Q&A No.715 - Use of these new drill pipes with gas tight connections

0 votes
Dear colleagues,

I looked at the new catalogs of NOV Grant Prideco and Vallourec, and saw these new drill pipes (DP) with gas tight connections.


Vallourec: Express M2M;

The use of DP as DST strings will make RIH and POOH much faster than using production strings with premium connections (since we use the iron roughneck to makeup and breakup the connections).

It could be a big cost reduction on the DST test depending of the rental prices of these new strings.

Have any of you, already used these DP with gas tight conn. or any similar one ??


Nelson Nishimura

asked Jun 8, 2016 in WTN by Nelson Nishimura (220 points)
edited Jun 9, 2016 by Nelson Nishimura

4 Answers

0 votes
Hi Nelson,

I have used 4.0" XT-M 39 and 4.5" XT-M 46 S-135 DP for 3 x DSTs for Statoil, and have planned to use it on a further 3 DSTs for Husky.

Once had a connection pass pressure test then later leak but once we replaced the connection and re-tourqued no issue.  I believe it work great.  Will need to diligently ensure make up torque Iron Rough neck is checked and suggest minimal dope.

Ensure you check if you have H2S as the pipe may not be suitably rated for H2S if expected.


answered Jun 9, 2016 by Bill Jackman (140 points)
Thanks Bill!
0 votes

In around 2014 we used to rent out two strings of  3 1/2" XTM 39 Drillpipe 15.50 pounds per foot to Shell in the East of the UK for Underbalanced Drilling operations.

The Drillpipe Connections had a metal seal feature which was very reliable. The drillpipe was put through very harsh conditions which resulted in very heavy tooljoint wear, at some points the box OD,s were almost worn through but we never had a failure.

For DST work I can see this pipe as a benfeit to the operation as it is easy to handle and run .Varying OD,s and ID,s make selection for DST operations very flexible.

Although you have an Iron Roughneck I would make sure run procedures are well known and documented especially if you have to fall back onto manual make up.We had issues with Casing Crew trying to shoulder out joints.




answered Jun 10, 2016 by Colin Griffiths (140 points)
Thanks for your response Colin, much appreciated.
0 votes

Nelson - below is a response from one of our Registered Non-members, Chris White, MD of Signspread Ltd:

My immediate reaction to using this new type of gas sealing DP for DSTs, is that time savings running/retrieving the test string using this special DP would only be achievable if the DP string was used to actually drill the reservoir section.  Most rigs provide the drill strings as part of their package, so there would almost certainly be an added rental cost involved covering the provision of the special gas-tight seal DP which would apply from a couple of weeks before the well is spudded, to allow time for the string to be cleaned and inspected, consequently a full drill string rental charge would apply for more than the duration of well drilling, coring, logging, testing, and possibly suspension.

I would strongly caution against using tubulars which have been subject to drilling stresses (applied torque and tensile loads) as a production string, which is what a DST string is by definition.  Additionally, the internal wall of the DP will not be clean, especially as it will probably be used to cement through.  Using the Iron Roughneck to make/break connections is an obvious time saver, however nearly all DST Downhole Tool connections are now 3½” PH-6 Hydril which has a much lower make-up torque than 3½” DP connections. Consequently, tubing tongs will still be required to accurately torque the finer threads of those components.  Personal experience has taught that mixing multiple thread types and torques in the same string almost always leads to a lost time event.

It has been proven many times that using specialised and dedicated equipment improves performance by reducing down-time which drives down costs.  Commonly, DSTs are performed in a cemented Liner, so if operations are planned correctly, the tubing test string can be run in singles, pressure tested, and retrieved and racked in stands while other operations like waiting on cement, and offloading, spotting, and hooking-up the surface Well Test Package, are ongoing.  If you are fortunate enough to be using a dual-derrick drilling unit, the dedicated test string can be assembled and tested using the offline derrick which can also be used to make up sub-assemblies of DST tools.

If you need any assistance planning your well evaluation operations, please feel free to contact me.

Best regards

Chris White

answered Jun 13, 2016 by Fiona Curley (1,480 points)
0 votes

No, sorry, nor have we technically evaluated the potential use of these drill pipes for production type operations.

BP has purchased test strings (4.5-in and 5.5-in premium tubulars, and pup joints) and would recommend their use.

With dual derrick rig operations, tubulars can be made up in stands offline, and therefore rig operational time is optimised.

The QA from the make-up torque-turn graphs is also useful assurance when running the test string, not sure if this can be supplied for DP connections made up with Iron roughneck.

Best wishes, Rob
answered Jun 13, 2016 by Robert Ingham (180 points)