Ann: Preliminary Wireline results shows Multiple Potential Zones, page-596

What would low permeability look like? The first indication would be having to sit on points with the RCI/RCX tool (with standard probe) and wait for long periods for the pressure to stabilize at formation pressure. If the point is very low perm/tight then you would usually abandon the point as it won't reach formation pressure in a month of Sundays. Sampling very low perm/tight points is usually a waste of time unless youre using the special kit and even then you usually have to wait long periods for fluid flows to clean up.
Sometimes a point might slowly reach formation pressure but then the pressure tracks above expected formation pressure...this is what we call a supercharged point. Because tight formation doesn't attract a thick sealing layer of mudcake like permeable formation does the fluid component of the drilling mud (filtrate) is pumped into the formation and charges it up. They may have a large diameter probe which might increase their chances of getting valid pressures in low perm rock..this would normally be run along with the normal probe...you then have the option of using either probe.

There'll be a permeability value at which the economics of well become questionable. Fracking is an option for very low perm/tight formation but that's a whole different ball game.....eg more wells required for production and life of producing wells is relatively short.