On Tue, 1 Jul 2014 21:50:53 +0000 (UTC), "DannyD."
wrote in

bob haller wrote, on Tue, 01 Jul 2014 10:19:08 -0700:

drillers drill brand new wells, rather than make existing well deeper....

Why?

My *guess* is that to drill deeper via an existing well, the "deeper"
part will have to be a smaller diameter than the pre-existing well
casing. For example, if you want a new well with a 6" o.d. casing,
you probably have to drill with a 6.5" bit. If you want to deepen a
6" well, you can't use the 6.5" bit. You have to use something smaller
that will fit in the existing 6" pipe.
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