Sucker Rod Make Up: All About Displacement, or is it?

Abstract

Abstract Although sucker rod connections are more understood now than they have been in the past, they are a surprisingly complex part of sucker rod operations, and we continue to learn about them. This study aims to further understand sucker rod connection make up variables, how those variables could affect operational reliability, and how to achieve optimal make up conditions. The variables considered were connections with and without pin lube, various coupling and rod grades, and sucker rod tong capabilities. This study was performed using connection make up and break out testing and secondarily rod tong diagnostics in the field. The connection make up and break out testing was performed using specialized sucker rod make up equipment that could measure make up and break out torque, as well as circumferential displacement. All the previous measurements were taken in varying connection conditions and combinations. This data was analyzed to understand how these conditions affect make up and back off torque. Concurrently with this testing, sucker rod tong diagnostic operations (torque/hydraulic pressure measurements) were being carried out in the field to understand the torque accuracy and capability of sucker rod tongs. The connection make up and break out testing revealed that connection make up without pin thread lubrication or with proper pin thread lubrication practices both yield acceptable back off torque values. Secondarily, the back off testing confirmed that there is considerable variation in torque necessary when varying rod grade, but not coupling grade. The sucker rod tong diagnostics revealed that many rod tongs do not reach manufacturer specifications for max torque and many also have considerable torque variation that could result in improper make up.