RU2237795C2 - Preventing device - Google Patents

Abstract

FIELD: oil and gas extractive industry.

SUBSTANCE: device has body with screw-thread die sets placed in it symmetrically perpendicularly to axis of vertical channel of device, said screw-thread dies being of two dimension types with elastic compactors. Also included is control drive for each of them, which includes drive rod having threaded connection to a nut. Screw-thread dies of two dimension types are combined in screw-thread die block and placed into body of screw-thread die block having radial compactor. Screw-thread dies of two dimension types are made in contact to each other by side and horizontal surfaces of elastic compactors. In screw-thread die blocks upper screw-thread die is mounted in fixed manner in the body of screw-thread die block. Drive rod of upper screw-thread die is made hollow and connected to body of screw-thread die block with possible rotation around it. Inside drive hollow rod a drive rod for lower screw-thread die is placed, connected to it with possible rotation around it and around drive hollow rod. Common rotation axis for drive rods is placed perpendicularly to axis of vertical channel of device and may by displaced vertically for a value within limits from zero to half of diameter of recess for body of screw-thread die block.

EFFECT: reliable pressurization of compacted pipes during drilling process and wells maintenance and simplified maintenance, decreased height of device, its metal cost and lesser time needed for closing device.

3 cl, 3 dwg

Description

The invention relates to the oil and gas industry, and in particular to devices for sealing the mouth in order to prevent oil and gas occurrences and open fountains during drilling and well repair.

A known preventer (patent RU No. 2111336 C1, 6 E 21 B 33/06, publ. 20.05.98), comprising a housing, dies with seals installed therein and a drive, the dies in cross section made of cylindrical shape bounded eccentrically located relative to each other upper and lower semicircles.

A disadvantage of the known preventer is the structural and technological complexity due to the configuration of the die. In addition, this preventer provides sealing of the wellhead with only one set of dies (pipe or blind), which reduces its operational capabilities and requires, in accordance with industrial safety rules, the installation of two preventers at the wellhead - the lower with blind and the upper with pipe. Thus, the layout of wellhead blowout preventer (air defense) equipment will have a significant height dimension.

Known hydraulic driven preventer (US patent No. 5504266, IPC ⁶ E 21 B 33/06, publ. 04/09/1996), comprising a housing with a central axial hole and two tiers of horizontal cavities in which are placed dies with replaceable seals placed in grooves made in the housing of the dies, installed outside the housing coaxially to the horizontal cavities of the side pipes, in which the mechanisms for moving the dies are located, including hydraulic cylinders, threaded rods interacting with the nuts of the side pipes, seals and steering wheels manually of control.

A disadvantage of the known preventer is its considerable height due to the fact that the dies for various purposes (blind for complete overlapping of the central axial hole and pipe for sealing pipes of various sizes) are located in the side pipes arranged in tiers vertically arranged relative to the housing. Thus, the layout (air defense), located at the wellhead under the rig block of the drilling rig, having an increased overall height, requires:

- increased labor costs for the maintenance of a well-known preventer;

- increased costs for the installation of the drilling rig due to the need to lift the tower block on additional bases, as a result of which there is a deterioration in the mounting capacity of the drilling rig, in cooperation with which a well-known preventer is operated.

Known multi-locking preventer Wheat (patent RU No. 20133520 C1, IPC ⁵ E 21 B 33/06, publ. 05/30/1994), including

- a housing with a central axial hole and horizontal cavities located in the same plane,

- interchangeable base installed coaxially with the central axial hole with variable inner and outer diameters,

- combined cylindrical dies installed with the possibility of movement in horizontal cavities, containing upper and lower tiers of seals, the lower of which interact with the base and the upper ones between themselves or between themselves and the pipe being sealed,

- the mechanisms for moving the dies, including threaded rods, nuts, seals and flywheels, located in the side pipes connected to the body coaxially with the horizontal cavities.

A disadvantage of the known preventer is the significant dimensions in the horizontal plane due to the lateral nozzles evenly spaced around the housing, the radial dimension of which is further increased by the lateral nozzles with the drive mechanisms of the dies. This increases the complexity of the repair and maintenance of a well-known preventer.

In addition, if there are elements with different external diameters (several sizes of drill pipes, heavy drill pipes, a turbo-drill (screw motor), centralizers, stabilizers and chisels) in the descent (lift) assembly of the drill string, the known preventer cannot provide any hoisting operations, nor sealing of the mouth, since as the descent and ascent of the layout elements, a basement with variable internal and external diameters needs to be changed, for which the preventer must be dismantled from the mouth. Thus, the labor costs and the preparation time of the known preventer for use are increased.

A significant disadvantage of the known preventer is the low reliability due to the closed volume (“pocket”) formed in the horizontal cavity by a removable base and dies, while the height of the “pocket” is equal to the height of the replaceable base. During the drilling process, when flushing the well into this “pocket”, the solid phase of the circulating drilling fluid, sludge and foreign objects will fall out and precipitate. Therefore, when moving the dies to seal the wellhead, the tiers of seals will not be able to close either with the base or with each other, since this will be hindered by the contents of the “pocket”. The lack of access from above for regular cleaning of the “pocket” before using the preventer requires disassembling it — dismantling the side pipes with mechanisms for moving and removing the dies. This operation is quite long and requires no less than half an hour - an hour of work, which in the case of a started discharge of drilling fluid, where the time of the drilling crew’s actions is minutes or even seconds, will not ensure the efficiency of sealing the mouth and can lead to an open fountain.

The objective of the invention is to create a design that ensures the reliability of the sealing of the sealed pipes during drilling and well repair, ease of maintenance, reducing the height of the preventer, its metal consumption.

The task and technical result are achieved by the fact that in the proposed preventer, comprising a housing with sets of dies of two standard sizes with elastic seals symmetrically arranged perpendicular to the axis of the vertical channel, with a control drive for each of them, including a drive rod having a threaded connection with a nut, unlike the prototype, the dies of two sizes are combined into one die block and placed in the die block housing having a radial seal. The dies of two sizes are made in contact with each other by the lateral and horizontal surfaces of the elastic seals. In the die blocks, the upper die is fixedly mounted in the die block case, the drive rod of the upper die is hollow and is rotatably connected to the die block case relative to it. Inside the drive hollow rod there is a rod of the lower die connected with it with the possibility of rotation relative to it and the drive hollow rod. Moreover, the common axis of rotation of the drive rods is perpendicular to the axis of the vertical channel of the preventer and can be shifted vertically by an amount ranging from zero to half the diameter of the bore under the body of the die block. In addition, the set of lower dies is made with the possibility of blocking only the pipe channel that remained open after mixing the bodies of the die block, and the case of the die block has a cylindrical shape and a circular shape in cross section along the groove intended for the radial seal.

Based on the foregoing, we can conclude that this invention meets the criterion of "novelty."

Due to such a design of the drive unit of the dies and the location of the dies themselves, a higher (compared with the prototype) effect is achieved: the altitude and overall characteristics of the preventer as a whole are reduced, and the closure time of the preventer is reduced.

Figure 1 shows a General view of the preventer in the open position; figure 2 is a section of the housing of the die block with dies; figure 3 is a top view.

The preventer comprises a housing 1, in which sets of dies of two sizes 3 and 4 with interchangeable seals integrated into a die block are arranged symmetrically perpendicular to the axis of the vertical channel of the preventer. The die block is placed in the housing of the die block 2, equipped with a radial seal 5. The drive hollow stem 6 of the upper die 4 is rigidly connected to the housing of the die block 2, having a threaded part (inner and outer) and a seat for the control wheel 7. Drive rod 8 of the lower die 3 is located inside the hollow rod 6, is with it on the same axis of rotation. It is connected to the die 3 and has on the opposite side a threaded part with a seat for the control wheel 9. A nut 10 with seals is located on the drive hollow stem 6. The union nut 11 is rigidly connected by thread to the body of the preventer 1.

The drive hollow rod 6 is connected with the housing of the die block 2 with the possibility of rotation relative to the latter on the sliding bearing 12, and the drive rod 8 is connected with the lower die (deaf) 3 with the possibility of rotation relative to it on the sliding bearing 13.

In the housing of the die block 2, the upper die 4 is fixedly mounted, and the lower die 3 has the possibility of horizontal movement together with the drive rod 8 relative to the die 4 and, accordingly, the housing of the die block 2.

The housing of the die block is made in the form of a cylinder, in cross section, intended for the radial seal, represents a circle.

The device operates as follows.

Closing the preventer if there is a drill pipe or tubing in the well:

The rotation of the steering wheel 7 moves the drive hollow stem 6, interacting with a threaded connection with a nut 10, which is stationary relative to the casing of the preventer 1, moving the casing of the block 2 in the direction of the center of the well until the seal of the upper ram 4 stops in the drill pipe string. The preventer is closed.

Closing the preventer in the absence of a drill pipe or tubing in the well:

Rotating the steering wheel 7 moves the hollow rod 6, interacting with a threaded connection with a nut 10, which is stationary relative to the casing of the preventer 1 and, accordingly, moves the casing of the block 2 in the axial direction to the center of the well, to the stop of the casing of the block blocks and, respectively, the upper dies 4 friend. In this case, the drive (inner) rod 8 rotates at the same angular speed and moves the same axial distance as the hollow rod 6, and the lower die (blank) 3 remains stationary relative to the body of the die block 2.

Then, by rotation of the steering wheel 9, the drive rod 8 is moved with the lower die (blind) 3 rigidly connected to it until the dies stop against each other, or in the second pipe size. The axial movement of the drive rod 8 occurs along the internal thread of the hollow rod 6 and the outer rod 8, and the hollow rod 6 is stationary, since it is already screwed to the stop. The preventer is closed.

Since the hollow rod 6 is rigidly connected with the housing of the die block 2, the rotation of the helm 7 in the opposite direction results in the opening of the block, then by rotating the helm 9 set the lower dies to their initial position. The preventer is open.

Claims (3)

1. A preventer comprising a housing with sets of dies of two standard sizes with elastic seals placed symmetrically located perpendicular to the axis of the vertical channel of the preventer, with a control drive for each of them, including a drive rod having a threaded connection with a nut, characterized in that the dies of two sizes are combined in a die block and placed in a die block case having a radial seal, the dies of two sizes are made in contact with each other lateral and horizontal surfaces of elastic gaskets, while in the die blocks the upper die is fixedly mounted in the die block case, the drive rod of the upper die is hollow and connected to the case of the die block rotatably relative to it, inside the drive hollow rod there is a drive rod of the lower die connected to it with the possibility of rotation relative to it and the drive hollow rod, and the common axis of rotation of the drive rods is perpendicular to the axis of the vertical channel of the preventer and can be l is shifted vertically by an amount ranging from zero to half the diameter of the bore under the body of the die block. 2. The preventer according to claim 1, characterized in that the set of lower dies is made with the possibility of blocking only the pipe channel that remains open after mixing the bodies of the die block. 3. The preventer according to claim 1, characterized in that the housing of the die block has a cylindrical shape and in cross section along a groove intended for a radial seal, it is round in shape.

Images