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Whipstock thru 18-5/8"
11 August 2008
Does anyone have any experience or know of any operators who have
sidetracked thru 18-5/8" casing using a whipstock?

If it's your personal experience, then please can you indicate how
successful you were, or otherwise, and any lessons / best practice.

If it's second hand, then please could you point me in the right
direction to get more information ..

Cheers - Paul
7 answer(s)
Offshore Piling
Total Posts: 9
Join Date: 26/01/15
Dependent on structure / well configuration &  water depth,  has Conductor Whipstock Slot  recovery been considered ? If location conditions are amenable to this method, Above or Submudline (open hole) Driven Conductor Replacement operations could be worth considering. These Whipstocks range in size to suit casing from 20" to 30" .  
Managing Director (
Relentless Pursuit Of Perfection Ltd.
Total Posts: 416
Join Date: 10/01/05
Dear colleagues,

Ten years on from this original question (go to Discussion 'Whipstock through 18⅝" Casing' for the responses at the time) and here's a supplementary question.

At a recent Slot Recovery on Paper (held in Aberdeen), the last resort contingency of an 18⅝" cased hole whipstock was discussed.  There are no spare slots, so slot recovery is the only (current) option.

The original 18⅝" cement job was plagued by losses, so the conditon of the cement bond is uncertain.  In the event that it's necessary to go that way, it's planned to run a CBL.

Our questions are:
  1. What experience do you have with milling windows in uncemennted / poorly-cemented annuli?
  2. What experience do you have with running/pulling drilling assemblies and casing strings through windows milled under such conditions?
  3. What experience do you have with such large size whipstocks?
  4. What other advice/ideas do you have?
Many thanks

Drilling Specialist/Well Engineer/Training Consultant
Kingdom Drilling
Total Posts: 362
Join Date: 10/01/05
Hi Paul,

2 conducted in Uk and 25 in Norway

Source: one of the Uk's drilling services and fishing companies.

Peter Aird,
Note from moderator (Dave Taylor) : we are trying to establish who
the 2 are in the UK also as well as those in Norway other than
Drilling Analysis Engineer
Total Posts: 1
Join Date: 17/03/08
Hi there,

Further to Eric Ruyter's response, and on behalf of Tore Weltzin,
please find attached a summary of
recent StatoilHydro experience.

We hope it helps and look forward to hearing of other people's

Best wishes

Harish Pillai ..
Drilling Analysis Engineer, Subsurface Support Centre,
Subsurface Technology, Drilling Technology

Documents uploaded by user:
Total Posts: 2
Join Date: 26/03/08

We do this on a regular basis on for instance Troll (Offshore North
Sea from floaters).

xxxxxxx is our Whipstock expert, otherwise you may expect a
contribution from Tore Weltzin who is our lead drilling enginner on
Troll .. see Note

Erik Ruyter
Multilateral and Expandable Technology Group

Note from forum moderator .. rather than post people's email
addresses and names on the site we have decided to invite these
experts to join the forum. That way the discussion will remain on
the forum. The whipstock expert will return to the office on the

Managing Director (
Relentless Pursuit Of Perfection Ltd.
Total Posts: 416
Join Date: 10/01/05
Hi Jim

Thanks for such a prompt response. Perhaps after you've briefed
Paul you might be able to post a summary of your discussion for the
wider benefit of the SPREAD community.

Best wishes
Dave Taylor
UK Operations Manager (Retired)
Total Posts: 2
Join Date: 21/03/08

Smith Services have done a number of successful exits through 18
both here in the UK (2) and in Norway (+25) Please give me a call
xxxxxxxxxx if you wish to discuss further.

Jim Ford
Note from moderator:
We have removed the contact number since we prefer that all
communication goes via the forum so that as many people as possible
can benefit
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