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Running an ESP completion with Y-tool through a whipstock?
02 December 2013
Hi all,

We are planning to run an ESP completion with a Y-tool on one of our offshore wells. The well will be sidetracked and reservoir will be drilled with 8½ 

The Service company which supplies the ESP and y-tool is afraid that the complete assembly will not pass through the installed whipstock. The given DLS over the whipstock is 10 degrees.

Other information:
- Y-tool OD: 8.05"
- ESP OD: 5.62"
- By-pass tubing size: 2⅞"
- Length complete assembly: 35m Max.
- 9⅝" 47# Casing installed across the whipstock (ID: 8.681", Drift: 8.525")
- The BHA which will drill the reservoir (8½) has 8¼" Stabilizers at 8, 21 and 30m above the bit.

Does anybody have any experience with this? 

Kind regards,

7 answer(s)
Managing Director (
Relentless Pursuit Of Perfection Ltd.
Total Posts: 413
Join Date: 10/01/05
Following up on the response in this thread about using spacers in the casing couplings, please note that we are now aware of an operator who had a problem with VAM BOLT connections also.  They are not as flush as the literature would suggest (they have photos).

When an 11¾" liner would not set and they decided to pull it out to check, it is surmised that the upper profile of the PBR (at the top of the liner) caught on the pin end (inside a casing coupling)and started the activation sequence of the liner top packer.

Just something else to be aware off.
Total Posts: 1
Join Date: 24/09/13
Good evening Bart,
Difficult to plan for this well if you have no back up in case of repetitive damage of the pump...
What about installing the pump above the window ? Even with a long intake... Sometimes it possible with a good gas handler...
A better option is probably to use a smaller pump, accepting a compromise on the flow rate.
In order to maximise your chance, why not to ask a special longer whipstock ?
Good luck !
Multilateral Specialist
Multilateral Solutions
Total Posts: 36
Join Date: 30/09/13

Hi Bart.

Once the 9⅝” has been run and is cemented and you drill out the shoe and drill the 8"” section it would be interesting if your drilling BHA has the capability on the way out of the hole to log over the whipstock area to confirm the actual DLS over the whip area.

At this point however it´s too late to do anything about it but it´s all good learning´s for the future operations.


Well Engineer
Oranje-Nassau Energie
Total Posts: 2
Join Date: 02/12/13
Thanks for the fast comments!

I like to clarify the sequence of events for this well because it may be a bit confusing as I wrote it down in my first comment:

- Slot recovery
- Install whipstock in 13⅜", mill window
- Drill 12¼" Section
- Run 9⅝" Casing
- Drill 8½ Section
- Install Lower completion
- Install Upper completion.

The ESP c/w Y-tool will be run through the installed 9⅝" Casing.

I've asked the service company to provide further information about their dogleg calculation and they will model the final situation with the 9⅝" Casing installed. 

We will use an XL whipstock which has a longer ramp and will mill the window using new milling technlogy which wil extend the length of the window by 5 ft.

We will know whether or not it fits once the drilling BHA for the 8½ hole section goes though due to the stabilizers. Plus we will simulate the ESP / Y tool assembly during the clean out run.

I think that is all we can do. If anybody has other ideas, let me know!


Well Engineering Manager
Total Posts: 30
Join Date: 30/06/08
Hi Bart,

your directional drilling contractor can do the math on the BHA to run through the whipstock and I suspect it will technically fit.  The Y tools aren't usually that long and so the assembly will be able to go through. I'd be more concerned about pushing your ESP and associated cabling out throught the whipstock into open hole.  We've had challenges with the bands that strap the power cable to the tubing catching on things and ripping off and your whipstock exit will be an ideal spot to hang up and break.  We started running spacers in the gap between pin ends on buttress connections to reduce the number of places that bands would catch and break off.  Hole stability is another concern.  ESP's usually like a trip to surface every 1 or 2 years and that can be a long time for the open hole to maintain stability.

Multilateral Specialist
Multilateral Solutions
Total Posts: 36
Join Date: 30/09/13


I´m assuming the 10deg/30m DLS has been quoted to you from the whipstock supplier.  However as they will also tell you the whipstock is not 30m long and so the DLS is calculated in various ways making some assumptions.

I´ve had this conversation several times when constructing multilateral wells and there are other factors to take into account such as the length of the window milled, the size of the liner you run over the whipstock and how the drilling BHA behaves out in the open hole once departed from the whipstock.

The reality is that once you have milled the window and drilled the lateral section you will more than likely run a liner over the whip and out into the open hole.  This liner wants to be straight and it will at the point where it passes over the whipstock want to be straight.  This will mean that the liner will contact the upper portion of the window and the lower portion of the window and will reduce the ”œcalculated” DLS significantly.  I´ve run whipstocks with a calculated 12 degree/30m and once the liner has been run and cemented logged the liner at the whipstock and the DLS is actually less than 5degree/30m.

Sit down with your casing exit company and get them to draw out in CAD or similar the liner passed over the whipstock.  The longer the window you mill and the smaller the liner you run the less the DLS will be.

Are you constrained with only one whipstock vendor?

Ken Horne.............
Completions & Workover Manager
Total Posts: 11
Join Date: 11/02/10

The normal max DLS for running ESPs is 6 deg, and <1 deg once on depth. 

I have run a number of ESP completions, both with bypass tubing and (dual) podded pumps, but never with DLS of 10 deg, probably because none of the wells had been sidetracked above the ESP location depth. (Some had been sidetracked below ESP depth for geological reasons)

Sorry I have not been more positive, but it will be extremely interesting to hear if you have success, although that is usually measured with the longevity of the ESP installation, which may be problematic!

All the best,

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