It basically refers to the thickness of the oil bearing Sands,...

It basically refers to the thickness of the oil bearing Sands, reservoir quality & HC saturation (eg: xx feet of net pay with low oil saturation & High water saturation etc).

Gamma ray from the MWD tool can see the Sand from the Shale, while the Resistivity tool picks up any spike from HC's compared to the water in the drilling mud used for drilling. So the MWD tool gives a quick interp & if all is good, then they the Wellsite Geo informs the Driller to stop drilling, circulate bottoms-up, trip out the drillpipes out of the hole, rigup & run Wireline tools & collect fluid samples, take pressure readings etc before any formation damage sets in from the mud filtrate. If there r no shows, then keep drilling towards next target. 

Not sure what their P90 estimate was & whether the 144 mmbbls net to 88E was for all the Targets mapped out in this well. Check slide 16-17 on their Winx presentaiton about the basin floor 'Fan' in the Torok. Drilling results from this aren't out yet so that could b on their next update.