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Liner-drilling 16" (liner size)
02 December 2017
Hi folks

At one of last month's workshops, we were discussing the Well Design, which requires casing off a fairly short section that has some 'awkward' shales.  It's offshore, from a moored semi in 'moderate' water depth, relatively benign waters.

The current plan is to drill 17½" hole, run and cement a 16" drilling liner.

We then got around to discussing drilling-with-liner.  To the best of the knowledge of those in the room, this was not an available/proven technology.  So we reverted to the original scheme.

Please could members advise their experience (if any) of this technology:
  • What went well - and to assure this can be repeated
  • What didn't go well - recommendations to avoid
I'm sure that our Service Co colleagues will have something to add, but we are especially interested in learning from end-users.

Many thanks


3 answer(s)
Total Posts: 83
Join Date: 10/04/08

Dave, I strongly suspect the ability to casing drill 16" casing exists, maybe not as large as 17.5" OH as CD does not need the same hole size as drill bits and conventional casing regimes. A concern would be if this is envisaged as a 16" drilling liner currently could the liner be casing drilled in this size or would it need to be a 16" casing string, not a liner, and then require to be hung off at the casing hanger or some other profile contained within the wellbore. A conventional liner hanger system is always convenient because it does not use up a casing hanger nor need a landing ring pre-planned and can be run or not run and be set at a planned or +/- planned depth.

Managing Director (
Relentless Pursuit Of Perfection Ltd.
Total Posts: 387
Join Date: 10/01/05
Hi Peter

Thanks for the response.

A full post-well study was conducted on the cuttings/debris recovered from the well.  T

he conclusion was that it was a rheologogical effect; a shale was trapped and compressed between two totally impermeable layers and, when penetrated, flowed into the well at a rate in excess of 20 MT/day.

The best solution is to case this off as soon as possible.  The liner size needs to be 16" (well deisgn consideration) so everyone woul really like to know about experience (off a moored semi) with this liner size.

Thanks for taking the time to reply


Drilling Specialist/Well Engineer/Training Consultant
Kingdom Drilling
Total Posts: 342
Join Date: 10/01/05

Firstly are we sure there is not another solution? 

By assuring  this not perhaps 'prescription without proper diagnosis'. Where Shale-problems are often fluid, mud weight, practices, people issues that can be resolved if we truly learn first and foremost how things went wrong. Too often this is rarely the case.

If multiple well failures and liners have resulted. Where a wellbore stability study and supportive investigative analysis clearly states the physic and mechanics as to why an isolation string is evidently required.

In a benign environment (where I assume there if very little heave) and where  bumper sub could be run to counter this. The semi can be looked at akin to drilling from a jack up or even from a land rig.

Several companies have casing while drilling solutions as
SPE presentation attached. 

I also recall an article in 2002 that stated that out of 200 casing while drilling 'land based' jobs on success rate was 99%.

Therefore if conventional methods success rate in this region fall far short of such numbers what is there to loose vs gains that could readily be made.



Documents uploaded by user:
casing while drilling.pdf
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