[BigParm]

You don't have to trip if your cutting tool never wears out. You fix it to the end of a casing string and just keep adding lengths. The hole is cased as soon as it's drilled.

[cnote337]

And so when you go to cement your casing in place, you, what?, cement your brand new indestructible quaise 'drill bit' in the hole?

Sorry, I think not. Neat idea, but there's big holes in that in practice.