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I've worked in oil and gas for years. It's possible the article is missing a bunch of details, but I'm extremely dubious of their idea. First, how do they plan
by ufmace 4y ago
I've worked in oil and gas for years. It's possible the article is missing a bunch of details, but I'm extremely dubious of their idea.
First, how do they plan to address well control? As you drill down through the Earth, you drill through many layers of rock, some of which contain oil and gas in various quantities. Since the thousands of feet of rock above is heavy, they are under a lot of pressure, and will be happy to flow out through your borehole and up to the surface if you don't take measures to keep the formation under control. If they are allowed to do that, those flammable materials can easily ignite and cause a fire big enough to destroy your entire drilling apparatus and be very difficult to put out. Note that you don't necessarily need enough oil and gas to be commercially produceable to generate a disastrously bad blowout.
Oil wells address this by filling the borehole with drilling fluid at a specific density, which produces enough pressure at the bottom of the hole to counter formation pressure. Every well is also fitted with multiple blowout preventers to seal off the well in case of a sudden pressure increase from the formation, and also allow heaver weight fluid to be circulated in to get back under control. The wells are also drilled and cased in sections, so that there is never too large of an amount of borehole uncovered that needs to be kept under control.
So given all that, exactly where is this Gyrotron going to be? If it's at the surface, how are they planning to microwave through miles of drilling fluid and have enough energy at the bottom to cut more rock? If it's at depth, how is this Gyrotron going to survive the high temperatures there? High-end electronics are much more sensitive to extreme heat than drill bits are. Especially if you're pumping ~megawatts of energy through them to actually cut rock. Speaking of, how would we even get that much electric power down there? Oil and gas has spent many billions of dollars on this and has yet to find a good solution.
Also, how are they planning to keep this whole straight and judge depth? Holes thousands of feet down don't just stay straight, you have to actively keep them straight. The oilfield has plenty of ways to do this with conventional drilling hardware, how will their Gyrotron system manage it? And we also need to transport rock cuttings / fumes to the surface fast enough to support the drilling rate, how will they do that?
I'm also wondering about fluid flowrates. If they manage to drill down far enough to get to rock hot enough, how much fluid do they need to flow in order to get enough heat energy to the surface to operate these steam turbines? How big pipes do they need up and down to flow that rate? They also need to flow slow enough at depth to pick up lots of heat, and also fast enough through the mid and shallow depths to not lose all that heat to the local formation before it gets to the surface. For that matter, what's the heat flow rate from the magma into the rock at the depth they were drilling out - how much heat power can we really extract long-term with their setup? (I see jjk166 has addressed that, and that it is another serious issue).
Don't get me wrong, geothermal is a really nice solution, and I wish all the luck in the world to anyone working on using it more. I just don't see any technology here that address the real issues with getting large-scale energy from geothermal.
- Mizza 4y agoI think the idea is to use a traditional drilling technique to start the whole until they are past any gas pockets, then use the beams after that. The beam drilling doesn't require fluid, and the process itself creates a glass wall/lavatube on the side of the hole. They drill quite slowly relative to traditional drilling to evacuate the ash and fumes, but they don't need to replace the drill head so the overall process is faster.
- ufmace 4y agoStill sounds rather dubious. I dunno about this whole thing about the beam creating a protective glass wall, but I'll give them a pass on that. Also on how they'd actually evacuate all the fluid and how they'd extract ash and fumes without it. The most critical part sounds like heat. It's very hot down there, and we're also presumably running megawatts of electrical power for this beam, which all goes to more heat. Ambient temps at those depths may be over 300 F / 150C, and that's before we pump in megawatts of extra heat with no way to extract it. I helped design and operate lots of oilfield electronics for those depths and temperatures. MTBF for the most hardened electronics we could get our hands on at temps over 150C was in the neighborhood of 200 hours max. Drilling slowly with much more sophisticated and unproven electronics, I expect they'll be dropping like flies if they ever work at all. And that's with extremely generous assumptions on the heat loads. MTBF of electronics drops exponentially as temperature goes up.
- jasamer 4y agoThe plan seems to be to have the gyrotron that generates the drilling beam on the surface, so the electronics don't have to withstand any heat at all. The "only" need to manage to get a beam that's clean enough that it reaches 20km into the ground.
- ufmace 4y agoCuriously, the other people who responded all think it'll be downhole. Anyways, this does make the device heat practical to handle, but now you have to figure out how you're going to get the vaporized rock out and shoot your microwave laser thing through 20km of rock vapors. And we're also presuming you can keep 20km of borehole exposed to atmospheric pressure with only this supposedly glass wall thing preventing formation fluids from flooding the borehole. If that cracks anywhere and floods it with high pressure hydrocarbons, maybe you could seal it up before all of your surface hardware gets blown up, but what do you do next? Oil wells have procedures for how to circulate heavier fluid back in to get the well back under control, but I have no idea how you fix a failed glass wall thing.