RU2169825C1 - Reversible mechanism of fishing tool - Google Patents

Abstract

FIELD: oil, gas and mining industries. SUBSTANCE: invention is designed to liquidate emergencies in holes. It namely refers to gear changing direction of rotation of fishing tool. Reversible mechanism includes driving shaft, anchor and planetary reduction gear having body, satellites. Space housing compensator mounted for axial movement is located in upper part of planetary reduction gear, on location surface with anchor. External surface of lower part of body of reduction gear has holes plugged on one side. On other side these holes are connected to oil space located in central part of body. Satellites are placed in oil space. Oil space and space with compensator intercommunicate. Compensator houses rings to seal surfaces of anchor and body. EFFECT: increased operational reliability of mechanism thanks to placement of compensator in planetary reduction gear which provides protection of members of reversing gear against growing hydrostatic pressure while reversible mechanism is sunk into hole. 2 dwg

Description

 The invention relates to the oil, gas and mining industries and is intended to eliminate accidents in the well, and in particular to a device for changing the direction of rotation of a fishing tool.

 Known planetary gear device for separating pipes in the well, having a housing that receives through the rotating planetary wheels a torque acting in the direction of rotation of the hollow shaft of the device (application of Germany N 3 625 898 according to class E 21 V 31/20, publ. 1988 g .).

 In the known gearbox, the torque is transmitted to two drums, which have eccentric side surfaces that are blocked by counter-legs during the rotation of the drums, which complicates the design of the device and reduces the reliability of the gearbox.

 Known reversible mechanism of the device for turning pipes in the well, made in the form of a gearbox with a drive and driven gears in the form of worm wheels and an intermediate gear in the form of a barrel-shaped worm (patent of the Russian Federation N 2 023 862 according to class E 21 B 31/00, publ. 1994)

 This reversible mechanism is reliable during operation, but is not protected from the action of hydrostatic pressure when working in the well.

 A device for turning pipes in a well is known, comprising a hollow rod, a hydraulic anchor, the body of which has the possibility of axial movement on the hollow rod, and the reversing mechanism of the device is configured to interact with the anchor body and catcher (patent of the Russian Federation N 2139407 according to class E 21 V 31/00, publ. 1999).

 In this device, the anchor and the catcher are combined into a single mounting casing, the movement conversion mechanism is made in the form of a screw-nut transmission, and the device does not have elements equalizing the hydrostatic pressure during operation in the well, which reduces reliability during operation.

 Known reversible mechanism of a fishing tool containing a drive shaft, an anchor and a planetary gear including a housing, satellites (USSR Author's Certificate N 1737100 according to class E 21 B 31/00, publ. 1992).

 This technical solution is taken as a prototype of the present invention.

 However, it has several disadvantages.

 The reverse mechanism of the prototype contains a gearbox, the planetary rows of the drive shaft of which interact with the satellites, the gearbox does not have compensators equalizing the hydrostatic pressure that occurs when the reversing mechanism is lowered into the well, which reduces the reliability of the device during operation.

 The present invention is based on the solution of the problem of improving reliability during operation.

 According to the invention, this problem is solved due to the fact that in the planetary gearbox in the housing, in its upper part, on the landing surface with an anchor, a cavity is located and a compensator is installed with the possibility of axial movement, and in the lower part, on the outer surface, there are openings, plugged on the one hand, and, on the other hand, connected to the oil cavity located in the middle part of the housing, and in which the satellites are placed, and the oil cavity and the cavity with the compensator are interconnected, while in the compensator O-rings with an anchor surface and a housing surface are provided.

 The applicant has not identified sources containing information on technical solutions identical to the present invention, which allows us to conclude that it meets the criterion of "novelty."

 Due to the implementation of the distinguishing features of the invention (in conjunction with the features indicated in the restrictive part of the formula), important new properties of the object are achieved.

 In the proposed technical solution, improving reliability by reducing hydrostatic pressure on the device when lowering it into the well is achieved due to the fact that a cavity is made in the gearbox housing and a compensator is installed in it, the cavity with the compensator is connected to the oil cavity located in the middle part of the housing; the compensator has the possibility of axial movement through the cavity, providing equalization of hydrostatic pressure during the descent of the device into the well.

 The applicant is not aware of any publications that would contain information on the influence of the distinguishing features of the invention on the achieved technical result. In this regard, according to the applicant, it can be concluded that the claimed technical solution meets the criterion of "inventive step".

 The invention is illustrated by drawings, where in FIG. 1 - general view of the reversing mechanism; in FIG. 2 is a section AA in FIG. 1 (section of a planetary gear).

 The reversing mechanism consists of a drive shaft 1, a driven shaft 2, a planetary gear 3, an anchor 4, a sub 5.

 The drive shaft 1 is made hollow with a washing cavity 6 and has a gear 7.

 The planetary gear 3 has a prefabricated housing 8 with the upper part 9, middle 10 and lower 11 and with a seating surface 12 with an anchor 4, with a seating surface 13 with a driven shaft 2 and with a ring gear 14 and satellites 15. On the landing surface with an anchor 12 in cavities 16 are made in the upper part 9 of the housing 8 and compensators 17 are installed. O-rings 18 and 19 with an anchor 4 and with the housing 9 are installed in the compensator 17. The cavity 16 is connected to the oil cavity 20, which has an opening 21 with a plug 22.

 The work of the reversing mechanism is as follows.

 The reversing mechanism with the upper end of the shaft 1 through the sub 5 is attached to the drill pipe, and a fishing tool is attached to the lower end of the driven shaft 2. The device assembled in this way is lowered into the well until it stops with emergency pipes. During the descent into the well, the pressure of the fluid on the walls of the planetary gearbox 3 increases and compresses the housing 8, which means that parts of the housing 9, 10, 11, 12 and 13 experience pressure, and the ring gear 14 experiences hydrostatic loads. Increasing hydrostatic pressure affects the compensator 17, which moves down along the axis of the cavity 16 and compresses the oil in the oil cavity 20, while the ring gear 14 does not experience hydrostatic loads and is in mineral oil. In addition, the gear joints of the satellites 15 with the gear 7 on the shaft 1 also work in mineral oil.

 To capture the emergency object, a fishing tool is attached to the lower end of the driven shaft 2, and the right drill pipes and the reversing mechanism are lowered into the well to the sub 5, the compensator 17 equalizes the increasing hydrostatic pressure as it descends. Not reaching 20-30 m to the upper end of the emergency pipe string, the descent is stopped and flushing is performed.

 When working with a tube, the mechanism is slowly lowered into the well, the compensator 17 moves slowly through the cavity 16, avoiding pressure overloads on the elements of the planetary gear 3. They capture and walk up to the maximum load capacity of the mechanism in order to extract the emergency pipes from the well entirely. If it is not possible to remove the pipes as a whole, then the axial load is reduced to 30-60 kN and the supply of flushing fluid is turned on. Due to the hydraulic resistance, the pressure in the washing cavity 6 rises and, when it is increased by at least 5 MPa, the armature 4 is inhibited.

 Rotate the fishing column to the right by 25-30 revolutions, which through the planetary gear 3 is reversed to rotate in the left direction. Torque is transmitted to the fishing tool and the captured emergency pipes are unscrewed. The supply of flushing fluid is stopped, the anchor returns to the transport position. Emergency pipes are raised at the wellhead.

 When working with a tap or a bell, the mechanism is slowly lowered into the well, the compensator 17 moves along the cavity 16, avoiding pressure overloads on the elements of the planetary gear 3. The fishing tool is put on the emergency pipe and a compressive axial load of 20-30 kN is applied. Turn on the flushing fluid. Due to the hydraulic resistance, the pressure in the washing cavity 6 rises and when it increases by at least 5 MPa, the armature 4 is braked. The fishing column is rotated 35-40 rpm to the right. The tap or bell is rotated to the left, which leads to the screwing of the fishing tool on the emergency pipe. After that, the supply of washing liquid is stopped. Further, the work is carried out in the same sequence as when working with a tube.

 The proposed device can be manufactured industrially, which is confirmed by tests of an experimental batch of reversing mechanisms with compensators installed in them, and this determines, according to the applicant, its compliance with the criterion of "industrial applicability".

 Using the claimed solution allows to increase reliability during operation, as a compensator is installed in the planetary gearbox, which protects the reverse elements from the action of increasing hydrostatic pressure when the reversing mechanism is immersed in the well.

Claims (1)

 Reversible mechanism of a fishing tool containing a drive shaft, an anchor and a planetary gearbox including a housing, satellites, characterized in that a cavity is located in the housing in its upper part on the landing surface with an anchor and a compensator is installed with the possibility of axial movement, and in the lower part on the outside the surface has openings that are plugged on one side and on the other hand connected to an oil cavity located in the middle of the housing, and in which satellites are placed, and the oil cavity and the cavity with compensator communicated with each other, while in the jack of sealing rings made with the surface of the armature and the housing surface.

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