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Problems jetting out jackup legs in GoM
07 December 2010
** WE ARE PLEASED to POST THIS on BEHALF of a colleague in GoM **

The Spartan 151 has been unsuccessfully trying to pull legs for over two weeks now. They were able to get 1 leg free, but are still battling the others.( It is a 150 H class independent leg cantilever, with triangular truss type legs.) The rig is in the Breton sound area”¦

Apparently the jetting system is insufficient in this area, and they have a javeler pump excavating at the can. They are jetting at 18 BPM with two strings of drill pipe (One angled in from a liftboat). They have the starboard leg free, the port leg is stuck. The bow leg generally not much of a problem so said.

Water depth is 14 feet and penetration was 64´ on the port leg. The jet lines on the rig can handle a maximum of about 300 psi going through the can.

Any suggestions would be helpful!

Kind regards

Dave Taylor
Site moderator
10 answer(s)
PaulHowlett
CEO
Sudelac
Total Posts: 80
Join Date: 10/04/08
Guys, this is not my area of expertise (if in fact I have one), but several days ago I saw the stuck leg issue and since I have not heard any news of success so thought I'd drop you my thoughts, as obvious as it might seem. As you are so shallow and cannot ballast down beyond the recommended depth to get more pull, how about attaching some of those bouyancy balloons I have seen in the past to the legs below the water line and then pumping air into them to get more pull on the individual leg, just my thoughts, sorry if its not practical. Paul Howlett, Sudelac Ltd
bhavnani.pankaj
Drilling Engineer
Geodynamics
Total Posts: 1
Join Date: 23/02/11
We had a similar problem in one of our jack up rigs in india
As far as i remember we asked the driling fluids engineer to provide detergent and thst we pumped around the legs and spud cans
We got the legs to come out within a day
Augusto
Consultant [retired Shell staff]
SPREADAssociates
Total Posts: 228
Join Date: 02/09/05
Quote:
Originally Posted by http://www.rigzone.com/news/article.asp?a_id=46310
Rita Sticks Jack-up Leg in Sea Floor, Bisso Gets It OutBisso Marine Co., Inc.|Tuesday, June 12, 2007


Continuing with the efforts to clean up Hurricane Rita damage, the Bisso Marine salvage team extracted the first of three Letourneau, Inc., 84 class leg and can sections that remain penetrated into the sea floor of the Gulf of Mexico. The 130-foot-long leg and can sections each has 425 tons of steel weight. The three 84 class leg and can sections are in 230 feet of water, and each has 82 feet of penetration.
In late 2005, while using the D/B Boaz, Bisso Marine had previously removed approximately 235 feet of leg from each of the three 84 class legs that protruded into the water column near the surface and were viewed as a possible hazard to navigation by their owner. Since early 2006, Bisso has been working in a collaborative effort with the rig owner to assemble a Bisso-designed barge having the capability to physically pull the leg and can sections from their deeply penetrated location. The Barge 415 is designed with a maximum pull of 3,000 tons over the stern and has a side lift capability of 5,000 tons.

With 1,600 tons of force, Barge 415 supported by the Boaz together were able to successfully stand the first 30-foot x 30-foot square 84 Class leg section from an angle of approximately 45 degrees to a completely vertical position. Once vertical, the Barge 415 applied a force of between 2,000 and 2,500 tons, depending on the sea state, until the leg and the 46-foot-diameter can were suspended in the water column clear of the sea floor. To assist the pulling efforts of the Barge 415, the Boaz conducted airlifting and jetting operations using high volume/high pressure air compressors. The operation took seven days of pulling, airlifting and jetting to stand the leg and can to a vertical position and to extract. The first 130-foot section was transported to a temporary wet storage location in the immediate vicinity until the other two sections are extracted at which time all three will be transported to a permanent reefing location.

Bisso has also mobilized several of its custom designed 10 x 6, 4 stage, "Super Jet Pumps" to the salvage location to assist in the extrication process. Each of the Bisso "Super Jet Pumps" is a self-contained, crash-caged, skid-mounted portable unit capable of delivering 2,800 GPM at 1,150 PSI at the nozzle tip. The "Super Jet Pumps" are each powered by 1,600 HP Cummins KTA50.

Bisso is under contract to extract and transport a total of 15 LeTourneau, Inc. designed legs with cans to various reef locations. The 15 LeTourneau, Inc. legs and cans are a combination of (6) 116-C Class, (3) 116 Class, (3) 84 Class and (3) 52 Class. The water depths range between 155 feet and 320 feet at five separate locations across the Gulf of Mexico.
NicholasA
Consultant
SPREADAssociates
Total Posts: 10
Join Date: 26/06/11
Hi David,
There is a similar problem ongoing in Nigeria.The penetration is shallow but the jetting system is not good enough to release the forward leg.
After talking between ourselves we came up with the idea ( last resort) of hooking up an air line to try and channel air to surface. If air can permeate then fluid should be able to follow.This may be of help . Nothing ventured nothing gained .
Godd luck

Regards

Nicholas J Appleyard
barber_s
Drilling Supv
Hess Corporation
Total Posts: 3
Join Date: 06/04/08
You can alternate rig air and seawater, even try soap pills. If the spud can is covered with mud , you can jet with drill pipe using a crane aand a joint of pipe with a open nozzle bit. Also as Doug mentioned, try to ballast down the other sides and pull maximum. Sometimes it is helpful to pull and release in 30/5 minute intervals. I would imagine you have plugged nozzles or a plugged/leaking jet line.
Augusto
Consultant [retired Shell staff]
SPREADAssociates
Total Posts: 228
Join Date: 02/09/05
Perhaps Exxon and Glomar Adriatic XI can share their similar experience, back in 1996 (Irish Sea).
cnduncan
Drilling Consultant
SPREADAssociates
Total Posts: 25
Join Date: 10/04/11
Hi,
I was just trawling through the discussions and although this one is quite old I will offer something up for further discussion or perhaps shooting down.

I have never doen this but what about using compressed air as a jetting aid instead of water? Air in the water is not so good for rig buoyancy but injected at depth near the spud can it might free things up as it comes to surface. I have done reverse circulating air lift drilling and it is really quite effective so an air lift to help recover the legs may work OK.

Regards
Craig
edwin.damasena
Drilling Superintendent
Vestigo
Total Posts: 14
Join Date: 31/10/07
If force and hydraulics do not work perhaps mechanical means will.
JU Nautilus offshore Kolkata had that same problem long long time ago.
They organised a crane barge with some excavotor like frame with two scooping fan like device to remove the clay on top of the can. Before that they tried a HO through the rotary and pulled the string sideways to jet the soil on top of the can.
The excavator like equipment apparently used extensively in the GoM to speed up JU getting out of the cyclone path. If your case is in GoM I'm surprised they have not come accross the excavator? Unless the javeler pump is the same thing?
Rgrds

Edwin "Ed" Damasena
Drilling Mgr
Serica
Jakarta, Indonesia
Scott_McNeil
Consultant
SPREADAssociates
Total Posts: 101
Join Date: 05/03/08
I've had to do what Doug suggested a couple of times.

Be aware that if it works, the release can be quite sudden and violent (7 psi on an awful lot of square inches!) - I'm presuming they have downmanned already?

They will also have to check that none of the trusses have been damaged.

I'm guessing that the water has opened up a clear path to the sea bed which is not being enlarged any more.

The object is to destabilise the seabed as much as possible, so there are a few things that they could try.

One is to check the volume of the hole from the spud can to seabed (using LCM or dye as a marker) and then spot fresh water in the hole to try and destabilise the clay / shale as much as possible.

Alternatively, spot water that has been salt saturated - try and dry out the formation and destabilise it that way.

If they haven't tried, then pumping something abrasive (walnut shells etc) to try and open up the hole might work.

Or they could spot a really hi-vis pill, let it gel up for a while and then start pumping again - again the idea is to try and force the water to take a different route to surface.

With respect to the lift boat, they have a bit more flexibility - on the string that they are using, (if they haven't already) put a divertor tool of some sort on the bottom - get the flow going sideways as much as possible.

If none of that works, then they will have to consider cutting the leg off - which will be an akward operation in that water depth as I'm pretty sure the jack housing will be longer than 14'.

Let us know how it works out!

Scott McNeill
Snr Drilling Supv / Drilling Mgr
DougP
Retired
Marathon Oil
Total Posts: 16
Join Date: 18/08/05
I have not worked with BMC 150's with truss type legs but did have extensive experience with this rig type with tubular 12' diameter legs. We worked offshore Saudi Arabia and had several occasions where the one of the aft legs was difficult to get free. The jetting system we had was also ineffective and the only way we managed to get free on a couple of occasions was to pull the hull further down into the water (further than the recommended maximum!).

With very shallow water this would require close checking of bending forces on the stuck leg - look at adding maximum ballast on Starboard and forward so that the rig will remain relatively level when you pull down on the Port Aft.

I believe the hull is 18' to Main Deck - we pulled it down to 16' draft a couple of times! In 14' water depth that is not really an option, but you should be able to try 14'.

Doug Pirie
Drilling Mgr
Marathon Oil
Jakarta
Indonesia
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