Scott discusses this in the 3-Jan shareholder briefing specifically for approx. 4min from 33m53s to 38m15s.
Time stamped link
here.
But to be fair, he generally puts the sticking issue more down to the differential pressure and the likely high permeability zones, which as you've mentioned are associated with differential sticking and not necessarily the expansive clays.
A few more relevant points that I took out of this video (the times shown below are hyperlinks to that part of the video)...
7.05min“…we're going to be re-looking at the mud system. I think that's one of the things that's contributed to some of the issues that we've had with some of the sticky hole conditions and degradation in the borehole and again this is all about learning what the rocks respond to with the mud system…”
17.40min“…with some of the differential sticking - again, of the cable on the wall and the tool on the wall generally indicates some reasonable permeability for that to occur…”
47.32min“…we had some sticking of the drill pipe as well when we were pulling out of the hole.
Again - often indications of good permeability because when you've got higher mud weight in the hole than when you do in the well bore it wants to flow from high pressure to low pressure. I
f you've got impermeable rock that doesn't happen. But where you've got permeable rock that's where you get that differential sticking. So with the drill pipe beginning to stick, running casing is going to cause us some issues and again that's a that's a lesson learned now for the next set of wells and we'll be able to find our mud weights in the particular horizons. We did have much better drilling performance with the side track with the lower mud weight. We didn't encounter any losses in the inthe Pebbly Arkose. But once the borehole started to degrade and that mud cake started to break down and the borehole started to breakdown, in some of those what looked like more permeable intervals, that would cause us some significant issues. We would have likely got the liner stuck and again that that that then adds further complications on top of it...”
