Sorry all, I have not been following this particular well, so I am coming in cold and are not up to speed with where they are in the drilling programme, but what you may be witnessing is the rig moving off location to run the BOP/LMRP/riser.
If they have completed their top hole sections (which are drilled riserless), then the next thing that they require to do is run the BOP/LMRP/riser, and you will never perform that over dead well centre, because if you did and you dropped the stack then you would potentially obliterate the wellhead, and require to start all over again somewhere nearby.
If the projected move of is approx 340 metres then that is greater than I would expect, but if as others say a storm is coming through then that is perhaps understandable, as it would give you a greater safety margin for inadvertently being unable to hold station.
If the storm is significant then that may delay the operation a little, until it abates, as riser sections/LMRP/BOP are all heavy lifts, and as such are exponentially more at risk to adverse sea states than standard lifts are, and in any case winds of 40 knots will shut down the cranes and prevent you from running the equipment until the conditions abate.
Like I said, I have come in cold and am not up to speed with the point in the drilling programme that they are at, and I am just passing through just now so do not have the time to research.
So please disregard this suggestion as to why the rig may have moved off of location, if my assumption of the stage in the drilling programme is incorrect.
I work out to be 24.58secs difference, so would then depend on tide, current speed and movement of rig etc .....then you would get the difference in distance....to me 24.58secs for a thing that size and whatever else you have to take into account........I 'm not worried...lol
At 0806 on 25/06/15 ER was at -52.15491 and -55.71816 then at 0933 on 25/06/15 she was at -52.15296 and -55.72213. I calculate this to be a move of approx 340m, more than she would normally do while drilling. Who knows why she has moved, probably no one on this board. But to state that she has not moved at all is plain wrong.
If peeps didn't know, at times in the South and North Poles or nearer to these areas, the Satellite coverage is not as good, so at times you could only be covered by 0, 1 or 2 Satellites. So somethimes you will not get correct fine positional sync lock and sit in course sync lock.....which will then be out by x amount of feet/meters.
Shaggy, you might want to look at the position data on 25/06/15 between 0806 and 0933 before declaring with absolute certainty that ER has not moved. She moved off station between these times and has not moved back since.
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