[gtvwill]

No doubt the science has linked that to it, but you also regularly fill faults whilst drilling for core or hell even when drilling water bore holes. If the grounds crap you just pump mud with some additives in till the holes are blocked or your at least retain some pressure. I'm gonna throw it out there also, having worked amongst it most drillers/holes that are drilled...we know piss all about whats going on down there. Hell we had one hole that was LITERALLY within 50m of the side wall of an open cut mine, we drilled down past the open cuts depth from surface because our targets were for next to segments of the underground mine that went off the open cut. We lost water pressure/return for a good week, had to cart loads in and mix it plenty thick to try and plug the hole. Few weeks into the job, the other offsider went for a walk in a direction we didn't usually go for a piss, about 100m away he came across all our drilling fluid forming a small lake in the windrows above the open cut. Geologists had no clue why it had happened or why we had lost water in the first place leading up to that discovery.

The point is, drilling sure as shit isn't an exact science, you should probably be more skeptical about its effects than not. Most drillers aren't some highly educated academic that knows exactly whats going on down hole...most of them have been hired because they have the mechanical aptitude to fix just about anything that can go wrong with a rig or have the perseverance to push through the horrible conditions, both above ground and down hole to get the job done. Drilling be it through the process itself or the result of its action definitely plays a role in the problem.