RE: Link to SOU LSE board Thanx for the link!
To offer some suggestions to questions, the news suggested lower mud gas readings due to higher mud weights prior to the losses. The losses might have been by a small volume since they were able to log the well under those conditions. This might suggest that the mud weight increases were higher than necessary for well control and the added hydrostatic pressure was enough to cause the overbalanced mud column to flow into the aparent permeable sandstone to some degree. After logging and placing the cement pill to cure the mud losses they are drilling ahead. It seems that mud weight can be adjusted lower as an aid to prevent the occurance of further losses if more porosity is encountered with any degree of permeability.
To penetration rates in the smaller hole size, assuming tri cone bits, penetration rates will be slower due to smaller bearing sizes in the cones of a 6 inch sized bit that will limit rotary speed in RPM. Further to that, smaller sized drill collars are pretty flexable so reduced weight on bit is necessary to aid in drilling a vertical hole. Too much weight on that dril string will cause angle building in the well and it will have a tendancy to go "directional". Also, the more overbalance the mud column is to formation pressure, then the slower the penetration rate is as well, as compared to a mud weight that is closer to being slightly but safely overbalanced to the formation pressure.
As for drilling into Parisi with this hole size, it seems a possibility and it would be beneficial to do so for the sake of logging it at the very least. To case it could be dicey and would mean a casing size somewhere in the neighborhood of 4 3/4" with a 2 3/8" production tubing string, 2" inside diameter. That tubing size might be restrictive to flow from a prolific reservoir but at this stage it would be a very good remedy to salvage this well and generate some production. This idea is somewhat out of my comfort zone of experience but I see it as do-able, all other associated issues considered. It's something that we will put into the hands of the engineers to solve.
This well is very interesting, intriguing, although I'm sure a lot of people are having other descriptive words and thoughts for it right about now.