Double-rubber-core rotary sealing device

Abstract

The invention belongs to the field of unbalanced drilling, and particularly relates to a double-rubber-core rotary sealing device. According to the technical scheme, the double-rubber-core rotary sealing device comprises an upper rotary module, a hoop, a bearing assembly, a lower rotary module and a shell assembly. The upper rotating module comprises an upper shell, an upper rubber core, an oil duct, an upper bearing, a rotating sealing ring and an upper rubber core pressing plate; the bearing assembly comprises a tapered roller bearing, an inner cylinder, a cylindrical roller bearing, a sleeve and a bearing gland; the lower rotating module comprises a lower bearing, a connecting piece and a lower rubber core; the shell assembly comprises an adaptive ring, an upper O-shaped sealing ring, an outer cylinder, a lower O-shaped sealing ring, a shell and a lower cover plate; according to the double-rubber-core rotary sealing device, the upper rubber core and the lower rubber core can be intelligently controlled to alternately work, the service life of the rubber cores is prolonged, the wellhead pressure is controlled for a longer time, and therefore unbalanced drilling is completed, and the drilling speed is increased.

Description

Technical Field

[0001] The invention belongs to the field of underbalanced drilling, geothermal drilling and coal gas layer drilling, and in particular relates to a double-rubber core rotary sealing device. Background Art

[0002] The double-rubber core rotary seal device is a key equipment in the field of oil drilling technology, especially in the implementation of gas drilling, underbalanced drilling and controlled pressure drilling and other wellbore pressure control operations. It acts as a seal between the wellbore annulus and the pipe string, provides safe and effective pressure control, and guides the fluid returned from the wellbore away from the wellhead. However, there are some limitations in the double-rubber core rotary seal device in the prior art. Most of the double-rubber core rotary seal devices used in underbalanced drilling in my country rely on imports, some key technologies are kept secret in my country, and wearing parts such as sealing rubber rings are completely imported. This not only has a relatively high economic cost, but also is technically controlled by others, hindering the development of underbalanced technology in China. Therefore, it is currently most needed to design a rotary seal device that is suitable for high-pressure underbalanced drilling, has good sealing effect, and has a long service life of the rubber core. Summary of the invention

[0003] The purpose of the present invention is to provide a double-rubber core rotary sealing device, which intelligently controls two rubber cores to alternately hold the drill pipe, thereby reducing the wear of the sealing rubber core and extending the service life, thereby improving the efficiency of underbalanced drilling.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a double-rubber core rotary sealing device, characterized in that: it includes an upper rotary module, a clamp, a bearing assembly, a lower rotary module, and a shell assembly; the upper rotary module includes an upper outer shell, an upper rubber core, an oil channel, an upper bearing, a rotary sealing ring, and an upper rubber core pressure plate; the bearing assembly includes a tapered roller bearing, an inner cylinder, a cylindrical roller bearing, a sleeve, and a bearing pressure cover; the lower rotary module includes a lower bearing, a connecting piece, and a lower rubber core; the shell assembly includes an adapter ring, an upper O-ring, an outer cylinder, a lower O-ring, a shell, and a lower cover plate.

[0005] The upper rubber core is installed in the upper shell in an interference fit manner. Oil passages are opened on one side of the upper shell and the upper rubber core for conveying hydraulic oil to the upper rubber core to seal the drill pipe. The rotary seal ring adopts a Kalsi dynamic seal, which is installed between the upper shell and the clamp to isolate external impurities and the liquid inside the device. The upper rubber core pressure plate is connected to the upper shell by 8 bolts. There is a pair of tapered roller bearings in the bearing assembly, which are mainly used to withstand the vertical upward liquid pressure from the mud. One is installed on the uppermost stepped shaft of the inner tube, and the other is installed on the lowermost stepped shaft of the inner tube. There is a pair of cylindrical roller bearings in the bearing assembly, which play a straightening role and are installed separately. Installed on the two stepped shafts in the middle of the inner cylinder; the sleeve is installed between the two cylindrical roller bearings in an interference fit manner, and plays a positioning role for the two cylindrical roller bearings; the adapter ring is connected to the outer cylinder by threads, and the lower end of the outer cylinder is connected to the shell by threads, and an O-ring is installed at the connection to prevent external impurities from entering the interior of the double-rubber core rotary sealing device; the sleeve and the outer cylinder are fitted in an interference fit manner; the bearing gland is installed in the shell in an interference fit manner, and the lower bearing is installed between the bearing gland, the connecting piece and the shell, the outer end shoulder of the connecting piece is clamped on the inner ring of the lower bearing, the lower rubber core and the connecting piece are fixed by 8 bolts, and the shell and the lower cover plate are fixed by 8 bolts.

[0006] The clamp is of two-petal type and is installed between the upper bearing and the adapter ring in an interference fit manner, and is used to connect the upper rotating module and the shell assembly; an O-ring is provided between the inner cylinder and the upper rubber core pressure plate and the connecting piece to prevent mud from flowing into the bearing assembly; wireless displacement sensors are embedded in the main sealing surfaces of the upper rubber core and the lower rubber core to measure the radial movement distance between the upper rubber core and the upper shell, and between the lower rubber core and the shell.

[0007] A bypass channel is provided on one side of the shell body for draining mud liquid.

[0008] Compared with the prior art, the present invention has the following beneficial effects: (1) The modular design of each part of the device is convenient for maintenance and replacement; (2) The device adopts two rotating rubber cores, and detects the radial movement distance of the rubber core through a displacement sensor, and indirectly detects the position of the drill pipe joint, so that the upper rubber core and the lower rubber core work alternately to achieve intermittent sealing, prevent the drill pipe joint from tearing and impacting the sealing rubber core, thereby reducing damage to the sealing rubber core and improving the use efficiency of the rubber core. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative labor.

[0010] Figure 1 It is a full cross-sectional view of a double-core rotary seal device.

[0011] The accompanying drawings are only used to illustrate the principles of the present invention and are not drawn according to the actual scale.

[0012] Among them: 1-upper shell, 2-upper rubber core, 3-oil channel, 4-clamp, 5-upper bearing, 6-rotating sealing ring, 7-upper rubber core pressure plate, 8-adapter ring, 9-tapered roller bearing, 10-upper O-ring, 11-inner cylinder, 12-cylindrical roller bearing, 13-sleeve, 14-outer cylinder, 15-lower O-ring, 16-bearing pressure cover, 17-lower bearing, 18-connecting piece, 19-lower rubber core, 20-shell, 21-lower cover. DETAILED DESCRIPTION

[0013] See attached Figure 1 The double-rubber core rotary sealing device mainly includes: an upper rotary module, a clamp 4, a bearing assembly, a lower rotary module, and a shell assembly; the upper rotary module includes an upper shell 2, an upper rubber core 2, an oil channel 3, an upper bearing 5, a rotary sealing ring 6, and an upper rubber core pressure plate 7; the bearing assembly includes a tapered roller bearing 9, an inner cylinder 11, a cylindrical roller bearing 12, a sleeve 13, and a bearing pressure cover 16; the lower rotary module includes a lower bearing 17, a connecting piece 18, and a lower rubber core 19; the shell assembly includes an adapter ring 8, an upper O-ring 10, an outer cylinder 14, a lower O-ring 15, a shell 20, and a lower cover plate 21.

[0014] The upper rubber core 2 is installed in the upper shell 1 in an interference fit manner. An oil channel 3 is opened on one side of the upper shell 1 and the upper rubber core 2, which is used to transport hydraulic oil to the upper rubber core 2 to seal the drill pipe; the rotary seal ring 6 adopts a Kalsi dynamic seal, which is installed between the upper shell 1 and the clamp 4 to isolate external impurities and the liquid inside the device; the upper rubber core pressure plate 7 is connected to the upper shell 1 by 8 bolts; there is a pair of tapered roller bearings 9 in the bearing assembly, which are mainly used to withstand the vertical upward liquid pressure from the mud, one is installed on the uppermost stepped shaft of the inner cylinder 11, and the other is installed on the lowermost stepped shaft of the inner cylinder 11; there is a pair of cylindrical roller bearings 12 in the bearing assembly, which play a straightening role and are respectively installed on the two steps in the middle of the inner cylinder 11 The sleeve 13 is installed between the two cylindrical roller bearings 12 in an interference fit manner, and plays a positioning role for the two cylindrical roller bearings 12; the adapter ring 8 is connected to the outer cylinder 14 by threads, and the lower end of the outer cylinder 14 is connected to the housing 20 by threads, and an O-ring 15 is installed at the connection to prevent external impurities from entering the interior of the double rubber core rotary sealing device; the sleeve 13 and the outer cylinder 14 are fitted in an interference fit manner; the bearing gland 16 is installed in the housing 20 in an interference fit manner, and the lower bearing 17 is installed between the bearing gland 16, the connecting piece 18 and the housing 20, and the outer end shoulder of the connecting piece 18 is clamped on the inner ring of the lower bearing 17, the lower rubber core 19 and the connecting piece 18 are fixed by 8 bolts, and the housing 20 and the lower cover plate 21 are fixed by 8 bolts. When the double-rubber core rotary sealing device is working, the housing assembly, the clamp 4, the sleeve 13, the outer ring of the tapered roller bearing 9, and the outer ring of the cylindrical roller bearing 12 remain stationary, and the upper rotary module, the inner cylinder 11, the inner ring of the tapered roller bearing 9, the inner ring of the cylindrical roller bearing 12, and the lower rotary module rotate.

[0015] The clamp 4 is of two-petal type and is installed between the upper bearing 5 and the adapter ring 8 in an interference fit manner, and is used to connect the upper rotating module and the shell assembly; an O-ring is provided between the inner cylinder 11 and the upper rubber core pressure plate 7 and the connecting piece 18 to prevent mud from flowing into the bearing assembly; wireless displacement sensors are embedded in the main sealing surfaces of the upper rubber core 2 and the lower rubber core 19 to measure the radial movement distance between the upper rubber core 7 and the upper shell 1, and the lower rubber core 19 and the shell 20.

[0016] A bypass channel is opened on one side of the shell for high-pressure hydraulic oil to enter the lower rubber core to seal the drill rod.

[0017] The working process of the double rubber core rotary sealing device of the present invention is as follows: in the underbalanced drilling process, the upper rubber core is in an open state in the initial state, sealing the drill pipe, and the lower rubber core is in a naturally relaxed state. When the drill pipe joint approaches the upper rubber core during the drilling process, the wireless displacement sensor in the upper rubber core detects that the distance between the rubber core and the upper shell is reduced to the set distance and then sends a signal to the electronic control system to control the lower hydraulic system to start oil injection to the lower rubber core to hold the drill pipe tightly. When the lower rubber core is fully opened, the upper rubber core is controlled to return oil. At this time, the lower rubber core works and the upper rubber core is in a relaxed state, so that the drill pipe joint passes smoothly through the upper rubber core. When the drill pipe joint approaches the lower rubber core, the wireless displacement sensor in the lower rubber core detects that the distance between the rubber core and the shell begins to decrease to the set distance and then sends a signal to the electronic control system to control the upper hydraulic system to start oil injection to the upper rubber core to hold the drill pipe tightly. When the upper rubber core is fully opened, the lower rubber core is controlled to return oil, so that the drill pipe joint passes smoothly through the lower rubber core. The upper and lower rubber cores are opened and closed in turn, and work alternately to ensure that at least one rubber core is in a sealed state. While ensuring reliable sealing, it increases the service life of the rubber core and reduces the replacement frequency of the rubber core.

[0018] The double-rubber core rotary sealing device provided by the present invention realizes the drill pipe sealing in the underbalanced drilling process by using two rubber cores to work alternately, thereby improving the service life of the rubber core. It has the characteristics of simplicity, high efficiency, wide applicability, etc., and is original and practical, and is of great significance for ensuring the safety of my country's energy production.

[0019] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. Double rubber core rotary sealing device, characterized by: The invention comprises an upper rotating module, a clamp (4), a bearing assembly, a lower rotating module and a housing assembly; the upper rotating module comprises an upper housing (1), an upper rubber core (2), an oil passage (3), an upper bearing (5), a rotating sealing ring (6) and an upper rubber core pressure plate (7); the bearing assembly comprises a tapered roller bearing (9), an inner cylinder (11), a cylindrical roller bearing (12), a sleeve (13) and a bearing pressure cover (16); the lower rotating module comprises a lower bearing (17), a connecting piece (18) and a lower rubber core (19); the housing assembly comprises an adapter ring (8), an upper O-ring (10), an outer cylinder (14), a lower O-ring (15), a housing (20) and a lower cover plate (21); The upper rubber core (2) is installed in the upper shell (1) in an interference fit manner, and an oil passage (3) is opened on one side of the upper shell (1) and the upper rubber core (2); the rotary seal ring (6) is installed between the upper shell (1) and the clamp (4); the upper rubber core pressure plate (7) is connected to the upper shell (1) by bolts; the bearing assembly includes a pair of tapered roller bearings (9), one of which is installed on the uppermost stepped shaft of the inner cylinder (11) and the other is installed on the lowermost stepped shaft of the inner cylinder (11); the bearing assembly includes a pair of cylindrical roller bearings (12), which are respectively installed on the two stepped shafts in the middle of the inner cylinder (11). The sleeve (13) is installed between the two cylindrical roller bearings (12) in an interference fit manner; the adapter ring (8) is connected to the outer cylinder (14) by threads, and the outer cylinder (14) is connected to the housing (20) by threads; the sleeve (13) and the outer cylinder (14) are fitted in an interference fit manner; the bearing cover (16) is installed in the housing (20) in an interference fit manner, and the lower bearing (17) is installed between the bearing cover (16) and the housing (20); the outer end shoulder of the connecting piece (18) is clamped on the inner ring of the lower bearing (17), and the lower rubber core (19) and the connecting piece (18) are fixed by bolts.

2. The clamp (4) is of a two-petal type and is installed between the upper bearing (5) and the adapter ring (8) in an interference fit manner; a sealing ring is provided between the inner cylinder (11) and the upper rubber core pressure plate (7) and the connecting piece (18); the lower O-ring (15) is installed between the outer cylinder (14) and the shell (20) to prevent external impurities from entering the interior of the double rubber core rotary sealing device; the shell (20) and the lower cover plate (21) are connected by bolts.

3. Wireless displacement sensors are embedded in the main sealing surfaces of the upper rubber core (7) and the lower rubber core (19) for measuring the radial movement distance between the upper rubber core (7) and the upper shell (1), and between the lower rubber core (19) and the shell (20).

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