Re your point of "are we talking Heavy Duty rig or conventional rig " for the next phase. I'm not sure, so long as it's gutsy. I'm inclined to think the rig used at the start on Hab.2 was probably quite gutsy. Here are some excepts, from old ASX reports, which would seem to confirm this.
You can go to GDY website and look up these reports from the start of Hab.2 drilling and you will see something like this-:
Report 26/7/04. H2 on track, 13" casing set @ 631m. ( I think 13" is a mistake, but?) Report 10/8/04. H2 @ 2,233m. 9-5/8" casing set in. Report 23/8/04. H2 @3,200m. Drilling '8-1/2" 'hole'. Report 6/9/04 Reached hot granite @3,682m. 7" casing to be set. Report 16/9/04. Casing set. 610m of 6" open hole remains to be drilled ahead.
You can see from these brief excerpts that the rig they were using at that point was well capable of drilling large dia. holes. I would think they could have proceeded on with the 8-1/2" bit they had running in the 23/8/04 report until they got close to the point of encountering the high pressure, 5,000psi, water reservoir. At that point they must go to the snubbed drilling rig and use the 'underbalanced' drilling technique. Using high pressure water( just below the pressure of the water in the rocks, hence 'underbalanced') now as the lubricant /cooling medium as well as to carry drilling swarf back up to the top of the hole, instead of using mud which experience has shown fouls up the porosity of the heat exchanger.
This means the snubber drill unit ideally wants to be capable of drilling an 8-1/2" hole as well way down there. I don't know if the unit being used recently could have done that or not? (They were drilling in 6") Anyone know this?
boppy.- Not really knowing what I'm talking about you may be able to extrap. a bit for me on the way sizing is actually stated in drilling. ie. There is talk of drilling at a certain size, then casing at a certain size, then drilling on again at some reduced size. I'm not sure where the dimensions actually refer to. eg. With a 9-5/8" casing, are they refering to the outside dia.or inside dia. (bore). I guess if they are using an 8-1/2" bit that means it drills an 8-1/2" hole. Likewise I suppose a 4" drill pipe is 4" outside dia. even though pipe, where used to convey liquids or gasses are referred to by their inside measurements, logically enough. So can you help me on any of this? I rave on with all this as one really needs to know to follow the reports meaningfully.
geojac
RNE Price at posting:
0.0¢ Sentiment: Buy Disclosure: Not Held
