Comment by Animats

The real news here is that Fervo has made progress in deep drilling. Deep geothermal has been known for decades but almost nobody can get down there. Fervo got down to 15,000 feet in 16 drilling days last year with a test well in Texas. 500F heat. That's where it gets useful.

This new one is apparently not as deep but fans out with horizontal drilling. Next step is presumably deep and horizontal fan-out, but the hype and TechCrunch are too vague to tell.

Big, cheap synthetic diamonds help. The classic Hughes drill bit, the thing which looks like a set of bevel gears, is not really a cutter at all. It's a rock-crusher. The weight of the drill string on those pointy rotating teeth crushes rock into dust. Modern diamond drill bits are brutally simple things that claw through rock.[2] Fervo says they got 3200 feet on one drill before they had to pull it out. The less often that has to be done, the cheaper deep drilling becomes.

There's probably a really good description of what Fervo is doing in some publication for oil drillers. TechCrunch isn't it.

[1] https://fervoenergy.com/fervo-energy-pushes-envelope/

[2] https://fervoenergy.com/how-modern-drill-bits-are-accelerati...