mandrel casing hanger minimum tong space

[yudhichen]

dear folks,

Is there anyone can share me some api standard/any standard that mention minimum tong space especially for mandrel casing hanger (any size)?
i look at how people use power tong at rig as they need some space for static/rotating tong (lug jaw) to grip the hanger.
as far as my concern, if the tong space was too short, it might crush the thread on casing hanger (from field perspective).
simply say, i know longer is better. with the trade-off in material cost

i look around any api standard related both power tong (api 7k) & other api related (api 5ct & stuff) to determine the minimum tong space but i get nothing mention exact dimension.

from power tong information that i understand so far, it seems every tong manufacturer design it with their own experience w/o relying on some standard for whats minimum tong space needed to fit in their lug jaw for certain casing (eg. 13-3/8, 9-5/8, 7, etc)

from casing standard, the common practice that i could think so far is 1/2 x coupling length. but i bet this dimension will get me various number once i deal with many kind of thread with their coupling length recommendation, while power tong design didnt rely on thread type (only by casing size, i suppose)

any idea?

 

[redpicker]

I think the fact that API doesn't list a minimum dimension is evidence that the answer is "it depends...".

As glib as that sounds, it is probably the best answer you will find, even if you talk to people who have been in the business for 30-40 years.

It depends on the amount of torque you are applying, since the amount of torque affects the compressive force the tongs will put on the tool.

It depends on how long the internal threads are; you don't want to deform the roundness of the threads, even elastically, since this will increase the torque needed for the proper make-up.

Finally, it depends on the design of the actual tongs you are using. Some designs require more gripping area than others.

You may find some "rules of thumb" that will work, but I'd bet you'd find these are not all-encompassing. One such rule is 6 inches greater that the length of the internal threads. Whether or not this will work for your application, I cannot say.

rp

 

[yudhichen]

hi redpicker, thanx for your reply.

so, by rule of thumb,the minimum is 6". noted.

i'm thinking how field guy manage if for some reason they need to make-up connection with short tonging space casing hanger.
if i'm not mistaken, i saw some very old casing hanger design didn't have tonging space feature.
i wonder how people manage to make it up.

any idea folks?

 

[calimechengr]

if i'm not mistaken, i saw some very old casing hanger design didn't have tonging space feature.
i wonder how people manage to make it up.

any idea folks?

For some designs, there is a place on the body of the casing/tubing hanger where rig tongs can be applied. Ideally, this is in a non-sealing area. I have seen this in a lot of older designs. Another way is to thread a pup-joint into the hanger before shipping to location. Machine tongs are operated in a more controlled environment and can ensure critical areas are not damaged.

As for minimum tong length (if you choose to include), 6" or 1/2 of the coupling length are both acceptable rule of thumbs. I have spoken to some premium thread designers who do specify a minimum length for the connections. In these cases, the thread's functionality depends on the rigidity in the collar.

 

[johnchrc]

The actual gripping portion is 6" or less from my experience.

I assume you care about the length between the turning jaws and the back up at the lower end and the space between them.

That varies but I would guess 2' for most I have seen on drilling rigs. So 2' between 6" jaws. That is why part of why you see make-up pups on accessory equipment.

If you really need dimensions, call a supplier and get with tech services and go from there. If you leave 6" to grip, they will be able to make-up your tool. You also need to think about potential recuts if a thread gets damaged if you really want to make sure tool won't need to be rebuilt because you did not specify exactly where to grip your tool. It will not be like tripping in drill pipe.

Good luck with your hanger.

- CJ