Investigate of Different Parameters Effect on Stick-slip and Bit-bounce Interaction in Oil-well Drillstrings

Investigation of vibration in drill string is very important issue, like the other rotary machineries. Vibration is one of the effective factors on life and also performance of drillstring. The axial and torsional vibrations are common vibrations that can be noted. The major source of axial vibration caused by bit contact with bottom of well. The effect of that vibration is occurred by bit bouncing and stick-slip is the major source of torsional vibration. In this study, dynamic behavior and physical model of drill string in contact with the rock are intended. And also the parameters that have important vibrational behavior, such as rotational velocity of drill string and weight on bit, and those effects on axial and torsional vibrations are investigated. In this evaluation, the equations were obtained using Lumped Parameter Model and also the equations were solved using MATLAB software. The results show that increasing the velocity of drill string and decreasing weight on bit can be canceled torsional vibrations. Axial vibration may be removed, by avoiding critical velocity

Keywords:

Stick-slip , Bit-bounce , Vibration , Drilling