How Much Force Applied to a Rig Tong To Get The Right Torque at The Connection

One application of the rig tong is to use to make up connection. The question is asked about how to get the right torque value to the connection if you use the rig tong because you will not see the torque value on the gauge. This article will describe how to determine the correct force applied to get the correct torque value when you use the rig tong to make up the connection.

 

This formula below is used to determine force at required make up torque value.

rig-tong

Oilfield Unit

Force = Torque ÷ Length of the tong

Where;

Torque in ft-lb

Force in lb

Length of the tong in ft

Force is perpendicular to the tong length.

The illustration above demonstrates the direction of force.

Metric Unit

Force = Torque ÷ Length of the tong

Where;

Torque in N-m

Force in

Length of the tong in m

Force is perpendicular to the tong length.

Example:

Connection 4-1/2” IF – required make up torque = 30,700 ft-lb.

Tong length is 4 ft

rig-tong-example

How much pulling force do you require to achieve the required make up torque?

Force = Torque ÷ Length of the tong

Force = 30,700 ÷ 4.0

Force = 7,675 lb

Answer: 7,675 lb pulling force is applied to 4-ft tong in order to get the torque at connection at 30,700 ft-lb.

You can download the spreadsheet from the  download link.

Ref books: 

Lapeyrouse, N.J., 2002. Formulas and calculations for drilling, production and workover, Boston: Gulf Professional publishing.

Bourgoyne, A.J.T., Chenevert , M.E. & Millheim, K.K., 1986. SPE Textbook Series, Volume 2: Applied Drilling Engineering, Society of Petroleum Engineers.

Mitchell, R.F., Miska, S. & Aadny, B.S., 2011. Fundamentals of drilling engineering, Richardson, TX: Society of Petroleum Engineers.

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2 Responses to How Much Force Applied to a Rig Tong To Get The Right Torque at The Connection

  1. Jorge says:

    I’ve got several question in this regards, and first of all it needs to be very clear how the force will be applied in respect to the tong as well as the position of the rocker pins as well as the dies!
    I think the main die is applying such a great force on the pin box that make the pipe spin if loose as a consequence, therefore if the pipe does not spin anymore there will be only a force pinching the pin box and misreadings (as torque applied to the connection) could be misinterpreted.
    I would like to send a pictorial interpretation of

  2. P.ARUMUGAM says:

    very usefull calculations

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