Rotary wellhead sealer with adjustable bearing assembly

Abstract

This utility model relates to the oil industry and is used in wellhead sealing equipment for managed pressure drilling (MPD) and underbalanced drilling (UBD) with tripping operations using a rotating drill string. The technical result of this utility model is to improve the accuracy and processability of adjusting the specified bearing position in a bearing assembly relative to the rotor.The technical result is achieved in that the rotary wellhead sealer comprises a hollow housing with a vertical axial opening with a circular cross-section, in which a bearing unit is coaxially mounted, including a hollow housing of the bearing unit, a cover and bearings mounted inside the housing of the bearing unit, and a hollow rotor, wherein a thread is made on the inner side surface of the hollow housing of the bearing unit in the end zone on the side of the cover to a predetermined depth, and a mating thread is made on the outer side surface of the cover, which together ensure the mating of the inner side surface of the hollow housing of the bearing unit with the outer side surface of the cover when it is screwed / unscrewed. 2 ill.

Description

[0001] The utility model relates to the oil industry and is used in equipment for sealing the wellhead during controlled pressure drilling and underbalanced drilling with tripping operations using a rotating drill pipe string.

[0002] A wellhead rotary sealant is known (see patent RU No. 174332, IPC E21B 33 / 03, published 11.10.2017), including a stator consisting of a hollow cylindrical body, the outer surface of which in its lower part has a conical shape mating with the inner conical surface of the wellhead flange, on the outer conical surface of the stator an annular groove is made for the entry of sliders that fix the stator in the wellhead flange, a rotor with a through axial channel for passing pipes is installed inside the stator by means of a bearing unit, characterized in that the rotor consists of a rotary sleeve and a hollow rotary body connected to it in the upper part by means of a threaded connection and a retainer, in the inner channel of which a removable adjustable sealing unit is installed, having a central hole in the shape of a leading pipe and fixed in the rotary body by means of nuts,wherein the removable adjustable sealing unit is made detachable in the vertical plane of the axial channel passing through the opposite vertices of the square of the leading pipe, dividing the parts included therein in half, and consists of a metal support sector, a metal clamping sector and a sealing element located between them, made of an elastic flexible material, the parts of the removable adjustable unit are connected to each other by tie bolts passing through four axial channels of a circular cross-section, symmetrically made in all parts of the unit, nuts installed on the tie bolts adjust the compression of the sealing element until the sealing of the leading pipe is ensured, the outer side surfaces of the support sectors of the removable adjustable sealing unit have curved side surfaces mating with the curved side surfaces of the rotary housing, due to which the transmission of the torque of the leading pipe to the rotor is ensured,moreover, on the outer conical surface of the stator there are two annular grooves into which sealing rings are inserted,

[0003] A disadvantage of this well-known sealer is that the rolling bearing is secured in the stator with a retaining spring ring. According to GOST 13943-86, the width of retaining rings for sizes with a nominal diameter of 150 mm to 320 mm, suitable for this device, is 3 mm, and the groove for installing the ring is 3.4 mm. Therefore, the bearing has an initial play of at least 0.4 mm during installation, which contributes to accelerated wear and a reduced service life.

[0004] A modular rotary sealer is known (see US Patent No. 10738558, IPC E21B 33 / 08, published on 11.08.2020), comprising: a housing with an axial cylindrical bore, as well as a cylindrical bore located in the cross-section of the housing, and a hub connecting element protruding from the housing and having an opening made coaxially with the axial bore of the housing; a bearing assembly located at least partially inside the axial cylindrical bore of the housing and including a hub formed on the bearing assembly for rotationally connecting the bearing assembly to the housing; a rubber sealing assembly connected to the bearing assembly for rotating with it in order to tightly connect the bearing assembly to a drill pipe when the drill pipe is inserted through the axial cylindrical bore of the housing;a clamping assembly including two outer clamps pivotally connected to a central clamp located therebetween, wherein each of the two outer clamps and the central clamp are configured to connect a portion of a hub of a bearing assembly to a portion of a hub connector of a housing, and the two outer clamps and the central clamp as a whole extend along the perimeter of the bearing assembly to connect the hub of the bearing assembly to the hub connector of the housing; wherein the two outer clamps are connected by a closing and opening device designed to simultaneously move the outer clamps, which allows the outer clamps to be closed and opened by means of the closing and opening device for clamping and releasing the bearing assembly from the housing; and an input flange having an opening coaxial with an axial opening of the housing, removably connected to the housing by means of a plurality of clamps held in grooves through the side walls of the housing;and further including a guide plate protruding from the side wall of the housing, wherein the clamping unit includes pins that fit into grooves in the guide plate.

[0005] The well-known sealer has the following drawbacks: the housing and lower flange, while separate, are connected via a rubber sealing element, which prevents adjustment of the support bearing. As a result, axial play develops in the bearing during operation. To eliminate this play, an additional sealing element of a specific thickness must be installed (which must be selected for each specific application). These operations are quite complex technologically and cannot always ensure adequate sealing without changing the bearing's position.

[0006] A wellhead rotary sealer (prototype) is known (see patent RU No. 2798532, IPC E21B 33 / 03, published on 23.06.2023), comprising a hollow cylindrical body with a central through channel for passing pipes with process equipment, equipped with lower and upper flanges for fastening to the equipment at the wellhead and for fastening the process equipment, respectively, locking covers with a central hole for centering the string of pipes being lowered or raised, installed in the hollow cylindrical body from above and below, a rotor containing a rotor body installed in the hollow cylindrical body of the sealer, inside which a sealing cuff and elements for connecting it to the rotor body are installed, wherein the rotor is equipped with one rotation support in the form of a rolling bearing, a working hydraulic chamber in the form of an annular cavity between the body and the sealing element, filled with a working agent,a device for controlling the force of pressing the sealing cuff to the pipe, hydraulically connected to the working hydraulic chamber, and hydraulic channels, characterized in that it is provided with a movable support installed between the rotation support and the locking cover on the side of the upper flange, made in the form of a metal or composite washer, containing at least one sealing groove for installing a sealing ring and a structural element in the form of a shaped groove, or a shaped protrusion, or a hole, or a pin for interaction with a mating structural element in the form of a shaped protrusion, or a shaped groove, or a pin, or a hole, respectively, made in the locking cover and limiting the movable support from rotation around the central axis of the rotor, but not preventing the free movement of the movable support in a plane perpendicular to the central axis of the rotor during their interaction.,

[0007] The disadvantage of the known sealant is the non-adjustable installation of the cover in the housing through a thread or bayonet connection, which does not allow you to adjust the amount of compression of the thrust bearing through a movable support (the bearing is fixed with the possibility of displacement radially and up and down along the axis) and, accordingly, the axial play of the thrust bearing during assembly and due to wear during operation.

[0008] The technical result of the claimed utility model consists in increasing the accuracy and technological effectiveness of adjusting the specified position of bearings in a bearing assembly relative to the rotor.

[0009] The technical result is achieved in that the rotary wellhead sealer (RUS) contains a hollow body with a vertical axial opening with a circular cross-section, in which a bearing unit is coaxially mounted, including a hollow housing of the bearing unit, a cover and bearings installed inside the housing of the bearing unit, and a hollow rotor, wherein on the inner side surface of the hollow housing of the bearing unit in the end zone from the side of the cover a thread is made to a predetermined depth, and on the outer side surface of the cover a mating thread is made, which together ensure the mating of the inner side surface of the hollow housing of the bearing unit with the outer side surface of the cover when it is screwed / unscrewed.

[0010] The utility model is illustrated by drawings, where

[0011] Fig. 1 schematically shows a vertical axial section of the sealer,

[0012] in Fig. 2 - the design of unit A according to Fig. 1.

[0013] In the presented drawings, the elements of the claimed device are designated as follows:

[0014] 1 - Rotary wellhead sealer body

[0015] 2 - bearing housing

[0016] 3 - rotor

[0017] 4 - bearing

[0018] 5 - Rotary seals

[0019] 6 - cover

[0020] 7 - the mating section of the thread of the side surface of the bearing unit housing and the thread of the cover

[0021] 8 - lock screws.

[0022] In addition, the drawings indicate the following elements that do not affect the achievement of the claimed technical result, but provide a more complete idea of ​​the possible configurations of the device as a whole:

[0023] 8 - Locking screws

[0024] 9 - lid seal.

[0025] 10 - Drill pipe seal

[0026] 11- bearing housing seal

[0027] 12 - Bearing unit clamp

[0028] 13, 14 - side flanges.

[0029] The wellhead sealing device operates as follows.

[0030] At the factory, the bearing unit is assembled: roller radial-thrust bearings 4 are pressed onto the rotor 3, rotary seals 5 are installed in the housing 2 and cover 6, then the rotor 3 with bearings 4 is pressed into the housing 2 of the bearing unit until it stops, the cover seal 9 is installed in the housing 2 and the cover 6 is screwed into the housing 2 by a specified value of the thread mating section 7 until the required gap value (within 0.01-0.05 mm) is ensured between the cover 6 and the bearing 4. To fix it from being turned away, the cover 6 is connected to the housing 2 with lock screws 8. The cavity of the bearing unit is filled with bearing grease. A drill pipe seal 10 is attached to the lower end of the rotor 3. Seals for the bearing unit housing 11 are installed in grooves on the outer surface of the housing 2.On the test bench, the moment of free rotation of rotor 3 in housing 2 of the bearing unit is determined; if necessary, the final position of bearing 4 is adjusted by rotating cover 6 (by additionally tightening it or releasing it along section 7, having first disconnected locking screws 8).

[0031] At the wellhead, the lower flange of the rotary wellhead seal (1) is connected to the upper flange of the blowout preventer assembly (BOP). Before installing the bearing assembly in the housing (1), the drill pipe is passed through the rotor (3) and the drill pipe seal (10). The bottom hole assembly (BHA) (including the bit, motor, calibrators, telemetry system, etc.) is installed on the lower thread of the drill pipe. The BHA is passed through the central opening of the BHA housing (1), and the bearing assembly with the drill pipe is installed in the housing (1). The housing (2) of the bearing assembly is secured in the housing (1) with clamp (12).

[0032] During tripping operations, the drill pipe moves axially relative to the drill pipe seal 10, hermetically sealing the annular space between the drill string and casing from the atmosphere. When rotating, the drill pipe seal 10 rotates with the drill string. Circulating drilling fluid exits the rotary wellhead seal through flanges 12 or 13.

[0033] During operation (usually every 300-500 hours of operation), the RUG is subject to maintenance, during which the axial play of the rotor 3 and, accordingly, the bearings 4 are measured, for which the bearing unit is disconnected from the housing 1 of the RUG and intermediate control measurements of the free rotation moment of the rotor 3 are carried out. If the play value does not correspond to the specified parameters, it is corrected by tightening the cover 6 relative to the housing 2 along section 7 (after first disconnecting the locking screws 8).

[0034] This operation does not require complete disassembly of the bearing unit or replacement of any elements of the device (bearings, seals, etc.), which increases its manufacturability without reducing the accuracy of the controlled parameters.

[0035] The design of the rotary wellhead sealer ensures the initial accuracy of the bearing position during its installation and the technological adjustment of the bearing position in the bearing assembly relative to the rotor throughout the entire period of operation.

Claims

A rotary wellhead sealer comprising a hollow housing with a vertical axial opening with a circular cross-section, in which a bearing unit is coaxially mounted, including a hollow housing of the bearing unit, a cover and bearings mounted inside the housing of the bearing unit, and a hollow rotor, characterized in that a thread is made on the inner side surface of the hollow housing of the bearing unit in the end zone on the side of the cover to a predetermined depth, and a mating thread is made on the outer side surface of the cover, which together ensure the mating of the inner side surface of the hollow housing of the bearing unit with the outer side surface of the cover when it is screwed / unscrewed.

Images