RU2398954C1 - Spherical circular preventer - Google Patents

Abstract

FIELD: gas-and-oil industry.

SUBSTANCE: preventer consists of case with central orifice and cavity with piston therein, of cover with central orifice and spherical cavity with compactor therein, of faceplate positioned between case and cover, and of compactor position indicator made in form of rod of cylinder shape. T-groove is cut on a power end of the piston; the groove is movably joined with a head made on an upper part of the compactor position indicator. Contact surface of the cover and faceplate are conic. A packing ring sealing the zone of contact of faceplate and cover ends is installed in the groove made on the upper end of the faceplate. Collars for sealing the piston in the cavity of the case and faceplate are equipped with wipers. The disclosed here invention facilitates evaluating run of the compactor and its wear; vipers prevent untimely wear of collars at piston travel.

EFFECT: increased service life and reliability of preventer operation.

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Description

The invention relates to equipment for sealing the mouth of oil and gas wells during their construction, development and repair in order to ensure safety, prevention and elimination of oil and gas manifestations, protection of the subsoil and the environment.

The well-known “Preventor universal spherical” ПУС-180 × 35 produced by LLC “Plant Spetsburtehnika” (see website: www.specburtehnika.com/ustroystvo-preventora and Appendix 1 “Device preventer.” Printout from the site of LLC Plant Spetsburtehnika) containing:

- a housing with a Central hole and a cavity in which the piston is installed,

- a cover with a central hole, a spherical cavity and an o-ring,

- a faceplate placed between the body, the cover and the piston,

- cuffs for sealing the piston in the body cavity and faceplate,

- a sealant installed in the spherical cavity of the lid,

- hydraulic channels for connecting the body cavities with a source of hydraulic pressure.

A disadvantage of the known preventer is the inability to determine the course of the seal and its wear, which contradicts the safety requirements (GOST 12.2.115-86, p.1.2.2.). This is due to the fact that preventers of this type provide for the possibility of pacing and cranking operations with the seal closed, which leads to wear of the latter and, consequently, to increased piston stroke. At a certain limit value, the wear of the piston seal will not be enough to close the seal and seal the mouth, which can lead to an open fountain. Therefore, the absence of a pointer in the known preventer that provides control of the position and magnitude of the piston stroke reduces the safety of its operation.

The well-known "Preventor of the ring PU2-350 × 35" design of JSC VZBT, Volgograd (Abubakirov V.F. and others. "Drilling equipment, blowout preventer and wellhead", Handbook. V. 1. Moscow: IRC LLC Gazprom ”, 2007, chapter 8, section 8.3.2., Pp. 499-500), containing:

- a housing with a Central hole and a cavity in which the plunger is installed,

- a cover with a central hole and a spherical cavity in which the seal is installed;

- faceplate located between the body and the cover;

- cuffs for sealing the piston in the body cavity and faceplate,

- hydraulic channels for connecting the body cavity with a source of hydraulic pressure,

- the seal position indicator, made in the form of a rod of cylindrical shape and rigidly connected by a threaded connection to the piston,

- while on the end protrusions of the faceplate and cover are made cylindrical surfaces in contact with each other,

- moreover, a groove is made on the cylindrical surface of the end protrusion, in which the sealing ring is installed.

A disadvantage of the known preventer is the technological complexity of manufacturing and assembly. This is due to the following design features:

- a rigid connection in the form of a threaded connection of the plunger with the pointer and its movement in the high-pressure cavity under the plunger, which requires sealing of the pointer in the housing opening. All this implies a high accuracy of alignment of the housing opening with the threaded hole in the plunger, where the pointer is mounted. To achieve this result, joint processing of the housing and the plunger is necessary, which is technologically difficult and time-consuming. In addition, after joint processing, these parts lose their interchangeability, since their replacement is unacceptable, for example, during repair, since the alignment of the holes will be violated. In addition, the rigid connection between the pointer and the plunger accelerates the wear of the seal at the location of the pointer in the housing, which is associated with the possibility of turning the plunger in the latter during pacing and turning the pipes with the seal closed;

- the cylindrical shape of the contacting surfaces of the faceplate and the cover, which makes increased demands on the accuracy and purity of processing and the size of the gap between the contacting surfaces, and also increases the complexity of assembly and repair;

- the absence of wipers protecting the cuffs for sealing the piston in the body cavity and faceplate, which accelerates their wear and reduces the overhaul period.

The combination of these circumstances increases the complexity of manufacturing and assembling a well-known preventer, reduces the overhaul period, reduces the reliability and safety of its operation.

The objective of the invention is to provide a technical solution to the preventer, providing increased reliability.

To ensure this technical result in a known preventer containing

- a housing with a Central hole and a cavity in which the piston is installed,

- a cover with a central hole and a spherical cavity in which the seal is installed;

- faceplate located between the body and the cover;

- cuffs for sealing the piston in the body cavity and faceplate,

- hydraulic channels for connecting the body cavity with a source of hydraulic pressure,

- pointer position of the seal, made in the form of a rod of cylindrical shape, connected to the piston;

- contacting the ends of the faceplate and cover;

- and an o-ring that seals the contact area of the ends of the faceplate and cover,

According to the invention

- at the lower end of the piston is made an annular T-shaped groove,

- to which the head made on top of the pointer is movably connected,

- the contact surface of the cover and the faceplate is made conical,

- the o-ring is installed in the groove made on the upper end of the faceplate,

- and the cuffs that seal the piston relative to the cavity of the housing and the faceplate are additionally equipped with wipers.

The invention is illustrated by drawings, where figure 1 shows a longitudinal section of a preventer in the open position of the seal; figure 2 is a longitudinal section of the preventer in the closed position on the pipe string.

The preventer comprises a housing 1 (Fig. 1) with a central passage bore 2 for passing pipes 3, a cylindrical cavity 4 in which a piston 5 with a T-shaped annular groove 6 is placed, and hydraulic channels 7 and 8 for supplying or relieving hydraulic pressure. When installing the piston 5 in the cavity of the housing 4, a T-shaped annular groove 6 is placed above the hydraulic channel 7. On the housing 1 there is a cover 9 with a central hole 10, which is attached to the housing 1 by pins 11 and nuts 12. A protrusion 13 is made in the lower part of the cover 9. A seal 15 is placed in the spherical cavity 14 of the cover 9. A faceplate 16 is located between the housing 1, the piston 5 and the cover 9, having a cavity 17 in the upper part. A seal position indicator 19 is installed in the holes 18 of the housing 1, which has a cylindrical protrusion 20 in the upper part, size Sealed in a T-shaped annular groove 6 of the piston 5. The cover 9 and the faceplate 16 are sealed relative to each other by a seal 21 located between the protrusion 13 and the cavity 17. To seal the piston 5, cups 22 with a wiper 23 are installed in the faceplate 16, and for sealing in the housing 1 - cuffs 24 with the wiper 25. The cuffs 26 provide sealing of the position indicator of the seal 19 relative to the housing 1. The position indicator of the seal 19 is located in the casing 27, in which there are windows 28 for controlling its movement. A risk 29 is applied to the outer surface of the casing 27, which determines the position of the end face 30 of the seal position indicator 19 with the maximum allowable wear on the working edge of the seal 15.

The preventer works as follows.

When conducting hoisting operations at the wellhead, the pipe string 3 with the tool is lowered through the central hole 10 of the cover 9, the seal 15 and the central hole 2 of the housing 1. The preventer is open, and the seal 15 is through and is in an undeformed state.

To seal the wellhead, hydraulic fluid is fed into the hydraulic channel 7 of the preventer body 1 and then into the T-shaped annular groove 6 to create pressure under the piston 5. The T-shaped annular groove 6, in addition to its functional purpose, creates a cavity for uniform initial exposure to hydraulic fluid on the piston 5 to avoid distortions. Under the action of fluid pressure, the piston 5 (figure 2) rises up and moves the seal 15 along the spherical cavity 14 of the cover 9 of the preventer. The seal 15 when moving covers a deflated pipe string 3 due to the narrowing of the spherical cavity 14 of the cover 9 and seals the wellhead. The seal position indicator 19 moves with the piston 5, and therefore, behind the seal 15 signals an increase in the stroke of the piston 5 that occurs when the working edge of the seal 15 is worn and allows it to be estimated by comparing the position of the end face 30 of the seal position indicator 19 with respect to risks 29. In the case of when during the course of the piston 5, the end face 30 of the seal position indicator 19 coincides with the notch 29 (FIG. 2), which means the final wear of the working edge of the seal 15, it must be replaced.

To replace the seal 15 (Fig. 1), the cover 9 is dismantled. The conical surfaces of the protrusion 13 of the cover 9, the cavity 17 of the faceplate 16 and the sealing element 21 located on the flat bottom of the cavity 17 facilitate dismantling, since they do not create friction when moving relative to each other, and installation, since they do not require an additional exact hit when installing the cover 9 after replacing the seal 15.

If it is necessary to open the preventer, the hydraulic fluid is supplied to the hydraulic channel 8, the piston 5 lowers under pressure, the seal 15 returns to its original position under the action of the elastic properties of the material and releases the pipe string 3 (Fig. 1).

When the preventer is working, liquid with abrasive inclusions is pumped through the central hole 2 of the housing 1. The fluid interacts with the cuffs 22 and 24, causing them to wear when moving the piston 5. To protect the cuffs 22 and 24, the wiper 23 and 25 are installed in the faceplate 16 and the housing 1, made of wear-resistant material. Wipers 23 and 25 do not allow abrasive particles to enter the friction surface of cuffs 22 and 24, extend their service life and increase the reliability of the preventer (by reducing the likelihood of failure due to loss of control tightness).

Claims (1)

A spherical annular preventer containing a housing with a central bore and a cavity in which the piston is mounted, a cover with a central bore and a spherical cavity in which a seal is installed, a faceplate placed between the body and the cover, cuffs for sealing the piston in the body cavity and faceplate, hydraulic channels for communication of the body cavity with the source of hydraulic pressure, the seal position indicator, made in the form of a rod of cylindrical shape, connected to the piston in contact with each other the ends of the faceplate and the cover, and an o-ring that seals the contact area of the ends of the faceplate and the cover, characterized in that an annular T-groove is made on the lower end of the piston, to which the head made on the upper part of the pointer is movably connected, the contact surface of the cover and the faceplate is made conical, the o-ring is installed in the groove made on the upper end of the faceplate, and the cuffs that seal the piston relative to the cavity of the body and faceplate are additionally equipped with wipers.

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