This paper addresses important and largely overlooked challenges that exist when making up premium casing connections with a top drive and it describes how these issues can be controlled. To investigate them, tests were performed both in the Test Lab and in the field to examine the accuracy of torque measuring equipment normally associated with top drive casing make up tools (TDCM) when considering the following situations:

  • ■ Dynamic Torque – since the TDCM and the top drive are mechanically connected to the top of the casing or tubing joint during make up, their combined rotating mass represents kinetic energy. This in turn adds dynamic torque to the connection being made up when rotation comes to a sudden stop – i.e. when the connection reaches a shoulder contact.

  • ■ "Backswing" – When the applied top drive make up torque is released abruptly, torsion generated static energy stored in the joint accelerates the above mentioned masses in the breakout direction. This translates to kinetic energy which applies breakout torque or "backswing" to the connection which can be significant depending on how rapidly the top drive make up torque is released.

The test results identified these forces conclusively and also lead to the conclusion that standard top drive torque measurement systems are not capable of measuring either of them.

In this paper the author will discuss these torque situations and present the results of the tests performed. He will conclude that both of these torque anomalies do in fact exist and that, though the response time of standard top drive torque measuring systems is sufficient for general drilling operations, it will in many cases be too slow for shouldered connections. He will also conclude that without alternative torque measuring systems the final make up speed of the top drive for premium connections must be drastically reduced to avoid the possibility of damage.

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