Re: Hot Rock question from newbie
- From: Aidan Karley <firstname_lastname@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
- Date: Thu, 14 Dec 2006 22:33:31 GMT
In article <5bwfh.15444$HV6.12496@xxxxxxxxxxxxxxxxxxxx>, Clive Douglas
wrote:
Roughly how long will it take to drill down to 6 miles in depth. Is a6 miles = 36,000 ft.
hole diameter of 300mm in the "normal" range???
Deepest that I've drilled was to a measured depth of 28,000ft
(vertical depth was about 8,000 IIRC ... where'd I put that survey ...
nope, got one for BD42S2, but that was a year or two later ... search,
search, nope, too far in the past), which took about 4 months to get to
that depth from a kick-off at 19,000-something. So getting to 36,000
would be expected to take in excess of a year.
The German KTB-1 and KTB-2 (Kontinental TiefBohrung, Continental
Deep Bore) drilled to 9101m (29,850ft) over 5½ years between 1987 and
1994.
http://www.icdp-online.de/contenido/icdp/front_content.php?idcat=1180
The deepest hole ever drilled was the Kola Superdeep well which
took 19 years to get to 40,200 ft. The ICDP site has posted more of their
data since I last looked.
http://www.icdp-online.de/contenido/icdp/front_content.php?idcat=695 If
you want more, you'll need better Russian than mine. Poccki yazik ,
konechno.
Hole diameters decrease as you go deeper, because you drill the
well with a bit of one diameter, then have to line the hole with steel
"casing" pipe of smaller outside and inside diameters, then drill ahead
with another bit of yet smaller diameter. 4.5" (114mm) is the smallest
diameter bit used regularly for making new hole ; it'll drill out from 5"
casing [YES, I do know there are lots of considerations in selecting your
grade and wall thickness of casing.]. 5" casing needs a 6" drill bit.
6" drill bits require 7" casing, which requires a 8½" drill bit.
8½" drill bits require 9.5/8" casing, which requires a 12¼" drill bit.
12¼" drill bits need 13.3/8" casing, which needs a 15½~17" drill bit.
16" drill bits needs 20" casing, which needs a 26" drill bit.
26" drill bits needs 30" casing, which needs a 36" drill bit.
36" drill bits needs 42" casing, which needs a filthy great pile-driver.
I'm glossing over a *lot* of detail - the local "new" university
does an MSc in drilling engineering, which you can spend about 4 years
doing, if you want the really gory details.
--
Aidan Karley, FGS,
Aberdeen, Scotland
A light wave is more like a crime wave than a water wave.
.
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- From: Clive Douglas
- Re: Hot Rock question from newbie
- From: Aidan Karley
- Re: Hot Rock question from newbie
- From: Aidan Karley
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- From: Clive Douglas
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