Tubular Connection Integrity: A Comparison of Pipe Makeup Methods

Abstract

Tubular connection integrity is a key to short-term and long-term well integrity. The stress on the tubular and the connection, particularly in high-pressure, high-temperature wells, creates challenges for connection providers. Proper selection of makeup method is essential to achieving long-term performance of premium connections.

The tubular running process comprises the use of a tong to make up and break out connections. Over the years many different tong types have been developed, from manual tongs to fully mechanized power tongs. The torque reaction system in the tong plays an important role in providing optimum torque to the connection, which depends on how well it eliminates undesirable side forces on and bending of the connection. Side forces create high friction on the threads that can cause the measuring system to provide an incorrect torque reading, which can result in an undertorqued connection. The friction and compressive forces can also introduce thread galling problems that affect connection integrity.

To evaluate this phenomenon, laboratory tests were performed on a 5.50-in. premium connection joint using two power tongs with three different torque reaction systems (free-floating backup, integral backup, and snub line). Strain gauges and 3D-optical strain measurements were used to analyze forces and deflection acting on the connection during makeup. Results indicate higher side forces and bending on the connection when using integral backup and snub line configurations; however, the free-floating backup system reduces these forces significantly.

This paper first highlights the importance of pipe connection integrity and the consequences when it is compromised and goes on to provide a comparison of the three torque reaction systems and their effect on the connection.