If I was working for Invictus, I would at least request an...

If I was working for Invictus, I would at least request an estimate of the cost, and with Exalo's permission send drawings of the rig mud system etc.

Consider how difficult it might be to avoid excessive mud filtrate loss and formation damage in the upper zones of the Lower Angwa if the pore pressure ramps up rapidly at depths below 4000m.

in addition, given that a flushed zone like the PA would be depleted with respect to hydrocarbon bearing zones, a MPD system has has a definite advantage by avoiding the risk of differential sticking.