snapping off bits in shallow formations called caprock. The project’s safety was also under review at the Energy Department after federal officials said the company had not been entirely forthcoming about the earthquakes produced in Basel in making the case for the Geysers project.
Yeah, people in Californicated might be a bit touchy about things affecting earthquakes and such...

Update: Link there now.

7 comments:

Unknown said...

Link?   Please.

Firehand said...

Link there now. Dammit, I hate it when I do that!

Keith said...

I agree there is a lot of simillar tecnology already available in the oil industry, but transferring it to hard impermeable rocks in active areas is never going to be straight forward. Geothermal is in its infancy, only Iceland has it well developed.

The theoretical effects of fluid pressure on faults has been known for many years (back to Carl Terzaghi at least, if not even back to Mohr & Coulomb. even seasonal rains can induce fault movement.

Records of actually causing quakes by injecting fluids goes back to about the 1940s with deep injection of contaminated waste water from chemical weapons manuf. at the Rocky Mountain Arsenal.

I've always thought Yellowstone would be a good site for Geothermal power, and lots of it to bleed the heat and gasses of the thing before it builds enough up for its next eruption.

Unknown said...

Firehand said...
    Link there now.


Thanks!
.

Bob Wallace said...

I believe that the diameter holes needed for oil and geothermal are greatly different. Simply upsizing oil drills has not been adequate.

There are additional problems of drilling through harder rock and in higher temperatures.

One company, Baker Hughes is attempting to make geothermal drills by engineering out all the non-metal components in the drills. Under the higher heat conditions plastic seals melt.

http://online.wsj.com/article/SB10001424052748704825504574580361710978836.html?mod=googlenews_wsj

Additionally there is a problem with drill bits dulling. It can take 24 hours to extract a dull bit and replace it with a sharp one.

Two companies/organizations are taking a different approach and using heat to spallate the rock rather than drilling it.

Potter drilling (MIT origin)is using hot water. (Good video)

http://www.studiocruz.com/secondary-pages/animation-spallation.html

Tobias Rothenfluh at the Institute for Process Engineering is using an underwater flame system.

http://www.sciencedaily.com/releases/2009/09/090912144809.htm

Firehand said...

Hmmm. I'd thought oil drilling did involve a lot of impermeable rock, so thought more of the tech would work in the other area. And no, I hadn't considered the higher temperature factor; yeah, some stuff won't work real well above a certain level.

I'd think Yellowstone would be great for the purpose: geothermal energy AND making enviroweenie heads pop, all at once!

Robert, I'll check out those links, thank you!

Bob Wallace said...

I'm not sure about the hole diameter difference, but believe it to be larger than what is needed for oil extraction.

Remember that as you make modest increases in diameter you make large increases in circumference and greatly increase the amount of friction between drill bit and rock. If you've drilled small holes and large holes through wood/metal with a hand drill you probably have first hand experience with that.

Googling for something on hole diameter I just found this interesting page. It seems that the rock that needs to be penetrated could be harder than that drilled for oil.

http://www.abc.net.au/quantum/info/hotroctx.htm