Study on the Axial Tooth Shape of CRT Slips

As a convenient, efficient, secure and high working quality casing running tool, the top drive casing running tool (CRT) has been recognized by the enterprises and users of petroleum mechanism and instrument. Slips system is an important subassembly of CRT, which directly decides the reliability, security and casing surface quality while running or drilling with casing. Based on finite element method and contact mechanics, the research model of CRT's slips system has been established and the contact influence has been studied. The effects of front angle, bottom angle and teeth interval on the slips contact interface are analyzed. As a result, the optimal axial tooth form parameters are recommended. Based upon casing intensity verification, the analytical approach to determine the slips total length has been introduced under a given maximal weight of casing string.