Rule And Application About Drill String Vibration Of Extend Reach Well

The practice indicates, the drill string vibration is inevitably. Light lateral and axis and torsion vibrations do not affect the normal work, but the resonance state has severity effect to drill string. Jumping bit, stick-slip, torsion and big swing lateral vibration not only affect drill rate but also place premiums on accident. The drill string resonance rules are analyzed through aiming at drill string serious fatigue of Extend Reach Well (ERW) in this paper. The drill string of ERW is taken as research object, the dynamic problem is brought forward during making hole, and the mechanics model about each dynamic action is established. The drill string free vibration is analyzed about straight part and horizontal part especially. The drill string lateral vibration, axial vibration and tensional vibration are analyzed respectively. The straight part must be very straight, it is very important that vibration is reduced and avoid the vibration interfere to making hole, the linear dynamic finite element method is found, the distributing rule of resonance frequency is obtained; As for ERW vibration analysed,Then lateral vibration and tensional stick-slip vibration are analyzed mostly, the result is give, the axial vibration is analyzed with finite element method through divided the drill string into many units, then the total dynamic equation is obtained, the liquid friction is considered and the mass is modified. Some complicated moths calculates is finished with VB and the result is obtained, the result shows that the calculated result is suited for the practical problem basically. The analyze of this paper is based on the practice, it can provide bases to Straight Well as well as ERW drill string dynamic problem, it is valuable in engineering.