Anyway, seems like the obvious solution is to stack multiple drill bits at the end and detach ones that get used up. Obviously this doesn’t work, but it’s not clear to me why it shouldn’t.
Now you might ask, cool so just drill around it.
The problem is that with current technology, you HAVE to pull back to the surface first in order to do this. You need to cement the bottom of the current hole and depending on the circumstances, you also need to set a 'whipstock' in order to assist in drilling out of the original hole. Side tracking is a long and arduous process that involves numerous trips out of the hole.
So regarding your lower comment, that's why we can't just have multiple bits and drill around them, or drop them off in their own sidetrack. It's not a bad idea, it's just that the realities of drilling at these depths are harsh and not completely intuitive.
My Creds - currently in the gulf of mexico drilling a well with a total depth of 30,012 feet.
Drilling 6 miles vertically without using a media to conduct cuttings to the surface would be a major change in how things work. I don't think that glassing the inside of the borehole by fusing cuttings as you drill will create a durable borehole. We used to have problems with electronics desoldering at depth in our MWD tools. It gets hot and the pressures can be enormous.
Former Scumbagger MWD engineer here.
You're completely right doodlebug, our MD is around 30,000 with a TVD of about 26,000' (ballparking here so i'm not violating any contracts).
I also appreciate your other comments here!
So I wrote a longer, more meandering reply to explain the other one. I'm deleting that one too. Too much stuff. Suffice to say that my time with them was interesting, not fun, full of organizational dysfunction on levels I never thought possible. I hope you are having a nice career with them. I cut mine short to save my own sanity and everything else that I loved and cared about.
Life is full of new experiences. Every day finds you at another node on the decision tree that will ultimately define and document your life to others. Pick the wrong path and your options at the next node will be less attractive than those behind you. Pick the right path and you can continue like branches on a hackberry, making the most of every opportunity to continue growing toward the light.
Had I followed the path that vengeful rage had offered me I would never have had the opportunities to polish my skills and grow my career into a successful consultancy. They got off easy because I chose to take the long view for my family's sake and chose to let it slide while taking every opportunity to find another job. If I had let it be personal then a lot of things would be different.
Geothermal power is indeed cool, but to get it usable anywhere on Earth instead of a few places where magma currents happen to be near the surface, we'll probably need several orders of magnitude deeper and wider holes than we're currently capable of drilling just for starters. Can these guys do the job? Maybe, but let's just say I'm not planning to invest in them.
[0] https://www.quaise.energy/news/from-lab-to-field-testing
That's what bothers me about this. If drilling with microwaves works, why aren't there industrial applications? Laser cutters are widely used, from little ones that engrave plastic to big ones that cut steel plate. Yet nobody seems to be selling microwave cutters. In industrial applications, you don't even have to fit the microwave generator into the hole and keep it working in a hostile environment.
The idea was suggested back in 2002, but seems to have gone nowhere.
[1] https://www.researchgate.net/publication/11075717_The_Microw...
This wants to dump a lot of heat into a large area, and there’s industrial uses for that: https://industrialmicrowave.com/industrial-microwave-heating...
You also have a device at home that uses microwaves for heating larger volumes of material…
We just have to be more selective with the location to ensure that there is heat nearer the surface. They're right, if you drill deep enough, it's hot everywhere. Even in non-geothermal oil and gas wells, we commonly have temperatures that exceed 250 degrees Fahrenheit. Our tools that we send down whole are commonly rated for 300-350 degree temperatures. Plenty of temperature down there!
Although I admit, I'm an oil and gas guy and don't really have any industry knowledge of geothermal.
Actual answer seems to be drilling side holes also involves removing the pipe. https://news.ycombinator.com/item?id=43371776
Is the failure mode they always or often fall off the shank into the hole and they can’t be extracted?
Which suggests just leaving the old drill bit somewhere in the ground. But currently doing that would also involve removing the pipe, as to why: https://news.ycombinator.com/item?id=43371776
The actual way to avoid the problem is by using bits whose design lifetime in the formation you're drilling is at least as long as the hole section you're planning to drill.