"For the application in EGS drilling, this device uses a metallic waveguide to carry the
millimeter wave (MMW) beam to a standoff distance from the crystalline rock. Argon gas is
used as the waveguide fill medium due to its ability to stay transparent to MMW’s at such
deep depths and thus higher pressures [12]. Purge gas is also used to pump out the excess
material that has been transformed into smaller particles (Figure 2.4). "
As a former geologist involved in drilling, thats going to get real expensive, real fast, in terms relative to regular mechanical drilling thanks to the requirement for argon. Perhaps theres an economically efficient changeover point at depth as mechanical drilling becomes less capable due to increasingly plastic deformation.
tomtom1337 8 hours ago [-]
You mean the argon gas used as medium specifically? I assume the purge gas is something else, cheaper?
anakaine 8 hours ago [-]
If the goal is to simply purge the content of the hole, compressed air is typically sufficient. That said, the wider the hole, and the deeper it is, the harder it is to lift material on air.
To be clear though, I'd love to have one of these rigs on my old project and compare rate of progression and hole quality. Particularly when establishing the hole in sedimentary gravels and clays. I imagine casing will still be required.
One thing that I'd be concerned about is the ability to collect samples if most of the material is being vaporised or melted. Similarly, the cooking of the side of the hole on the way down could make geophysical responses much more difficult to interpret. Sonic velocity would probably increase, televised would probably be harder to interpret, harder to spot hydrothermal infill in sedimentary cover, would it affect gamma tools (probably not)
Edit: also wondering how the hole holds up around aquifers. Does the super heating cause wall instability immediately above the non geothermal aquifers as superheated steam is created? How does this affect the hole stability if we are not casing?
Edit 2: if we are not casing, how does the hole hold up around aquifer sands, loose fill, fractured or brecciated mass?
Edit 3: Also! Do we ream open the top of the hole to down past the last aquifers before the geothermal horizon? If not, how are we stopping stopping aquifers interplay and interaquifer contamination?
tomtom1337 7 hours ago [-]
Great response! I'm just a layman here (former material scientist) but it's fun to think about this stuff!
mzhaase 7 hours ago [-]
Maybe you could hook up a mass spectrometer to the purge gas to get real time composition.
"For the application in EGS drilling, this device uses a metallic waveguide to carry the millimeter wave (MMW) beam to a standoff distance from the crystalline rock. Argon gas is used as the waveguide fill medium due to its ability to stay transparent to MMW’s at such deep depths and thus higher pressures [12]. Purge gas is also used to pump out the excess material that has been transformed into smaller particles (Figure 2.4). "
As a former geologist involved in drilling, thats going to get real expensive, real fast, in terms relative to regular mechanical drilling thanks to the requirement for argon. Perhaps theres an economically efficient changeover point at depth as mechanical drilling becomes less capable due to increasingly plastic deformation.
To be clear though, I'd love to have one of these rigs on my old project and compare rate of progression and hole quality. Particularly when establishing the hole in sedimentary gravels and clays. I imagine casing will still be required.
One thing that I'd be concerned about is the ability to collect samples if most of the material is being vaporised or melted. Similarly, the cooking of the side of the hole on the way down could make geophysical responses much more difficult to interpret. Sonic velocity would probably increase, televised would probably be harder to interpret, harder to spot hydrothermal infill in sedimentary cover, would it affect gamma tools (probably not)
Edit: also wondering how the hole holds up around aquifers. Does the super heating cause wall instability immediately above the non geothermal aquifers as superheated steam is created? How does this affect the hole stability if we are not casing?
Edit 2: if we are not casing, how does the hole hold up around aquifer sands, loose fill, fractured or brecciated mass?
Edit 3: Also! Do we ream open the top of the hole to down past the last aquifers before the geothermal horizon? If not, how are we stopping stopping aquifers interplay and interaquifer contamination?
Nice article on an earlier demo: https://newatlas.com/energy/quaise-energy-millimeter-wave-dr... ; linked from this (nice but lots lots of ads): https://newatlas.com/energy/quaise-energy-millimeter-wave-dr... .
Company https://www.quaise.com/ on YT https://www.youtube.com/@quaise
MS thesis (2024; browsable) on the vitrified wall, for that and its intro: https://www.proquest.com/openview/624989df3cdd8055a6cee9affc...
Search for papers "Millimeter Wave Drilling for Deep Geothermal Energy Production" https://scholar.google.com/scholar?hl=en&as_sdt=0%2C33&q=Mil...
Very interesting application of radio waves.