RU2749705C1 - At-bit damping device - Google Patents

Abstract

FIELD: drilling equipment.

SUBSTANCE: invention relates to the field of drilling equipment for absorbing harmful vibrations of a bit and drill string. The at-bit damping device includes housing, a piston mounted with the possibility of sliding inside the housing. At the same time, a shaft is installed inside the housing, which is sealed from above and below with sealing rings and is fixed relative to the initial position by a spring, which is mounted around the shaft and the inner surface of the lower part of the housing, and a dilatant fluid, which is located in the lower part of the housing. The piston is made in form of an enlarged diameter of the central part of the shaft.

EFFECT: invention increases efficiency of well drilling.

1 cl, 2 dwg

Description

The invention relates to the field of drilling equipment for absorbing harmful vibrations of a bit and drill string. The invention relates to supra-bit shock absorbers and can be used in various industries, including to ensure a trouble-free well drilling process.

Known shock absorber above the bit (patent RU No. 108087, publ. 09/10/2011), including a housing in which a shaft is placed in contact with the nipple nut by means of a spline connection, inside the housing there are rows of shock-absorbing elements in the form of rectangular rings, which are separated by metal discs, and the entire package of rings and discs is secured in the body by an upper sub and a nipple nut.

The disadvantage of this design is that rubber rings, when exposed to shock loads, can lose their integrity when tightly fastened to the shaft. As a result, the shock-absorbing ability of the device will not be provided and the rigidity of the shock absorber structure will decrease.

Known drilling supra-bit shock absorber (patent SU No. 1816023, publ. 20.10.1995), including a housing located in its cavity, a stepped shaft, forming a spline cavity with the housing with its larger step, and a smaller cavity for accommodating an elastic element, and a hydraulic unloading chamber communicating with annular space.

The disadvantage of this shock absorber is a flexible wall made of a rubber membrane, which reduces the reliability of the shock absorber structure during its operation.

Known drilling supra-bit shock absorber (patent RU No. 2015294, publ. 30.06.1994), including a housing located in its cavity, a stepped shaft, forming a spline cavity with the housing with its larger step and a smaller step - a cavity for accommodating an elastic element containing installed each above the other, rows of rubber balls, alternating with metal discs fixed on the shaft and in the housing, a hydraulic discharge chamber and a flexible wall chamber, hydraulically connected to the spline chamber.

The disadvantages of the design of this device is the presence of a hydraulic unloading chamber, which is filled with drilling fluid, which negatively affects the rubber elements, and erodes the inner cavity of the shock absorber. The complexity of the design, in comparison with the proposed device, limits the field use and maintenance of the known shock absorber. The presence of holes in a smaller shaft step reduces the reliability of the shock absorber structure under shock loads in compression and torsion.

Known hydromechanical shock absorber (patent RU No. 2255197, publ. 27.06.2005), including a housing, in the lower part of which are rows of shock-absorbing elements in the form of balls, which are separated by metal rings. A piston is located at the top of the lower part of the housing, which forms a sealed hydraulic chamber with the shaft and the upper part of the housing, designed to create additional shock-absorbing capacity and filled with diesel oil, which is supplied through hydraulic flows located in the upper part of the housing.

The disadvantages of the design of this device are that all shock-absorbing elements, due to their identical stiffness properties, operate in parallel, i.e. have the ability to dampen vibrations of a narrow frequency spectrum.

Known supra-bit shock absorber (inventor's certificate SU No. 312038, publ. 08/19/1971), taken as a prototype, including a housing with a flushing channel, the upper and lower parts of which are connected by threads, a floating piston check valve having an upper sealing element, a box-section unloading sleeve and forming a cavity with the inner cylinder of the body, connected to the flushing channel by openings, and a set of elastic and metal rings, a hollow rod equipped at the bottom with a locking thread under the bit and at the top with a pusher.

The disadvantage of this shock absorber is the presence of an adapter with a flat surface in the design; when the drilling fluid moves through the pipe to the adapter, an area of hydraulic resistance arises in the chamber between the pipe and the adapter. As a result, the formation of hydraulic resistance decreases the amortization capacity of the device. Rotation of the shock absorber body from the shaft is transmitted through radial protrusions and elastic plate elements, which can quickly wear out during operation.

The technical result is the creation of a device that increases the efficiency of drilling wells, including in intervals of rock layers alternating in strength.

The technical result is achieved by the fact that a shaft is installed inside the housing, which is sealed from above and below with sealing rings and is fixed relative to the initial position by a spring, which is mounted around the shaft and the inner surface of the lower part of the housing, and a dilatant fluid, which is located in the lower part of the housing, and the piston is made in the form of an increased diameter of the central part of the shaft.

The structure of the above-bit shock absorber is illustrated by the following figures:

fig. 1 is a block diagram of a supra-bit shock absorber device;

fig. 2 is a cross-sectional view of the shock absorber above the bit, where:

1 - drill pipe;

2 - the upper part of the body;

3 - a sealing ring;

4 - spring;

5 - the lower part of the body;

6 - piston,

7 - shaft;

8 - dilatant liquid;

9 - calibrator;

10 - chisel.

The device nadbolotnogo shock absorber (Fig. 1) includes a housing consisting of two parts - the upper part of the housing 2 and the lower part of the housing 5, hermetically connected by a tapered thread. On the upper part of the housing 2, a drill string 1, made, for example, of steel, is fixed by means of a conical threaded connection. A shaft 7 is installed inside the housing, with the ability to move along the spline grooves (Fig. 2). The central part of the shaft 7 (Fig. 1) is made with an increased diameter - the piston 6. The shaft 7 is sealed from above and below by sealing rings 3 and is fixed relative to the initial position in the housing by a spring 4 mounted around the shaft 7 and the inner surface of the lower part of the housing 5, and by a dilatant liquid 8 located in the lower part of the body 5. Under the lower part of the body 5, a calibrator 9 is fixed to the shaft 7 by means of a threaded connection, to which, with the possibility of being removed through a sub (not shown in the figure), the chisel 10 is fixed.

The device works as follows. When loading the drill pipe 1, under the action of axial shock loads and vibrations on the bit 10 and lateral vibrations on the calibrator 9, transmitted to the shaft 7, the piston 6 and shaft 7 move with sliding into the upper part of the body 2 along the sealing rings 3 with simultaneous compression of the spring 4, leading to the overflow of dilatant fluid 8 into the lower part of the housing 5 through the spline cavity of the shaft 7.

The device increases the efficiency of well drilling by reducing vibrations of the drill string by deforming the spring, damping elastic waves in the dilatant fluid medium, overcoming the forces of internal friction of the working fluid involved in oscillatory motion when the shaft moves relative to the body, as well as hydraulic resistances that appear when the working fluid flows. fluid between the cavities of the shock absorber.

Claims (1)

A shock absorber above the bit, including a housing, a piston mounted with the ability to slide inside the housing, characterized in that a shaft is installed inside the housing, which is sealed from above and below with O-rings and is fixed relative to the initial position by a spring that is mounted around the shaft and the inner surface of the lower part of the housing, and dilatant liquid, which is located in the lower part of the housing, and the piston is made in the form of an increased diameter of the central part of the shaft.

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