[BITList] Riser Tensioners (Ruckers)

[FS]

Now I know Im going crazy, in deeper water the pneumatic multi-cored 
umbilical line was replaced with  Electric umbilical lines with sonar 
last resort backup the sub-sea electronic controllers were a nightmare 
to maintain as they were filled with an insulating fluid which had to be 
vacuumed for 36hours to make sure all the bubbles were out before the 
unit could be sent sub-sea again due to the hydostacic pressures the 
units were subjected to
frank

On 1/11/2010 7:15 AM, fs wrote:
> The Larger yellow units are for the riser and the Smaller units are 
> for the BOP (blow out preventer) and are also used as guides for the 
> sub-sea TV assembly ,before one unlatches the riser the drill pipe is 
> pulled and layed down, if time does not allow for the pipe to be 
> pulled the shear rams in the BOP are activated which cuts the pipe At 
> the BOP and allows for the pipe to be pulled to the surface and layed 
> down the BOP Holding lines are then unlatched (Depending on the depth 
> the BOP is operated using ether a pneumatic multi-cored umbilical line 
> or in deep water (1000ft plus where pneumatics are no longer fast 
> enough ) by sonar signals to a sub-sea controller mounted on the 
> stack) allowing the vessel to move off location. Normally the riser is 
> then also pulled and layed down if conditions allow, it gets very 
> interestingly when one try's to go back onto location and re-enter the 
> well being drilled even more so if flotation riser is being used 
> because of deep water. When the BOP and ball joint is being run a 
> sub-sea sonar beacons are attached to them along with a attached 
> captive buoy which can be theoretically be released  by sending a 
> coded sub-sea signal to it, the odds of a false signal being received 
> is up in the millions, but while drilling in the straights of Taiwan 
> we were for ever having to jump the divers to repack it after the buoy 
> popped up in the moonpool or along side depending on the tides, only 
> happened in Taiwan though
> frank
>
> On 1/11/2010 4:57 AM, HUGH wrote:
>> Very interesting stuff.  A blast from the past - the yellow 
>> stabilisers are Riser Tensioners, attached bottom end to the 
>> structure round the moonpool, one at each corner, and top end to a 
>> wire rope round the top of a pulley that goes down to the slip joint 
>> whence the riser casing round the drill string is supported.  The 
>> pulley sits on a ram that slides inside the cylinder.  These are 
>> quick response (or were, last time I was involved with them on a 
>> vessel like the one on the photo) pneumatic/hydraulic very high 
>> pressure.  When the ship falls they reel in, and when she rises they 
>> reel out, at least that's the theory, so they only operate between 
>> these limits.  The object is to isolate the riser from ship movement 
>> up and down - shock absorbers or stabilisers, if you like.  As far as 
>> I recall, if seas are bigger than the designed range, the riser is 
>> disconnected from the blowout preventer on the sea bed and just hangs 
>> there till conditions improve.  Don't ask me what happens to the 
>> drill string.
>> Hugh.
>>
>>
>> _______________________________________________
>> To unsubscribe from this email List, send an email to:
>> BITList-unsubscribe at lists.bcn.mythic-beasts.com
>>
>> BITList mailing list
>> BITList at lists.bcn.mythic-beasts.com
>> http://lists.bcn.mythic-beasts.com/mailman/listinfo/bitlist
>>
>>    
>
>
> _______________________________________________
> To unsubscribe from this email List, send an email to:
> BITList-unsubscribe at lists.bcn.mythic-beasts.com
>
> BITList mailing list
> BITList at lists.bcn.mythic-beasts.com
> http://lists.bcn.mythic-beasts.com/mailman/listinfo/bitlist
>
>    
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.bcn.mythic-beasts.com/pipermail/bitlist/attachments/20100111/0beb48d7/attachment.shtml