Private Forums
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


5 answer(s)
Total Posts: 108
Join Date: 05/03/08
Hi Dave,

A bit late to the party on this one, but for what it's worth;

Many years ago, a Company I was working for were using drilling liners in 7". I want to say they were using Baker, but may be wrong on that - I don't have any details as I wasn't directly involved in the project.

I looked at doing it in a similar situation to yours many years ago.

We quickly came to the conclusion that although it was theoretically possible, the main problem was the strength of the casing connection.

In our case, it had to be flush (I suspect the same may be the same with you) and it simply did not have the torque rating we were comfortable with.

I vaguely recall the Company (WFD) had several examples of drilling with liners and if I remember correctly (it was many, many moons ago) the procedure involved using a PDM locked into the shoe track to essentially provide the drilling power.

At TD, the liner was hung off and the running string recovered. The PDM could then be recovered on a Wireline, an insert Float Shoe run (on wireline) and locked into the same profile as the PDM. The Liner could then be cemented by either rerunning the Liner Hanger or by using a packer run on DP and set just inside the Liner.

Obviously this is a basically a modified DWC procedure, but it took time and had several major risk factors, which is why I suspect it disappeared rather quickly.

In recent years, I have been in several situations where a Liner has taken extensive reaming (i.e. essentially redrilling the hole) to get to bottom and had no issues.

Several Companies now do drillable PDC reamer shoes which can be adapted to drill new hole fairly easily.

But again, these are normally for 7" or 9 5/8" Liners with decent torque ratings on the Casing Connection, not the 16" you are asking about.

Best Regards

Total Posts: 2
Join Date: 24/02/18
Hello Dave
Before committing to the type of liner drilling system to be used there should be a bit of analysis around the drilling hazard that this technology is being used to mitigate. 
Some key questions are:
1. What is the section length & where is the formation of concern in the section (top, middle or bottom)
2. Are there directional requirements to be met through or after the problem zone?
3. Are there MWD / LWD requirements?
4. Can the section be drilled in 2 runs, 1st conventionally, then with the liner?
5. What type of bending stress will be applied to the casing string whilst it is being rotated?
6. How sensitive is the liner standoff / quality of cement bond required for Zinal isolation when cementing after drilling?
with this kind of detail - even if only high level it is quite quick to make an initial assessment for Level 2 or Level 4 CwD equipment & then move on from there.
it is, however, not a ‘post DWOP’ type decision as there should be sufficient time for proper well design type activities before deploying this type of technology. Primarily because it is the type of thing that either goes very right or very wrong....very quickly.
Happy to discuss more.
Total Posts: 89
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: 403
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: 360
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
Jump to top of the page