SU1620606A1 - Blowout preventer - Google Patents

Description

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(21) 4604638/03 (22) 11.11.88 (46) 01.15.91. Bul No. 2 (75) P.Pshenichny (53) 622.245.7 (088.8) (56) USSR Author's Certificate No. 1007500. cl. Е 21 В 33/06. 1980. USSR author's certificate number 977703. class. Е 21 В 33/06. 1981

(54) PREFERENCE

(57) The invention relates to the oil and gas industry and is intended to seal the wellhead. The purpose of the invention is to increase the reliability of the preventer and the durability of the dies by eliminating their wear during drilling and lifting operations, as well as ensuring the dies are fixed to the rim

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ABOUT

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these are the positions of the sealer. The preventer includes a housing 1 in which a labyrinth sleeve 2 and a hollow shaft 7 with grooves 9 and 10 are installed. Inside the hollow shaft 7, a sealer is installed in the form of a collet mechanism consisting of a hub 17 with a latch 20 and lobe springs 18 with dies 19. Piston 21 The hydraulic actuator is connected with the sealer 16 through the hollow rod 30. When the working fluid is supplied to the cavity 24, the piston 21 is displaced. It relates to the oil and gas industry and is intended to seal the mouth of an oil and gas well.

The purpose of the invention is to increase the reliability of the preventer and the durability of the dies using a pug to prevent their wear during drilling and lifting operations, as well as to ensure that the dies are fixed in the extreme positions of the sealer.

FIG. 1 shows a preventer, longitudinal section; to the left of the axis of symmetry of the plate in the open position, to the right of the axis of symmetry - in the closed position; in fig. 2 shows section A-A in FIG. 1 on dies sealing a round drill string; in FIG. 3 is the same when sealing a square drill string.

The preventer consists of a housing 1 in which a labyrinth sleeve 2 is installed, which interacts with a worm gear 3. In the lower part of the housing there is a flange 4 on the thread, which adjusts the position of the packing follower. 5 with a spring 6, which define the gap between the labyrinth sleeve 2 and the hollow shaft 7.

The hollow shaft 7 is mounted in the housing 1 on a angular contact bearing 8 and is made with recesses 9 and 10 and a piercing channel 11 connected to the channel 12 in the housing 1 through the recess 13 in the labyrinth sleeve 2 and the recess 14 and the cavity 15 in the housing 1.

Inside the hollow shaft 7, a sealer is installed in the form of a collet mechanism 16, consisting of a hub 17 with petal springs 18, on which dies 19 are attached for pipes of circular or square cross section. In the annular recess of the hub, a retainer 20 is placed, which is acting with the recesses 9 and 10 of the hollow shaft 7 in the extreme upper and lower positions of the sealer 16.

pushes the hub 17 and petal springs 18 down, while the latter, slipping along the tapered bore of the hollow shaft 7, compresses the drill pipe with dies 19. When the working fluid is supplied to the cavity 23 to open the sealer 16c, the piston 21 moves upwards. Petal springs 18c are uncoupled with dies 19 in the resulting gap between the sealer and the hollow shaft 7. The preventer is open. 3 il.

The seal 16 is moved by means of a hydraulic actuator consisting of a piston 21, preloaded by a spring 22 and having an opening 23 and a cavity 24, connected to hydraulic control via channels 26 and 27 in the housing 1. The cavity 24 also communicates with the cavity of the well. In the housing 1 there is an annular cavity 25 and channels 28 and 29, respectively, for lubricating the friction unit between the backbone 5 and the hollow shaft 7 and draining the fluid.

The piston 21 is connected to the sealer 16 via a hollow rod 30 and a thrust bearing.

31.

The preventer works as follows.

Prior to the operation of the preventer, the gap between the labyrinth sleeve 2 and the hollow shaft 7 is adjusted using a worm gear 3, which depends on the physical properties of the borehole medium

In order to seal the wellhead in the absence of a pressure preventer under hydraulic pressure preventer, the working fluid under pressure passes through the channel 26 into the cavity 24. The piston 21 under the action of pressure and the spring 22 moves to the lower position, while the axial force

from the piston 21, through the hollow rod 30, the hub 17 and the leaf springs 18 sliding along the tapered bore of the hollow shaft 7, is transmitted to the dies 19, which press out the drill pipe.

The latch 20 is squeezed out of the recess

9 and closes with the recess 10. The preventer is closed.

When the pressure rises under the preventer, the mouth is automatically sealed. Since the cavity 24 is closed by a pipeline (not shown) communicating with the cavity of the well, then with a sudden increase in pressure, the well environment enters through the channel 26 into the cavity 24.

will act on the piston 21, moving together with the spring 22 to move it down

At the same time, the borehole environment will act on the lower end of the dies 19, trying to lift them. However, since the area of the piston 21 is much larger, it moves downwards and the dies 19 compress the drill pipe and seal the well.

Arbitrary depressurization is eliminated by the interaction of the latch 20 with the undercut 10 and the pressure of the downhole medium on the piston 21.

Sealing the wellhead is possible both when the drill string is static and when it rotates. In the latter case, the angular contact bearing 8, the hollow shaft 7, the sealer 16, the hollow rod 30 and the piston 21 rotate along with the column.

The turning of the drill string in the presence of pressure under the preventer is carried out with the dies 19 closed. Pressing the dies 19 against the faceted rod should provide only the required degree of sealing, since the torque transfer to the sealer 16 is carried out by the faces of the rod. The force of pressing the dies to the round column should provide not only the tightness, but also the necessary amount of sliding friction between them, sufficient to transfer the torque to the sealer 16.

Before turning the drill string through, the channel 12 into the cavity 15 is supplied with a liquid or gaseous medium at a pressure equal to or greater than the pressure of the borehole medium, which through the recess 14 enters the recess 13, from where one part goes through the gap between the labyrinth bushing 2 and the hollow shaft 7 , sealing it, and through the channel 28 is drained for reuse, simultaneously lubricating the friction unit between the bow 5 and the hollow shaft 2; the second part, along the gap between the labyrinth sleeve 2 and the hollow shaft, enters the annular cavity 25, and from it through the channel 29 it is drained for reuse; third

the part enters through channel 11 to lubricate the plates 19. The rotation of the column or rod through the plates 19 is transmitted to the hollow shaft 2, the hollow rod 10, with which the middle bearing ring 31 rotates and the piston 21 remains non-rotating. When turning the sealed column, the radial-thrust bearing 8 rotates with it. The hollow shaft 7, the sealer 16, the thrust bearing 31 and the piston 21.

To depressurize the wellhead, the working hydraulic fluid under pressure flows through the channel 27 into the opening cavity 23. The piston 21 is moved to the upper position by the action of pressure. The retainer 20 is squeezed out of the recess 10 and closes with the recess 9. Together with the piston 21, the sealer 16 moves upwards and the spring springs 18 and associated plates 19 are expanded in the resulting gap between it and the hollow shaft 7. The preventer is open. The arbitrary movement of the sealer 16 down is excluded by the interaction of the latch 20 with the recess 9.

Claims (1)

Claims of the invention A preventer comprising a housing with a hollow shaft disposed therein with a sealing device in the form of a collet mechanism with dies, characterized in that, in order to increase the reliability of the preventor and the durability of the dies, by eliminating their wear during drilling and tripping. as well as ensuring the fixing of the dies in the extreme positions of the sealer, it is provided with a hollow rod mounted concentrically in the housing with a piston located above the dies of the collet mechanism, the housing having a radial canal for communicating the space above the piston to the cavity well, the hollow shaft is formed with grooves, and the collet mechanism is arranged to cooperate with a hollow shaft and has tabs to be arranged in the slots of the hollow shaft in the extreme upper and lower positions of the dock. 4-q 2 Fi gz