Control system and method for inhibiting stick-slip vibration of drilling string based on frequency converter auxiliary feeding set rotating speed

Abstract

The invention discloses a control system and method for inhibiting stick-slip vibration of a drilling string based on a frequency converter auxiliary feeding set rotating speed. The control system includes an oil and gas well drilling string system (controlled object), a frequency converter, a control device and a man-machine interaction device. The control method adopts an algorithm of diagnosingthe stick-slip vibration of the drilling string, a controller auxiliary feeding set rotating speed control algorithm and a frequency converter embedded proportional integral control algorithm, the controller adjusts the frequency converter auxiliary feeding set rotating speed [omega]<au> and feeds the frequency converter auxiliary feeding set rotating speed [omega]<au> back to the frequency converter to form a closed-loop feedback control system, the frequency converter PLC embedded proportional integral control algorithm constitutes another closed-loop feedback control system, the two closed-loop feedback control systems are combined to realize double closed-loop feedback control of the frequency converter, and stick-slip vibration of the drilling string is further inhibited. The controlsystem and method for inhibiting the stick-slip vibration of the drilling string based on the frequency converter auxiliary feeding set rotating speed can diagnose whether the stick-slip vibration ofa downhole drilling string occurs or not, and can inhibit the stick-slip slippage vibration phenomenon of the drilling string.

Description

technical field [0001] The invention belongs to the technical field of petroleum and natural gas exploration and development, and in particular relates to a control system and method for suppressing stick-slip vibration of a drill string based on a frequency converter with an auxiliary given speed. Background technique [0002] The drilling and development of oil and natural gas are mainly completed by the drill string system. The drill string system mainly includes a drive motor controlled by a frequency converter, a gearbox, a wellhead rotary table, a drill string connected by several drill pipes, and a bottom hole assembly. Because the drill string needs to go deep into the ground several thousand meters, the moment of inertia of the bottom hole assembly is small, and the nonlinear friction exists, the drill string system is prone to stick-slip vibration of the drill string. The stick-slip vibration phenomenon of the drill string is mainly manifested in the fact that the...

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Problems solved by technology

[0006] In view of the defects or deficiencies in the above-mentioned background technology, the purpose of the present invention is to provide a control system and control method for suppressing drill string stick-slip vibration based on a frequency converter auxiliary given speed, which is used to solve the problem that the drill string stick-slip vibration cannot be diagnosed in the prior art. The problem of sliding vibration and the problem of not being able to effectively suppress the stick-slip vibration of the drill string

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