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Drift mandrel OD size used for 9-5/8" 53.5# casing
25 January 2021
Dear Colleagues,  
 
I'd like to have some information about what OD size of drift mandrel would be used for 9-5/8" 53.5# casing.
Three choices would be available.
(1) API Standard Drift: 8.379" OD
(2) API Alternative Drift: 8.500"OD
(3) (Company-specified) Special Drift

Is there anyone who uses (3) Special Drift for 9-5/8" 53.5# casing?

We usually use (3) Special Drift, which is 8.531" (= 8.5" + 1/32"). - 1/32" means OD tolerance for 8-1/2"OD rock bit.

I understand (2) API Alternative Drift is normally used if 8-1/2" bit is run.  
However, I'd like to know if there is anyone who sticks to 1/32", which is rock bit OD tolerance, for drift mandrel size even though nominal casing ID (8.535") is larger than 8.531", which is the theoretical maximum bit OD.

Any feedback would be appreciated.

Regards,
Hide
12 answer(s)
Scott_McNeil
Consultant
SPREAD Associates
Total Posts: 167
Join Date: 05/03/08
Hi Regis,

The OD tolerance is dependant on bit type and size.

Basically the OD tolerance for Rock Bits is 0, +ve while for PDC & Diamond bits, it's -ve, 0.

http://www.rock-drill-bit.com/api-standards.html

All the best

Scott
Regis STUDER
Well Construction Lead
DrillScan
Total Posts: 27
Join Date: 27/02/16
Hi Hideaki

To my knowledge bit OD manufacturing tolerance has alway been [+0, -1/32in].
Opened to see this postulate challenged though.

Régis

SASchultz
Operations Manager / HPHT Drilling Superintendent
SPREAD Associates
Total Posts: 8
Join Date: 08/04/18
Hide-san,

Just saying, be pragmatic for the purpose.

To accept what was purchased, drift as per that agreed in the purchase agreement specifications.

Most importantly, prior to use, going in the hole, drift for the maximum i.d. needed for the anticipated tools one will be running in that casing or tubing, and record that.

In all cases, physically measure the drift to make absolutely sure the drift mandrel is the actual diameter and length you need it to be, prior to use. If it's a lot of casing or tubing to drift, check the drift measurements mid-job.

Kind regards,
Allan
Augusto
Consultant [retired Shell staff]
SPREAD Associates
Total Posts: 284
Join Date: 02/09/05
I believe we are not giving the due importance to the connection chosen but MAINLY how the pin thread is cut.
If the threading machine is index on the OD of the pipe, you are bound to have more problems than if you index the lathe on the ID of the pipe. There is a publication by Nippon Steel, based on data coming from Oman.
People forget that the Wall thickness of the casing is not uniform meaning that the ID is NOT concentric with OD!

Anyhow the special drift attraction is the extra length of the drift mandrel. Because of that should always be spacified.


HideakiTsukui
Well Operations Manager
Japex
Total Posts: 7
Join Date: 21/02/18
Thank you everyone !!

I understand no one has taken into account bit OD tolerance for drift OD size. However, drift length (longer than API standard) might be worth consideration.

Regards,
Hide
Hstapl
Consultant ( sort of retired but keeping in touch )
SPREAD Associates
Total Posts: 43
Join Date: 27/03/11
The other issues with any drift has always been the OD. Was it originally manufactured to the correct OD and within the tolerance specification. Without checking I think the tolerance was plus 0.005”.
Do you have a certificate?
is the drift serial numbered ?
Do you have a certificate of test OD measurement of the drift within the last 6 months or preferably before the start of your drift inspection?
Another issue is temperature! I had this argument in the early ‘70’s. We had tested a selection of casing, pups, tools to be made up for a completion, all passed. We had used a tested and recorded drift.
The completion company called the customer to complain they did not drift. Outcome was that their drift had sat outside in the sun all day and had grown in size, outwith specification.
So all round, as others have advised, a number of things to consider, write down in detail in a specification to be used by all. This is from when the tubing is manufactured or as part of a purchase specification.
Regards Howard
Scott_McNeil
Consultant
SPREAD Associates
Total Posts: 167
Join Date: 05/03/08
Hide-San,

I agree with the other posters that you have to ensure that the casing specs and drift criteria are agreed with the manufacturer (or stockist) upfront.

For 9 5/8" 53.5 lb/ft casing, in my experience it has always been ordered as special / alternative drift to 8.500".

We then used an 8.500" drift on the casing which was at least 12" long to meet API specs, although if the drift was having to be manufactured from scratch, I usually specify 24".

The reason for not taking into account the OD tolerance of a rock bit, was that there was sufficient 'give' in the bearing pack that the bit would pass through 8.500" without damage (had many discussions with bit manufacturers about this back then).

Back in the 80's and 90's, ID tolerance was always a concern for this OD/weight combination (also for 13 3/8" 72 lb/ft) and drift failures were not uncommon.

But I've been assured by Operator casing specialists in the last few years that the casing manufacturing process has been improved to the extent that even if you don't actually order the 53.5 lb/ft as 'special/alternative drift', it should still pass an 8.500" OD drift because the mill will use as little steel as possible to maximise their profit.

Having said that, I've not been brave enough to NOT include the 'alternative drift' phrase when ordering!

Oh, and to answer your original question, I don't recall ever using a drift that did take into account the OD tolerance of a rock bit.

Have you talked with your bit provider(s) about the 'give' in their bearing packs, as these days it might not be the case?

All the best

Scott
Punch
Managing director Punch Energy Services
Punch Energy Services
Total Posts: 21
Join Date: 24/06/20
Hi all,

Good input from Allan.

You have to specify what you require. If you will drill an 8.500" hole section after running 9.5/8"-53.50# weight casing. You want to have casing ordered/allocated which suits this requirement, i.e. 8.500" SD spec pipe.

As mentioned by Dave as well the length of the drift mandrel can vary. With Shell the requirement in the quality plan was; 12" long mandrels are used for casing sizes, 6" for liners and 42" for tubing. That is deviating a bit from the API standard. Meaning if you want to get, e.g., 5" tubing drifted with a 42" long mandrel, it will have to be agreed in a quality plan or shall be clear as a requirement on the purchase order send to the manufacturer/supplier. 

In addition can only recommend, sure you do, is to have all equipment properly measured before running. E.g. make it mandatory that the bit supplier also puts a ring gauge over the bit prior sending it out to your rig. But again, would still get someone accountable on the rig to measure it prior running.

Best regards,

Marcel de Klerk




HideakiTsukui
Well Operations Manager
Japex
Total Posts: 7
Join Date: 21/02/18
Allan-san,

Thank you for your reply.
In your comment which is "API drift for that casing is 8.379" therefore requiring a special drift larger than API specified for that casing.", what does "special drift larger than API specified for that casing" mean? API Alternative Drift (8.500"OD) or Company-specified Special Drift (larger than 8.500"OD, ex. 8.531"OD which considers 1/32" rock bit OD tolerance)?

Regards,
Hide
SASchultz
Operations Manager / HPHT Drilling Superintendent
SPREAD Associates
Total Posts: 8
Join Date: 08/04/18
Dear Hide-san,

One drifts the casing for whatever purpose drives the drift i.d. requirement. A lot of operators use 9 5/8" 53.5 # casing and drill 8.5" hole afterward. API drift for that casing is 8.379" therefore requiring a special drift larger than API specified for that casing.

As Dave-san mentioned, a specific drift length is also part of the drift dimension criteria. Here is a link to an article I just grabbed off a Google search; Microsoft Word - drift-005 (hunting-intl.com)

Also note their reference, "The latest edition of the following documents shall form part of this specification: 2.1.1 API Specification 5CT 2.1.2 API RP5A5"

One should also take note that drifts wear down after a lot of use therefore the drift dimensions must be checked prior to use, to ensure they are what they need to be.

Kind regards,
Allan

HideakiTsukui
Well Operations Manager
Japex
Total Posts: 7
Join Date: 21/02/18
Dave-san,

Thank you for your comment.
Do you remember how much your specified drift OD was larger than API standard drift OD?

I’ll be happy if you have such information.

Regards,
Hide
admin
Managing Director (rp-squared.com)
Relentless Pursuit Of Perfection Ltd.
Total Posts: 488
Join Date: 10/01/05
Dear Hide-san

I'm sorry that no-one has yet responded to your discussion.

I do recall, when working for Shell UK in the 80s, that we would often go for the special drift.  From memory, not all the joints passed this criterion, because we not only specified the OD of the drift but also its length.

I hope that other members, who have a fresher memory than me, will contribute to this thread.

Kind regards

Dave
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