| 摘要 |
The invention relates to well construction and is directed at an oscillation excitation in a pipe string. According to the inventive method, an operating fluid is circulated in the pipe string. An autonomous mechanism for vibrational impact embodied in the form of an element, for instance a hollow ball having a rigid envelop and filled with gas, possessing a positive floatability, covering from 0.85 to 0.95 of a cross-sectional flow area of the pipe string and having an unrestricted degree of freedom. In the second variant, the inventive device comprises a ball support embodied in the form of a transverse beam or a crossbar rigidly connected to a spiral cylindrical spring arranged inside a tube under the ball with the aid of an easy-push fit. The spring force is selected with respect to a calculated axleload dependence on the mass of the ball and on flow strength with a basic flow rate of the operating fluid. A lateral oscillation is actuated simultaneously with a displacement of the mechanism for vibrational impact inside the pipe string. A direction of displacement of the mechanism for vibrational impact, verboten frequency and amplitude, and a time of action of the vibrational impact in a determined part of the pipe string are fixed with respect to the flow rate of the operating fluid. The speed of the displacement of the mechanism for vibrational impact is fixed with respect to the basic flow rate which is defined at zero speed. When the flow rate of the operating fluid exceeds the basic flow rate, the mechanism for vibrational impact is displaced towards the bottom of the well and when flow rate of the operating fluid decreases with respect to the basic flow rate, the mechanism for vibrational impact is displaced towards the well cellar. The invention reduces a friction force during displacement inside the well, precludes sticking and performs vibration impact on the fluid medium filling the well.
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