Session: 11-01-01- Well Drilling Technology-1

Paper Number: 102439

102439 - Analytical, Numerical and Field Data Investigation for Deriving the Condition of Stick-Slip Drill String Vibration 

Drill strings transmit the rotation from the upper end to the lower end (drill bit). The friction between the drill bit and the formation sometimes causes the stick-slip vibration, in which the drill bit repeatedly sticks and slips even though the upper end rotates at a constant speed. This stick-slip type of torsional vibration in drill strings reduces drilling efficiency and sometimes damages drill bits and pipes. Many studies have been conducted on stick-slip using numerical experiments, small-scale model experiments, or field data. However, analytical investigation of the condition for occurring stick-slip has not been sufficiently studied. This study derives the occurrence condition of stick-slip with analytical, numerical, and field data investigation and discusses the method to reduce the stick-slip vibration.

 

Firstly, this study conducted an analytical study. We created the single mass-spring-damper model for the torsional vibration of the drill string. Then, we analytically solved the rotational speed of the drill bit when the upper end rotates at a constant speed. Thus, we derived the simple condition expression of stick-slip occurrence. This condition expression can be used to quantitatively consider the effect of operational and external parameters such as rotational speed and weight on bit on the stick-slip.

 

Secondly, we conducted numerical experiments using a multi-mass model to consider the distribution of mass that could not be considered in the analytical solution. We performed a sensitivity analysis of the parameters with the numerical solutions and obtained the same results as the analytical investigation with a simple-mass model.

 

Furthermore, we analyzed the field data and experimented with a numerical model to examine the actual phenomena. We acquired the actual drilling data during the drilling operation: surface drilling data and downhole data. We estimated the stick-slip with a numerical model using the surface drilling data as input and made a comparison with the downhole data, including the bit motions.

 

Finally, we discussed appropriate operations that control stick-slip based on the obtained findings.

Presenting Author: Tatsuya Kaneko Japan Agency for Marine-Earth Science and Technology

Presenting Author Biography: Tatsuya Kaneko is a postdoctoral researcher at Japan Agency for Marine-Earth Science and Technology. His research interests are in drill string dynamics and hybrid modeling.

Authors:

Tatsuya Kaneko Japan Agency for Marine-Earth Science and Technology
Tomoya Inoue Japan Agency for Marine-Earth Science and Technology
Ryota Wada The University of Tokyo
Tokihiro Katsui Kobe University
Hiroyoshi Suzuki Osaka University