RU2079634C1 - Preventer - Google Patents

Abstract

FIELD: mining industry, particular, drilling of wells of any purpose. SUBSTANCE: used in the preventer is forced drive of rollers by connection of reversible drive motor. EFFECT: higher reliability of sealing of wellhead and increased service life of roller sealing members. 3 dwg

Description

The invention relates to devices that seal the wellhead for all purposes with a pressure at the mouth up to 10 kg / cm ² . It is used in the process of drilling and hoisting operations of pipe columns with a diameter of 30,500 and more mm.

Known preventer, comprising a housing, covers, roller sealing elements with annular recesses on cylindrical surfaces, stepped bushings (consisting of two symmetrical half-sleeves each), axle bolts and bearing assemblies equipped with spring-loaded stops placed in the recesses of the roller sealing elements, which ensure sealing reliability wellhead [1]
Auth. testimonial. N 385.024 adopted as a prototype, its characteristic is given above.

The prototype has disadvantages:
firstly, when pulling a pipe string lubricated with a clay solution or oil products through a preventer, its slipping occurs between the roller sealing elements, which is accompanied by their uneven wear;
secondly, there is a significant difficulty in introducing the end of the pipe string into the preventer, which is associated with a violation of safety standards.

 The purpose of the invention is to increase the reliability of the preventer while increasing durability and ensuring the complete safety of drillers.

 A wide range of diameters of the columns to be sealed at wells for all purposes and the lack of quantitative data on the use of preventers of different sizes exclude the possibility of determining the size of the economic effect. However, the expected reliability and durability of the preventer may increase by two to three times; the time required to enter the column into the preventer will decrease by dozens of times with complete safety of work.

 The goal is achieved in that the adjustable rollers communicate an adjustable torque to the additional drive pinion shaft, coupled, for example, with a shaft with a continuously variable speed of rotation of the reversible hydraulic motor. The pinion shaft is mounted on bearings with the possibility of engagement in the working position with one of the stepped bushings. Moreover, a spring is built in the cavity of the pinion shaft and in the recess of the cover of the preventer, which keeps the named gear pair in the open position with the drive switched off.

 Figure 1 is a side view of a preventer planted in a thrust bearing. The left side is without a cover, with a partial vertical section of it with the “binding” of two nodes regulating the degree of sealing and the landing of the pinion shaft of the additional roller drive.

 Figure 2 is a fragment of the upper part of the preventer, which presents a kinematic diagram of the interaction of the driving pinion shaft with gear elements of the half-sleeve of one of the rollers, which simultaneously interacts with similar elements of the half-sleeve of the second roller.

 FIG. 3 is a sectional view of FIG. 2 along BB, where the pinion shaft is disengaged from the half-sleeve elements of the roller by a spring integrated in its cavity.

Design Examples
The preventer consists of a housing 1, two covers 2 with seals 3, two roller sealing elements 4, mounted on two symmetrical stepped half-sleeves 5 and axle-bolts 6. Bearing units are placed in the protrusions of the half-sleeves 5. The teeth are cut on the disks of the stepped half-sleeves using which half-bushings of both rollers are in constant engagement, providing their synchronous rotation and tightness between them. Roller sealing elements are made with annular recesses, in which recesses are horseshoe-shaped, spring-loaded in axial and radial direction by springs 8 and 9, detachable in the plane perpendicular to axes 6, stops 10. Each stop consists of two parts that are joined together according to the spike groove system. Between them are springs, which with a given force press the stops against the annular recesses of the sealing elements in the radial and axial direction relative to their axes 6.

 The stops can be made of metal or, for example, fluoroplastic. The degree of compression of the spring 8 is regulated by screws 11.

 To seal wells with columns of different diameters, it is enough to replace the gaskets 4 with supporting sleeves 12. When the column is introduced into the preventer, its axial channel from radius "R" increases to radius "R 1", and the tightness "a" provides the necessary degree of sealing of the column, and stepwise half-sleeves are pressed tightly against the seals of 3 covers 2. This ensures well sealing. When the column moves up and down, the sealing elements with supporting stepped half-sleeves rotate on bearings. The wear of the surfaces that seal the drill pipe string is compensated automatically by the pressure of the springs 8 and 9 on the stops 10.

 To increase the reliability of the prototype preventer and the uniform wear of its roller sealing elements, its layout (in addition to the items already listed from 1 to 12) includes: gear shaft 13 with teeth 14, splines 15, with a spring 16 in its cavity and a seal 17 in the cover 2. The pinion shaft 13 15 is movable in the axial direction by the amount "l" of the stroke length of the tooth 14 of the pinion shaft 13 15, is always spring-loaded towards the cover 2, and the teeth of the pinion shaft 13 15 do not interact with the teeth of the stepped half-sleeve. When you press the end of the pinion shaft, the spring 16 is compressed, the gear teeth 14 mesh with the teeth of the stepped half sleeve 5, which are always in mesh with the same teeth of the second stepped half sleeve. The splined end of the pinion shaft 13-15 is connected, for example, with the hydraulic drive shaft.

Device operation
The descent speed of the lifting column is assigned by the technological map, and the design of the preventer does not limit it.

 Prior to entering the column into the coverage area of the roller sealing elements, their hydraulic drive is turned on, which informs them of the rotational movement in a given direction with a given speed and torque. After that, the column is introduced into the support of the action of the sealing rollers, captured by them, intersealed and passes between them in a given direction, with the minimum possible friction between the interacting surfaces and with minimal wear of the roller sealing elements.

 During the entry of the column into the zone of action of the preventer and then half-sleeves 5 are moved apart on the axes 6 and are pressed against the seals 3 of the covers 2 with their disks, being sealed with them.

Claims (1)

 A preventer comprising a housing with covers and spring-loaded stops and roller sealing elements with a drive including step bushings with a toothed outer surface mounted on bearing bearings, and sealing elements, characterized in that, in order to increase the reliability of the preventer while increasing its life service, it is equipped with a gear shaft mounted on bearings with the ability to connect with the output link of the reversible drive motor and gearing with one of the stupa chatyh sleeves, wherein the gear shaft is formed with a groove and forms a housing chamber in which a compression spring is placed.

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