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Severing Drill Pipe - pipe not in tension
05 February 2016
Hi everyone,
We have made 4 attempts to sever a string 5.7/8" DP. The string is in a 17.1/2" hole, drilled at an inclination of +/- 69 degrees, using oil based mud at 1.5SG. We were not able to pull tension on the string before attempting the cuts. The first two attempts were made using a mechanical cutting tool (spinning disc which cuts the pipe circumferentially) and the second two attempts were made using a plasma cutter - all tools were sized correctly to cut the drill pipe string. To all intents and purposes, the tools appear to have functioned properly but the pipe has not parted. I am interested to hear experiences from the group around cutting pipe which is not in tension. Any replies appreciated.
Regards,
Stu


13 answer(s)
ghj_sco
Well Engineering Advisor
SPREADAssociates
Total Posts: 2
Join Date: 30/07/15
Stu,

Need to know why you can't apply tension at the cut point because you will need to be able to apply tension to pull the string out. 

At the moment, it sounds as though you are cutting below the stuck point.

Greg
Sos123
Managing director
Specialised Oilfield Services
Total Posts: 6
Join Date: 14/11/14
Hi Stu, 

there has been a few comments based on the plasma cutter, but what was the out come with the first two runs, mechanical cutters? Also it would be interesting to see the tools BHA's and also a picture of the plasma cutter after POOH? Did you see any over pull with the tools after the cut, did you try and circulate after each cut? We have experience and success with plasma tools in Tension, neutral and compression! 

If if we can be of assistance please let me know.

cheers

Martin 
Augusto
Consultant [retired Shell staff]
SPREADAssociates
Total Posts: 228
Join Date: 02/09/05
Although the string is not in tension, there are tiny sections of it which are: the base of the tool joint pins!
So if you go inside the pipe, find the tool-joint restriction and place a charge in the area of the base of the tool-joint pin, you should get the result you wish.
Idea of Shell´s Gerrit van Wilpe [email protected] - now retired. He may elect to elaborate on that, if asked.
ColinCGB
Operations Petrophysicist
Gaia Earth Sciences Ltd
Total Posts: 13
Join Date: 21/12/11

Generally, I have always (35 years) felt that having the pipe in tension helps,  and even contractors that have said that their particular tool does not require it have requested 10% overpull at the wellsite  - this includes plasma-cutters.

Anecdotally I have heard that if pipe is in compression then with a plasma-cutter the pipe can re-weld.  Seems plausible, perhaps.

I have seen good results from the Owen Split-Shot.  Fired in the connection it splits the box and allows you to pull out without actually needing to make a complete cut.

The other most common reason that I have seen for a "failure to cut"  is actually attempting to cut where the pipe is not actually free.  I have seen this happen where use of a free-point survey was dismissed and not run,  or it was run but then ignored ( "but we need to cut deeper for the side-track" )



Stewart_McGregor
Group Drilling Manager
Lundin Petroleum
Total Posts: 2
Join Date: 01/06/15
Hi Guys,

Thanks for all the replies - Ryan the only daft question is the question not asked!

We are operating on a jack up - so no heave to deal with.

We were stuck higher up and jarred out. The BHA was not coming back to surface, so we decided to cut at a place where we could recover the remaining DP then wash back down, fish the string and recover the hole. Whilst in the midst of these operations we could move the pipe freely.

Not being able to cut has changed the plan, so there is no immediate need to try the same thing again.

To answer some of the other points:

We would know if the pipe was cut as we would see the BHA weight being lost and reduction in drag when moving.

We are sure we have been cutting in the right place (i.e. not over a connection) - correlations have been done before positioning the cutters.

Plasma tools have been anchored.

It's the requirement for tension that interests, especially when using the plasma cutter... 


Regards,
Stu
JohnDrummond
Business Development Manager
SPEX GROUP
Total Posts: 4
Join Date: 04/06/15

Hi Stu,


Sorry to hear you are not having great success with your cutting operations, have you considered using a tailored Explosive Jet Cutter.

I have attached a brochure for your reference.


Good Luck

Documents uploaded by user:
Jet Cutters 190615.pdf
ianwsmith
Consultant
SPREADAssociates
Total Posts: 1
Join Date: 23/12/15

Stu,

The MCR plasma technology is reliable, however when there are issues it has been found to be job planning and job set up that have been the main issues. Not knowing the specifics of the job the questions/point I would have/make are:

Was the plasma cutter positively anchored during the cut? If not was the pipe perforated prior to making the cut? If none of these options were utilised you would most likely get movement of the cutter during the cutting phase. If this happens you will not cut the pipe.

Another point to consider is that the cutters have to be centralised to make an effective cut. Was the tool string well centralised - you have to make sure that the tool string does not naturally "bow" and cause the cutter be become de-centralised. In some cases when this happens you may get a partial cut, if this is the case then you should/may be able to circulate.

Lastly are you sure you have cut at the top most free point, I have seen many cases where a free point log has been conducted on only a small part of the stuck tool string where they are assuming they are stuck free and do not log any higher. If they had they would have encountered a higher stuck point.

have you spoken with Specialised Oilfield Services (SOS) they work closely with MCR Oil Tools - e-mail is [email protected] or [email protected]

Hope this helps any questions please give me a shout. 

Best Regards

Ian

earthrealm
well engineer
NNPC
Total Posts: 5
Join Date: 18/04/15
had good results cutting dp with this tool back in the days. 
http://www.corelab.com/owen/piperecovery-tubingdrillpipe
because of the inclination, you may not have a perfect cut, thus you may need to work the pipe a bit to complete the cut





ajessiman
Account Manager
Welltec
Total Posts: 1
Join Date: 05/02/16

Hi Stuart,

Welltec have a e-line mechanical cutter which uses grinding pads rather than cutting blade.  Able to cut in compression (tested up to 30klb) without jamming.  Leaves a clean cut (top and bottom faces) so no subsequent dressing run required, and creates very fine swarf (powder).

It's also able to cut several times per run.  Recently performed a 5" drillpipe recovery op where 23 cuts carried out, including 1 run with 7 cuts.  Drillpipe had been cemented in over 500m so was cut in 20m sections to subsequently wash over.  Deviation was >80deg; cutter was run on Well Tractor.  Can be run standalone: anchors itself in ID.

Regards,

Andy

earthrealm
well engineer
NNPC
Total Posts: 5
Join Date: 18/04/15
Very good questions by the previous commenters, especially Jecabello.
i believe you may have made a cut, but since you are unable to apply tension, you are not sure if a cut has been made?
could you state why you are unable to apply tension?,
alternatively you may consider using the segmented explosive cutter for drill pipes usually 2.5''  -- note: some explosive cutters are best positioned across a collar, than on the pipe body
ryanbellingham
Drilling Engineer
Apache
Total Posts: 2
Join Date: 04/01/12

Morning,

Daft question, fixed installation or floater?  With the mechanical cutter I could imagine slippage if you've got a bit of heave (depending on how you're compensating the rig up but with stuck pipe I'd imagine you could still be seeing half the heave downhole?)

Plasma - did you run an anchor?  If unrestrained it is possible to slip up hole just as you initiate the cut (as the cutter pushes you up the hole leading to a mis-run) you can waste the charge cutting a track/groove up the pipe rather than getting the clean cut.  If you did run one, can the eLine provider confirm the anchor held firm during the cuts on Plasma?  Possible to increase the restraining force?  Run a stronger anchor / with toolstring lying on the lowside is it holding as planned.

I've had a fair degree of success with the Spex 3-3/8" RCT (clean cut)... http://www.spex-innovation.com/spex-offshore/cutting-solutions/non-explosive-tools/

An ugly option for fishing (but potential dependant on your next step) is getting a severing tool in the hole, I have had good success when unable to apply tension (offline abandoments and prepping tubing for recovery), but not good if you need to get back onto the fish.

Another thought is centralization, how's the toolstring sitting in the hole (assuming cut depth is somewhere building up to your 69 degrees), plasma cutter would require centralization that may have been minimised to help get the toolstring down at that inclination?

Depth control - it couldn't be something daft like cutting on a tooljoint? (I struggle with that, even saying it, with 4 runs even if no correlation performed!).

Apologies if this is a much too simplistic response!  Good luck.

Ryan


Documents uploaded by user:
Radial_Cutting_Torch_070415.pdf
John_McNab
Completions & Workover Manager
SPREADAssociates
Total Posts: 10
Join Date: 11/02/10
Have you tried SPEX in Aberdeen? Andy Pettitt is the man.

http://www.spex-innovation.com/contact/

_____

Note from moderator: We don't normally encourage direct contact, because it circumvents the forum and we all lose the learning opportunity; the site was set up to SPREAD knowledge.  

However, we have let this through since a another post has referred to SPEX and John McNab is also a long-time member and clearly not sending a "sales" message.  However, if Andy Pettitt can furnish details (in a non-sales way, please) then that would be fantastic!
jecabello
Senior Well Engineer
Glencore
Total Posts: 3
Join Date: 21/11/12
Stu,
We've successfully cut 2 7/8" tubing (and drillpipe) not in tension, many times at depths ranging from 1000m to 5000m.
A few questions come to mind from your post:
Why weren't you able to pull tension on the pipe before attempting the cuts?
I'm assuming you are mechanically stuck, is this your assumption too?
How do you know you are cutting above the stuck point if you haven't put the pipe in tension?
Have you considered the possibility that you have successfully cut the pipe, but you are stuck above the cut point?

Posted by

Stewart McGregor

Group Drilling Manager

Lundin Petroleum

Total Posts: 2
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