Method for preventing drill column from generating torsional resonance and flexible torque shock absorber

Abstract

The invention discloses a method for preventing a drill column from generating torsional resonance and a flexible torque shock absorber. According to the flexible torque shock absorber, more than two flexible torque transmission short joints are arranged between an upper driving connector and a lower driving shaft in a cylinder, the two end faces of each flexible torque transmission short joint are provided with sinusoidal-wave-shaped meshing teeth, every two adjacent flexible torque transmission short joints are mutually meshed together through the corresponding sinusoidal-wave-shaped meshing teeth to transmit torque, and elastic elements matched with the sinusoidal-wave-shaped meshing teeth are arranged between the meshing faces of every two adjacent sinusoidal-wave-shaped meshing teeth. According to the flexible torque shock absorber, torque shock loads generated on the drill column are buffered step by step through the flexible torque transmission short joints; meanwhile, torque peak values are dispersed and decreased through the elastic elements among the flexible torque transmission short joints, so that the severe torque shock loads are decreased until the torque shock loads disappear; therefore, the phenomenon that the drill column generates torsional resonance is avoided, the working stability of the drill column is improved, the drilling speed is increased, the well bore quality is improved, and the drilling cost is reduced.

Description

technical field [0001] The invention relates to a method for preventing torsional resonance of a drill string and a flexible torque shock absorber, belonging to the technical field of drilling tools. Background technique [0002] In the drilling process of oil, natural gas and geological exploration, in order to achieve the predetermined drilling depth, the drill bit needs to perform rotary cutting motion, and due to the change of the drill bit structure, formation, drilling pressure and other factors, the reaction torque at the bottom of the well will also change accordingly. When the rotation speed reaches a certain critical value, the drill string may experience torsional resonance. During the rotary drilling process, the lower part of the drill string bears axial pressure and torque at the same time. It can also cause the drill tool to lose its torsional stability. Excessive torque will cause another form of damage to the drill string - torsional instability. The harm c...

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Problems solved by technology

[0007] In order to solve the defect that the existing drill string cannot weaken or eliminate torque vibration while transmitting torque, the present invention provides a method for preventing torsional resonance of the drill string and a flexible torque shock absorber, thereby reducing or eliminating the vibration of the drill string during drilling. The severe torque impact load on the string can avoid the torsional resonance phenomenon of the drill string, improve the working stability of the drill string, and then improve the drilling speed and well quality, and reduce the drilling cost

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