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Flush Casing Running
29 April 2018

Dear All,

We are in serious doubt and have no experience to run the flush connections for the 30” and 24” casing strings mentioned below

1) 30” 234.290 ppf X-56XLF connection or similar

    30" casing setting depth - 2365ft

2) 24” 186.2 ppf L-80 to  XLF connection or similar casing depth - surface to 2910ft.

    24” 201.09 ppf. L-80 to  XLF connection or similar casing setting depth -2910ft - 8235ft.

Flush casing selection is to improve the clearance available. 

Well will be drilled with Surface BOP - Surface wellheads and MLS at sea bed

Water depth is @80ft with 2 million Lbs. Jack up Rig.


1) Appreciate if anyone can share the Best practice to deal with this arrangement

2) Is running Flush casing at these depths with these PPF advisable ? Yes / NO - Kindly explain why- Advantages / disadvantages

3)Is the hanging weight of the flush casing at rotary table is an important concern as compared to rotary table capacity. What could be the special casing handling equipment to be ordered

4) Several Casing Manufactures do manufacture these large diameter Flush casing and is available in the market so does that mean it is used world wide and is quite routine operation to run flush casing at depths @ 2365ft for 30"casing & and @ 8235ft for 24" casing ?     


Best regards,



4 answer(s)
Les Sinclair
Franks International
Total Posts: 2
Join Date: 10/11/15

Hi Hari,


Frank’s do have the capabilities to run the casing strings in question.

From our quick calculations based on seawater, the weight of the 30” would be 238t buoyed and the 24” string would be 692t buoyed. The weight is not an issue for us as we have ran strings in the past much heavier.

As it’s an XL Systems connection, NOV should provide you with a load ring and / or clamp to enable the picking up of a single joint from the horizontal to the vertical. From that point on in the operation we would have the tools to run the string.


We would propose to use our 1000t hydraulic extended range slip type spider and elevator for supporting the strings. As the connections take roughly three turns to make we would suggest power tongs being the most efficient way to perform this operation. We have power tongs suitable for 30” & 24” with power outputs of 140k ft lbs & 90k ft lbs respectively. We could also perform most of the tong operations remotely (No operator at the actual power tong).

The only thing we would need to calculate is the slip crush limits of the casing in question.


The logistics of such an operation would be extensively linked with what region this job would be performed in and the start date of the job as these tools are in our specialist equipment portfolio.


Feel free to contact us for further discussions. – Blackhawk Regional BD Manager – Operations coordinator

Total Posts: 20
Join Date: 03/07/12

Hi Lawrol and Hstapl,

The casing depths are correct for 30" casing

24" casing- 24" casing is a combination string to reduce the weight in Air & optimize the burst & collapse rating. that's why using 186.2 & 201.09ppf.

185/8" is the next string and it will pass the 24" casing already checked .

Also I understand VDL based on below mentioned situation needs to be addressed

1) well drilled to 8235ft.

2) Rig with Mud chemicals & Cement chemicals

4) all the casing joints onboard,

5) drill string stands in the derrick

Further some more question :

What is the worldwide policy about:

the Casing string weight in Air or is it Buoyant casing weight of the that should be considered for calculating the Maximum Hook load.

Does Rotary table static load capacity should be same as Derrick load capacity Or it should be more, since running Inner string for cementation.

In the worst case if casing is stuck close to its bottom depth, it certainly losses its Buoyancy and if the need is to free the casing string then The Overpull will be Casing weight in Air plus the Margin of Overpull.

So, my question is How do we decide the Rig derrick/crown block capacity?

Should it be based on heaviest casing string Weight in Air

or it should be based on Buoyant casing weight??




Consultant ( sort of retired but keeping in touch )
Total Posts: 34
Join Date: 27/03/11
Hari hi, 
the slip type casing tools, spider and elevator, tools you need are available, either rental or via a casing running company. However depending on location may have to be shipped in, so planning, logistics are crucial. Ensure tools have all the certs and data book with load test certificate. Dressed with all correct inserts ! Also you will need a back up set for each size.
Should be no issue with hook load provided correct tools used.
Static load on rotary table can be spread further over rig foor ( main beams ) by use of steel plates or a I beam frame. Your in house structureal engineers can check and calculate this.
Planning, procedure etc must be all worked out in advance and don't rush the job. !
regards Howard
Total Posts: 2
Join Date: 24/02/18
I have to ask you if your depths are correct. The lengths of this large casing are definitely on the more extreme end of the spectrum but given the weight of the 24” it may be correct.
have you also considered the drift ID of the 24” - can you get the next string through it, 20 or 18-3/4”??
there should not be any issues with the XLF connection, however it is a very large piece of pipe & you need to engage the casing running company early for their best practices.
You should also review the VDL for having that length & weight on deck vs the Derrick loads when drilling & preparing to POOH.
double check the handling equipment ratings for this size pipe too, 2mln lbs is no good if the elevators can only pick up 500mt
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