RU1819974C - Dampener of longitudinal vibrations of drill string - Google Patents

Abstract

Usage: to damp vibrations and shock loads at the bottom of the drill string. SUMMARY OF THE INVENTION: the device comprises a housing and a shaft mounted with limited axial movement. Between the housing and the shaft there is an elastic assembly consisting of alternating elastic and metal disks. The end surfaces of the elastic disks are corrugated. The frequency of the corrugations and the height of the corrugations of adjacent discs are different, which provides damping of vibrations of a wide frequency range. 1 ill.

Description

The invention relates to the field of drilling oil and gas wells, and in particular to downhole drilling equipment for damping vibrations and shock loads at the bottom of a drill string.

The aim of the invention is to increase the efficiency and selectivity of damping high-amplitude low-frequency vibrations of the bottom of the drill string under forced regimes of well flow.

The drawing shows a damper of longitudinal vibrations in section.

The longitudinal vibration damper comprises a housing 1 and a shaft 2, between which a movable; for example, a key (alternatively, Schlitz) connection with a key 3 and a set of elastic elastic ring elements 4 with intermediate ring disks 5. Elements 4 are made of an elastic material, the rigidity of which ensures the elastic nature of their deformation under load, at least 2, 3 ... 3 times the load on the bit. At both ends, the elastic elements 4 have corrugated surfaces, and the geometrical dimensions of the corrugations (both in height and frequency of placement) on the different elements 4 and the length of the generatrix of one such element are different from each other. Preliminary deformation of the elements 4 is provided by threaded bushings 6.

The absorber of longitudinal vibrations works as follows.

When the shaft 2 is pressed against the housing 1 by alternating loads, the energy of the latter is balanced by the work of the elastic deformation forces and the energy dissipated by the internal friction forces in the material of the elastic damping elements 4. Moreover, the execution of the end surfaces of the elements 4 is corrugated, as C increased

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The increase in their number allows one to increase the degree of dispersion and, accordingly, the degree of damping of the vibrational energy under the appropriate conditions for well boreing, with small amplitudes and apertures.

By selecting the shape and geometric parameters of the corrugated surfaces, the frequency of placement of the corrugations, as well as the number of elements 4, the required degree of damping is selected depending on the frequency and amplitude of the variable disturbing load.

Periodic alternation of the height of the corrugations along the length of the generatrix of one element 4 makes it possible to provide stiffly different stiffnesses of these elements when damping low-amplitude tooth vibrations of the bit and high-amplitude soil from bumps of the bottom or relaxation from the bottom of the string against the borehole wall in the process of deepening the bit into the rock. Thus, the entry into operation of only high corrugations of millions of high and low at the same time ensures the selectivity of damping by the amplitude of vibration displacement.

Claims (1)

Under real conditions of drilling, the axial load on as the bit deepens in the rock periodically decreases so time, and then it is restored by unloading the ESP; ZHSA columns with topmoch winch. Correspondingly, the bit rotation frequency and, consequently, the amplitude of the forced soil vibrations (occurring during the multi-cone execution of the bits), which must be damped, periodically change. Therefore, using a set of combinations of geometric parameters of corrugated surfaces on various elastic-damping elements 4, it is possible to increase the damping efficiency for the entire required vibration spectrum, and not just for its individual sections, as in known devices. The claims A damper for longitudinal vibrations of the drill string, including a housing and a shaft mounted with a possibility of limited axial movement, having a torque transmission unit located in the cavity between the body and the shaft and an elastic unit, characterized in that that, in order to increase the reliability of operation due to damping of vibrations during forced well drilling conditions, the elastic unit is made in the form of a package of ring plates of elastic material alternating with metal ring disks, and the end surfaces of the ring plates of elastic material / o are corrugated with different frequencies the location and height of the corrugations of adjacent plates.