That's their idea yes, but it's only an idea, and I am extremely dubious. It's much more like handwaving speculation by people who have no experience in drilling deep wells than a practical proven solution.
They're expecting the hole to be open air, with nothing at all to push back against formation pressure. It has to be, for the radiation system to work. But that means that this supposedly fused glass wall has to withstand all of the formation pressure all the way through the borehole perfectly. And they seem to be expecting this to happen from the vaporized material just condensing on the borehole walls. One little crack anywhere, and the whole borehole could flood with water or oil, possibly even blowing out at the surface. How do they recover from that? They'd have to figure out where the failure was, seal it, then get all the water out, each of which seems practically impossible.
Oh, I just thought of another issue too. A liquid well-control incident with this thing would indeed suck for the reasons given, but there's a lot of gasses down there too. What happens if there's a gas well-control incident?
It could be flammable natural gas. It may or may not burn or explode in the wellbore, since there's not going to be much oxygen down there. How about at the surface though? Flammable gas erupting out your wellbore with this system sounds very not fun. They have megawatts of electricity flowing around, do you think all of that meets industry standards for avoiding explosions in an environment of flammable gasses? I think there's high potential for a very big boom, and maybe the whole well turning into a giant blowtorch you have no way to control.
Or it could be a poisonous gas like H2S. Poisonous gasses billowing out of your wellbore with this system also sounds like a major pain.
So, who wants to come up with a practical way for this thing to deal with that too? The oilfield has proven methods for preventing it in the first place and dealing with it if it happens anyways. Trip your annular blowout preventer, evacuate the rig, and circulate heavy kill mud until the gas stops flowing.
Maybe these guys could flood the well to stop it. Which means they also need to keep many tankers full of fluid on-hand, and after it works, they're back in the initial situation of needing to figure out how to seal the leak and evacuate the fluid again. I seriously can't think of a good way to do any of that.
Yes that does seem worrying, and might explain why they've only (publicly) drilled a few inches here & there. Maybe they could give the waveguides some outer grid or fins or whatnot to give extra support?
Physical support isn't actually that important - conventional wellbores are not physically supported either until they are cased and cemented, and mostly don't have too much trouble with collapsing. What they need is a seal tight against liquid and gas to prevent it from leaking into the wellbore.
Conventional wellbores accomplish this with the hydraulic pressure of the drilling fluid. These guys can't have any fluid though, so they would have to rely entirely on this condensed rock stuff to both support against the pressure and seal against any leaks. Seems very unlikely, considering that it isn't deliberately created by any kind of process, just randomly condensed from rock vapors.
Note also that they won't really start to run into trouble with this until they get at least a few hundred feet down.
Also, you definitely aren't going to drill more than 6 inches while attempting to physically support the wellbore with any part of the drillstring or waveguide or whatever they're calling this thing.
People should also understand that oil drilling is a highly competitive multi-trillion dollar industry employing tens of thousands of smart people all around the world. Absolutely everything that anyone could think of has already been tried, and adopted if it worked and abandoned if it didn't.
They're expecting the hole to be open air, with nothing at all to push back against formation pressure. It has to be, for the radiation system to work. But that means that this supposedly fused glass wall has to withstand all of the formation pressure all the way through the borehole perfectly. And they seem to be expecting this to happen from the vaporized material just condensing on the borehole walls. One little crack anywhere, and the whole borehole could flood with water or oil, possibly even blowing out at the surface. How do they recover from that? They'd have to figure out where the failure was, seal it, then get all the water out, each of which seems practically impossible.