kockatea, page-27

Looks to me that we might have formation damage from the fracking fluid not being inhibited enough. The water in the fluid reacts with time on the clays in the formation, causing swelling and blocking off of the fractures.
See for example;

http://www.nuenergen.com/index.php/information/nuenergen-blog/propane-backing-fracking-process-with-environmentally-safe-alter/

http://seekingalpha.com/article/325972-gasfrac-energy-unlocking-new-hydrocarbon-liquid-basins