Do We Need an Intelligent Makeup Solution for Modern Rotary Shouldered Connections?

Teodoriu, Catalin (The University of Oklahoma)

OnePetro 

Abstract

The accurate makeup of Rotary Shouldered Connections (RSC) is a critical step in optimizing the connection lifetime under complex downhole conditions. The makeup torque value of RSC depends on the friction coefficient of the assembly and the lubricant, which cannot normally be individually measured or determined, so that the API RP7G gives a recommended makeup torque based upon an assumed, yet constant, friction coefficient while a certain safety margin is considered. Therefore, the field induced stress state of the connection may differ from the connection optimum torque under reference conditions. This will lead to the following consequences: the lifetime of each connection is not maximized based on its drillstring position and the torque and axial force that can be transferred through the connection is different from the technical maximum limit.

Due to the technological development, a wide spectrum of power tongs can accommodate the increasing interest in mechanized operations at the rig floor today. The importance of a torque-turn recording was stated in many papers as a good control method of the makeup process, especially for casing running applications. However, we believe that the reliability of a drill string can be improved by using feed back of torque turn recordings. State-of-the-art devices not only allow the precise mechanized makeup of connections, but they also provide sufficient data to analyze the quality of the connection make-up. The motivation behind the research is the desire to make use of the data that is already provided for the benefit of increased lifetime of the connections and the reduction of drill string failures, especially for drilling under extreme downhole conditions like long horizontal, HPHT or deep water.

This paper presents a short overview of the state-of-the-art of current technology followed by a discussion of how technological advances can be used to improve the drill string reliability. Also, the readers are challenged to find the answer to the title question: "Do we need an Intelligent Makeup Solution for Rotary Shouldered Connections?"