Well, sadly this is a contribution to the rotting of sox! I was hoping PAX would demonstrate how everything should be done without hitch first time around. Actually, any substantial project will have it's hiccups.
A second cleanup with no reason given? Since the well is cased along it's full length (including the slotted section) the problem can't be a cave in.
I can only make a guess at the most likely reason: that inflows were not quite what was expected. This is not a disaster but it is a nuisance. The process of drilling using muds can sometimes have the side effects of these muds penetrating the surface (yes, becomes mudcake!) and reducing the well performance if the initial cleanup was not thorough. This can easily happen if drilling proceeds in an over balanced situation (where the mud column pressure is greater than that of the formation fluid in the sandstone). After all, the sandstone is very permeable. There are various techniques available for lifting off the filter cake (if any) by drawdown of well pressure or other cleanup processes with different degrees of efficiency. They will no doubt play that by ear step by step.
BB. I don't think they've tried that one - Can you elongate yourself in cartoon fashion with your brush in hand and shoot down the well? You might have to be on a hefty rubber band and perhaps need to hold your breath for a bit.
Juke
PAX Price at posting:
11.9¢ Sentiment: Buy Disclosure: Held