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Does it really need to go 80m deep? Seems like a very deep hole

They're probably looking at a width of 10cm tops from their description.



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I was thinking more like a 10 foot wide hole, 1 mile deep.

orig. title "China Is Drilling a 10,000-Meter-Deep Hole Into Earth’s Crust", 61chrs well within 80chrs limit, Y shorten as "10k-Meter" not "10km", RSVP.

Can't believe they don't show a photo of what appears to be a 10 meter in diameter, 2.7km deep hole.

If you drill a hole deep enough, you'll be unable to prevent the hole from collapsing in on itself. I wonder how deep that would be.

A kilometer deep hole is not very cheap.

Considering that the current deepest borehole in the world is 12km [1], 20km is a lofty goal.

[1] https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole


How would you keep the hole open?

But most places that is way, way deeper than 20km.


In Otaniemi they drilled to 6.4 km and got 125C rock. https://agu.confex.com/agu/fm18/meetingapp.cgi/Paper/437325

Current deepest hole is 12 km. Temperature goes up 18 C per km. I think the hole would get quite technical if we tried to go to 70 km deep...


> They aim to have no impact at the surface by digging just about 20 feet (6 meters) in the ground.

Is 20 feet enough? I would imagine that a lot more depth would be required to support the above-ground structures.


This is more like the pressure under 150m of water.

150 deep in a mine is about 1.02 atm. You'd need to go about 30km down to get 20 atm.


That page says the well was 1285 feet (~390 meters). So, the Mir mine (525 meters) does seem deeper.

I'm far from being even slightly knowledgeable in this topic, but would it be possible to build this in very deep waters? Like a massive column containing a tunnel? Seems cheaper than digging a 1km hole.

The deepest borehole, about the size of a coffee can, is only 12km deep before the tooling started melting - can't drill with a liquid bit...

So 30km down it would be hitting liquid rock and a lot of heat.


> But you have to dig a really deep hole

Well, you can also dig a relatively shallow long trench, if you have space for it.


Pretty sure you can't make a bore that narrow and that deep without it collapsing pretty soon.

The longest wells are already close to 10 miles, but it is mostly horizontal. My understanding is going deep you eventually hit hot rock which has a clay like texture and isn’t amenable to drilling.

Core drilling is quite different from well drilling which would be used in this case.


I do not understand this article. According to wikipedia, the deepwater horizon drilled to 10,683 m in 1,259 m of water. Acccording to the nature article, the deepest ever holes drilled were successively the 2,900 and 3,200 m deep holes drilled by the Chikyu. 2,900 seems a lot less than 10,683. What is going on here?

A couple reasons, I'd bet - first, a hole wide enough to fit the probe is pretty unusual, and would be an expensive research project all on its own. Second, the probe near the surface will emit the largest signal, so you get some really good SNR data to calibrate your algorithms against. If you don't understand the signals you're receiving when it's shallow, you won't understand them any better when it's deep - a regime where we have more theories than data. Or maybe something else.

What sort of problems did you encounter drilling two 60m deep holes? How wide are they?
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