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Use of drilling stand
22 June 2011
Hi folks

We are having a heated debate at our Workshop about whether or not we should use a drilling stand (c/w 15k FOSV) for our HPHT well.

The discussion hinges around the potential need to use a kill/kick assy, which will need to be M/U to the drillstring.

In the event of needing to use the kill/kick assy, it's essential that there are suitable barriers on the inside of the drillstring prior to breaking off the top-drive. We discussed the (relatively) common practice of using non-ported double floats in the drillstring .. but these are generally untested and so do not constitute a barrier.

So, the question is :
1. What does your company do and why ?
2. Is there a way to test the floats such that they can be considered a barrier ? (one idea that springs to mind is a test against pipe rams and the casing before drilling out the shoe, but this cannot be done for subsequent assemblies).
3. What about coring assemblies ?

Right, over to you all.

Kind regards

Dave
9 answer(s)
PaulHowlett
CEO
Sudelac
Total Posts: 81
Join Date: 10/04/08
You could consider using a drilling stand and have drill string well control valves of your preferred design on site and test them regularly during the operations. This can be done off-line off the critical path using a purpose built test stand. One such design is the Sudelac SubCHECKER PT Test Stand. This same stand can save time during the regular BOP tests by testing all the other drill string well control subs off line too. Info sheet attached. Hope that's not considered too sale-sy!!!
JDDrouin
QA/QC Subsea Wellhead Specialist
SPREADAssociates
Total Posts: 86
Join Date: 06/05/09
Dave,

I cannot answer all three but can provide feedback on number 2.

2. Is there a way to test the floats such that they can be considered a barrier ? (one idea that springs to mind is a test against pipe rams and the casing before drilling out the shoe, but this cannot be done for subsequent assemblies).

First off, it's going to depend on the definition of "barrier", which may already have been established by the operator.  And my guess is they're going to respond in one of two ways ... 'no under any circumstances' or 'let's talk about it'.

Secondly, the float manufacturer needs to be the lead agency in certifying the test ... and my guess is that they're going to be highly reluctant to take on that liability (and I've been down that road).

Hope that helps.
SCollard
Director
Welltrain Limited
Total Posts: 4
Join Date: 09/12/09
For those interested in a little more background on this issue please find attached a paper prepared as a handout for HPHT Well Control and Well Engineering courses.  

Cheers

Steve

[email protected]
Documents uploaded by user:
The HPHT Drilling Stand Conundrum.pdf
Scott_McNeil
Consultant
SPREADAssociates
Total Posts: 101
Join Date: 05/03/08
Hi Dave,

This was a subject for 'spirited' discussion on a remote location HPHT Well I did a few years ago.

As with Neil, I was unconvinced that using a drilling stand was actually safer than drilling without it.

Ultimately the drilling contractor insisted, so we went with it.

If the same thing came up again, I'd go with tested spring type floats. As long as you can plan ahead, it should be simple enough to make up a test assembly that can be used on the Rig.

With respect to coring with float valves, many years ago I was using a ball drop sub to drop coring balls in high inclination wells.

The sub was positioned just above the core barrel and was activated by increasing the flow rate to shear out some pins - the change in DP pressure confirmed the ball had gone and dropped into the seat.

It wasn't 100% reliable (sometimes the ball went early if we had to ream to bottom), but good enough.

I'm afraid I cannot remember who made it, though I have a vague recollection it was actually a Liner Hanger Company we got it from!

Best Regards

Scott
admin
Managing Director (rp-squared.com)
Relentless Pursuit Of Perfection Ltd.
Total Posts: 377
Join Date: 10/01/05
This has cropped up again in 2017 and I was wondering (hoping) that you could all read the original thread and then respond with any updated comments that you might have
olakolsen
drilling supervisor
Statoil
Total Posts: 4
Join Date: 22/03/08
We drilled several HPHT wells in the 80's. Same question. Solution: Installed a 15k kellycock below the drilling stand. This had to be boken out and placed1 stand up at every connection. Result: Full pressure integrity ! (strip back, close kelly cock & install kick stand)
PS: I would not trust floats unless no other option was available.
Good luck. Regards. Ola
AndrewLough
HPHT Senior Drilling Eng
Maersk Oil
Total Posts: 1
Join Date: 22/11/09
Colleagues,

As per other replies we don't use a drilling stand but use double floats in the BHA. These are tested onshore prior to sending to rig. On any trip out of the hole the insert valve is changed out for a new one and we have a small volume HP pump to re-test prior to running.

Hope this helps

Andy
Michael.Zambonini
Hess Corporation
Total Posts: 2
Join Date: 07/04/08
When drilling an HPHT well in Denmark a few years back, we went through the same discussion and decided not to use the kick stand. We used double Baker floats (spring type not flapper) and had them tested in the shop prior to shipping. We then made up a test assembly so that we could test them individually on the drill floor prior to running in hole.

This worked well and is certainly more efficient than using a kick stand.
gds6ut
Drilling Supervisor
SPREADAssociates
Total Posts: 53
Join Date: 11/09/10
Drilling stand a bit oldfashioned now (and I don't believe it was ever a 'safer' way).

Double poppet floats in string - floats installed and tested in float subs onshore with certs for the pressure testing. Floats pressure tested to a nominal value.

You can core with double floats, but the floats will have to be flapper type and they must drift with the correct coring balls etc.

Neil Guthrie
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