Research and Application of a Performance Calibration Method for a Double Shoulder Tool Joint

Because the torsional strength of double shoulder drilling tools is higher than that of API drilling tools,it has been used extensively. But due to the lack of comprehensive calibration method for the performances of double shoulder joints,it often fails in its application. Therefore,a performance calibration method for double shoulder tool joint has been developed according to field experiences,requirements of manufacturers and relevant standards for double shoulder tools,together with the force on the tool joints. The performance calibration can be conducted through the calculation of tong lengths,matching between ID and OD of joints,make-up torque,shear strength of thread,shoulder lifting capacities,compressive strength,etc. As such,the calibration method has been used in some drilling projects of CNPC,none of the double shoulder drilling tools failed as long as the connection performance meets requirement. It is showed that the newly developed calibration technique for double shoulder tool joint can ensure its performance requirement,and provide the safe drilling tools.