Sealing transmission device for improving pressure bearing capacity of underground water nozzle

Abstract

The invention relates to the technical field of separate injection and separate production water nozzle sealing adjustment, and particularly discloses a sealing transmission device for improving the pressure bearing capacity of an underground water nozzle. The sealing transmission device comprises a transmission shaft, the upper end and the lower end of the transmission shaft are used for being connected with a driving mechanism and the water nozzle correspondingly, and the water nozzle is arranged in a water nozzle seat; a mounting cavity is formed in the upper portion of the water nozzle seat, the lower portion of the transmission shaft is rotationally connected with the inner wall of the water nozzle seat through a second bearing, the lower surface of the second bearing presses the upper surface of the water nozzle, the upper surface of the second bearing tightly presses the lower surface of the rigid sealing piece, and the upper surface of the rigid sealing piece tightly presses the lower surface of the pressure-bearing cover. And the rigid sealing piece is used for sealing a cavity between the transmission shaft and the water nozzle seat. Under the condition that the rotation torque is not increased, the pressure resistance of a shut-in well can be improved, the water nozzle can be normally opened and closed under the conditions of well shut-in and high pressure difference and is easy to open, and the service life of the water nozzle is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of sealing and adjusting water nozzles for injection and production, and in particular to a sealing transmission device for improving the pressure bearing capacity of underground water nozzles. Background Art

[0002] In separate injection and production, the stepless water nozzle is the key mechanism for achieving precise control of the injection and production flow rate. It must be sealed when closed and open when needed, and the flow rate can be continuously adjusted. In the existing technology, it is difficult to ensure leakage-free sealing of downhole actuators. Minor leakage of water and gas will form a low-resistance discharge channel in the downhole battery compartment, shortening the downhole working cycle of the actuator; downhole rotating seals all use friction-resistant slip ring structures, and minor leakage is difficult to avoid; increasing the pre-pressure of the friction-resistant slip ring seal will improve the sealing effect, but will also increase the rotational torque between the drive shaft and the friction-resistant slip ring seal structure, resulting in increased energy consumption of the water nozzle, or even abnormal operation, inconvenience in opening, and shortened seal life.

[0003] Downhole water nozzles need to ensure high-pressure sealing while performing high-pressure differential switching, and the differential pressure of such sealing is often as high as 35MPa or even higher. However, due to the limitation of the radial size of the wellbore, the high-pressure dynamic sealing capacity (sealing and pressure bearing) of downhole tools and instruments cannot be met by simply increasing the size or number of seals or pressure-bearing parts. In addition, when the water nozzle is closed, the existing bearing cannot meet the pressure requirements and becomes the weakest link, which is easily failed due to high pressure. Summary of the invention

[0004] The purpose of the present invention is to provide a sealing transmission device for improving the pressure bearing capacity of a downhole water nozzle, thereby improving the pressure bearing capacity of the downhole water nozzle without increasing the rotational torque, solving the problem of normal switching of the water nozzle under well sealing and high pressure difference conditions, making it easy to open and prolonging the service life of the water nozzle.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] The cam is an axially ...

[0007] In a further solution, the rigid seal comprises a sealing seat, an outer wall surface of the sealing seat and the faucet seat are sealed by a static sealing structure, and an inner wall surface of the sealing seat and the transmission shaft are sealed by a dynamic sealing structure.

[0008] In a further solution, the static sealing structure includes a sealing ring, and a sealing ring installation groove is provided on the faucet seat and the sealing seat, and the sealing ring is sealingly connected in the installation groove.

[0009] In a further solution, the dynamic sealing structure includes a friction-resistant sliding ring, the inner wall surface of the friction-resistant sliding ring is in contact with the outer wall surface of the transmission shaft, and the friction-resistant sliding ring is pressed onto the transmission shaft through an elastic sealing ring, and the elastic sealing ring is sealingly connected between the inner wall surface of the sealing seat and the outer wall surface of the friction-resistant sliding ring.

[0010] In a further solution, the longitudinal section of the friction-resistant sliding ring is "T"-shaped, the upper part of the "T" is pressed on the inner wall surface of the sealing seat, and the lower part of the "T" is pressed on the transmission shaft through the elastic sealing ring.

[0011] In a further solution, the dynamic sealing structure also includes an air sealing member arranged between the transmission shaft and the sealing seat.

[0012] In a further embodiment, the first bearing comprises a thrust bearing.

[0013] In a further embodiment, the second bearing comprises a needle roller bearing.

[0014] In a further solution, the faucet includes a fixed faucet and a movable faucet, the fixed faucet is used to be fixedly connected to the faucet seat, the movable faucet is connected between the fixed faucet and the transmission shaft, and the movable faucet is used to close or open the liquid flow channel between the fixed faucet and the faucet seat.

[0015] In a further embodiment, the driving mechanism includes a motor.

[0016] Beneficial effects of the present invention:

[0017] 1. The dual-load channel sealing device of the present invention increases the ability of the water nozzle to withstand the well sealing pressure by more than double by adding a second bearing and its load channel without increasing the rotation torque of the transmission shaft, thus solving the problem of opening the water nozzle when sealing the well and under high pressure difference conditions.

[0018] 2. The present invention distributes the load according to the working conditions, which simplifies the installation structure of the upper ball bearing on the one hand; on the other hand, it reduces the difficulty of selecting a miniature ball bearing (requiring high strength in a miniature size and withstanding a thrust of 3t-5t), thereby providing a more economical design idea for the rotation of the faucet under low pressure difference conditions (the faucet is open).

[0019] 3. The present invention arranges the two bearings at a certain distance apart, which can straighten the transmission shaft on the one hand and transfer the high pressure through the load channel on the other hand to avoid bending of the transmission shaft due to excessive end load, resulting in increased torque and affecting motor drive.

[0020] 4. The present invention increases the sealing of the airtight parts, strengthens the airtightness of the system, and further increases the service life of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 Schematic diagram of a sealing transmission device installed inside a downhole tool in an embodiment of the present invention;

[0023] Figure 2 is an external schematic diagram of a downhole tool where a sealing transmission device is installed in an embodiment of the present invention;

[0024] Figure 3 is a schematic diagram of a sealed transmission device in an embodiment of the present invention;

[0025] Figure 4 It is a schematic diagram of pressure transmission when the sealing transmission device in the embodiment of the present invention is under the positive pressure state of the liquid flow;

[0026] Figure 5 Schematic diagram of pressure transmission when the sealing transmission device in the embodiment of the present invention is subjected to reverse pressure of liquid flow;

[0027] In the figure: 1. transmission shaft; 2. driving mechanism; 3. faucet; 31. fixed faucet; 32. movable faucet; 4. faucet seat; 41. mounting cavity; 5. first bearing; 6. pressure cover; 7. rigid seal; 71. seal seat; 72. static seal structure; 73. dynamic seal structure; 731. friction-resistant sliding ring; 732. elastic sealing ring; 733. gas seal; 8. second bearing. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] like Figure 1 As shown, a sealing transmission device for improving the pressure-bearing capacity of a downhole water nozzle comprises a transmission shaft 1, wherein the upper and lower ends of the transmission shaft 1 are respectively used to connect a driving mechanism 2 and a water nozzle 3, the water nozzle 3 is arranged in a water nozzle seat 4, and is used to adjust the amount of water inlet and outlet of the water nozzle seat 4, the upper part of the transmission shaft 1 is connected with a pressure cover 6 through a first bearing 5, the upper part of the water nozzle seat 4 is provided with a mounting cavity 41, the mounting cavity 41 is used to fix the pressure cover 6, the pressure cover 6 is used to transmit the axial force of the transmission shaft 1 to the water nozzle seat 4, the lower part of the transmission shaft 1 is rotatably connected to the inner wall of the water nozzle seat 4 through a second bearing 8, the lower surface of the second bearing 8 presses the upper surface of the water nozzle 3, the upper surface of the second bearing 8 is pressed against the lower surface of the rigid seal 7, the second bearing 8 is used to transmit the axial pressure between the rigid seal 7 and the water nozzle seat 4, the upper surface of the rigid seal 7 is pressed against the lower surface of the pressure cover 6, the rigid seal 7 is used to transmit the axial pressure between the second bearing 8 and the pressure cover 6, and the rigid seal 7 is used to seal the cavity between the transmission shaft 1 and the water nozzle seat 4.

[0030] Its working principle or implementation method is to drive the transmission shaft 1 to rotate through the driving mechanism 2, thereby driving the water spout 3 to move, so as to adjust the water inlet and outlet of the water spout seat 4, and realize stepless regulation. During the adjustment process, when the water spout 3 needs to be in the water outlet state, that is, when the water spout 3 is under positive pressure and the water spout 3 is in the open state, refer to Figure 4 As shown, the second bearing 8 on the faucet 3 is not sealed, is connected to the water outlet cavity, and is in a floating state in the liquid to maintain high pressure balance. The high-pressure fluid will generate pressure on the end of the transmission shaft 1 and the rigid seal along the matching gap, and the pressure will be transmitted to the faucet seat 4 through the pressure cover 6. Figure 2As shown, at this time, because the liquid can flow out from the faucet seat 4, the upward pressure is greatly relieved, the pressure on the end of the transmission shaft 1 will be relatively small, and the influence on the rotation torque of the transmission shaft 1 will be small. The transmission shaft 1 itself will also be easy to rotate under the action of the first bearing 5, so it will not affect the stepless adjustment of the transmission shaft 1 by the driving mechanism 2 under high pressure. Figure 5 As shown, when the faucet seat 4 is not in the water outlet state, that is, the faucet 3 is in the closed state, the faucet 3 will be subjected to the reverse pressure from the downstream channel, such as the pressure of the bottom hole fluid, and generally the bottom hole fluid pressure is greater than the inlet pressure at this time, thereby pushing the faucet 3, and the pressure on the faucet 3 is transmitted to the faucet seat 4 by the second bearing 8, the rigid seal 7, and the pressure cover in sequence. At this time, the first bearing 5 at the upper end is in a floating state, and the maximum impact pressure at the bottom is basically transmitted directly to the faucet seat 4 through the rigid seal 7, which will reduce the pressure on the transmission shaft 1 and prevent the torque on the transmission shaft 1 from increasing, thereby solving the problem of opening the faucet 3 when sealing the well and under high pressure difference conditions, and can play a role in timely opening, and the ability of the faucet 3 to withstand the sealing pressure is improved.

[0031] According to the above working principle, some preferred implementation structures or methods are provided, such as Figure 3 As shown, the rigid seal 7 includes a sealing seat 71, the outer wall of the sealing seat 71 is sealed with the faucet seat 4 shown in the figure by a static sealing structure 72, and the inner wall of the sealing seat 71 is sealed with the transmission shaft 1 by a dynamic sealing structure 73. The static sealing structure 72 can prevent the fluid from passing through the gap between the sealing seat 71 and the faucet seat 4, and the dynamic sealing structure 73 can also seal the gap between the transmission shaft 1 and the sealing seat 71 when the transmission shaft 1 rotates, so that the faucet seat 4 and the driving mechanism 2, i.e., the actuator, can be completely sealed to prevent safety problems or insufficient pressure problems caused by leakage.

[0032] The static sealing structure 72 includes a sealing ring, and a sealing ring installation groove is provided on the faucet seat 4 and the sealing seat 71, and the sealing ring is sealed and connected in the installation groove. There can be multiple sealing rings.

[0033] The dynamic sealing structure 73 includes a friction-resistant sliding ring 731, the inner wall surface of the friction-resistant sliding ring 731 contacts the outer wall surface of the transmission shaft 1, and the friction-resistant sliding ring 731 is pressed on the transmission shaft 1 through an elastic sealing ring 732, and the elastic sealing ring 732 is sealed between the inner wall surface of the sealing seat 71 and the outer wall surface of the friction-resistant sliding ring 731. In this way, when the transmission shaft 1 drives the faucet 3 to be steplessly adjusted, the friction at the sealing part can be reduced, and the service life of the sealing structure can be increased.

[0034] The longitudinal section of the friction-resistant sliding ring 731 is in a "T" shape, and the upper part of the "T" is pressed on the inner wall surface of the sealing seat 71, and the lower part of the "T" is pressed on the transmission shaft 1 through the elastic sealing ring 732. This facilitates the arrangement of the elastic sealing ring 732, which can of course also be an I-shaped or other shape.

[0035] The dynamic sealing structure 73 also includes an air seal 733 disposed between the transmission shaft 1 and the sealing seat 71. Adding an air seal 733 structure can improve the wear resistance between the transmission shaft 1 and the sealing seat 71 and improve the sealing performance.

[0036] The dynamic sealing structure 73 can be a simple combined seal consisting of an O-ring and a friction-resistant sliding ring 731. The O-ring ensures the seal between the transmission shaft 1 and the sealing seat 71, and the friction-resistant sliding ring 731 ensures the seal between the transmission shaft 1 and the dynamic sealing assembly.

[0037] The first bearing 5 includes a thrust bearing. The thrust bearing can reduce the friction coefficient during the rotation of the transmission shaft 1, reduce the friction force at the end of the transmission shaft 1, and thus reduce the torque. It is particularly noted that in order to improve the load-bearing capacity of the thrust ball bearing, the bearing adopts a full ball design.

[0038] The second bearing 8 includes a needle bearing. A needle bearing is arranged below the sealing seat 71. The needle bearing can greatly improve the pressure bearing capacity of the device because the needle bearing is in line contact. Therefore, the needle bearing can increase the pressure resistance compared to the ball bearing and improve the strength of the bearing.

[0039] The faucet 3 includes a fixed faucet 31 and a movable faucet 32. The fixed faucet 31 is used to be fixedly connected to the faucet seat 4. The movable faucet 32 ​​is connected between the fixed faucet 31 and the transmission shaft 1. The movable faucet 32 ​​is used to close or open the liquid flow channel between the fixed faucet 31 and the faucet seat 4.

[0040] The driving mechanism 2 includes a motor. The motor is a common actuator with mature control technology and is easy to purchase. The motor downhole is connected to the transmission shaft 1 of the sealing device, and the lower end of the transmission shaft 1 is connected to the movable water nozzle 32. The motor drives the rotation of the movable water nozzle 32 through the transmission shaft 1, thereby adjusting the opening of the water nozzle 3.

[0041] The sealing device is fixed in the downhole tool by a pressure-bearing cap arranged at the top and the faucet seat 4, which can be threadedly connected. A sealing seat 71 is arranged below the transmission shaft 1. The outside of the sealing seat 71 is provided with multiple O-rings as static sealing devices to ensure that when working underground, liquid will not enter the motor part of the downhole tool from the outside of the sealing device.

[0042] When used specifically, Figure 4As shown, when the faucet 3 is subjected to positive pressure, the faucet 3 is in the open state, and the movable faucet 32 ​​is connected with the fixed faucet 31 at this time. The high-pressure fluid enters the working chamber of the faucet 3 through the small hole water inlet evenly distributed on the faucet seat 4, and then flows through the connecting channel of the faucet 3 to enter the downstream. At this time, because the entire needle roller bearing is not sealed, it is in a balanced state under high pressure, that is, a floating state. The high-pressure fluid acts on the dynamic seal and the end of the transmission shaft 1 along the fitting clearance. The fluid pressure acting on the end of the dynamic seal squeezes and further compacts the dynamic seal, thereby generating a clamping force in the radial direction that can increase the rotational torque of the transmission shaft 1; and the fluid pressure acting on the end of the transmission shaft 1 is transmitted to the thrust bearing, and then transmitted to the pressure cover by the thrust bearing, and then transmitted to the faucet seat 4 by the connecting thread between the pressure cover and the faucet seat 4, thereby reducing the pressure and torque on the transmission shaft 1, making it easier for the motor to control its rotation to adjust the faucet 3. The direction of the arrow is the force transmission direction. As shown Figure 5 As shown. When the faucet 3 is subjected to reverse pressure, that is, the faucet 3 is closed, the movable faucet 32 ​​is not connected to the fixed faucet 31, the upstream and downstream channels are blocked, and the inlet and outlet of the faucet 3 form corresponding pressures respectively. Sometimes the pressure on both sides reaches 35MPa, or even higher. Usually the pressure from the bottom hole fluid, that is, the outlet pressure, will be higher. Thereby pushing the fixed faucet 31, the pressure is transmitted to the faucet seat 4 in turn by the needle bearing, the sealing seat 71, the pressure cover, and the connecting thread between the pressure cover and the faucet seat 4, and the direction of the arrow is the force transmission direction. At this time, the thrust ball bearing at the upper end is in a floating state. It also reduces the pressure and torque on the drive shaft 1, making it easier for the motor to control its rotation to adjust the faucet 3.

[0043] It should be noted that the terms "first", "second" etc. in the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged in appropriate circumstances, so that the embodiments of the present application described here. In the present application, the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", "middle", "vertical", "horizontal", "lateral", "longitudinal" etc. are based on the orientation or positional relationship shown in the accompanying drawings.

[0044] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0045] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A sealed transmission device for improving the pressure bearing capacity of a downhole water nozzle, comprising a transmission shaft (1), wherein the upper and lower ends of the transmission shaft (1) are respectively used to connect a driving mechanism (2) and a water nozzle (3), wherein the water nozzle (3) is arranged in a water nozzle seat (4) and is used to adjust the water inlet and outlet of the water nozzle seat (4), characterized in that: The upper part of the transmission shaft (1) is connected to a pressure cover (6) via a first bearing (5); the upper part of the faucet seat (4) is provided with a mounting cavity (41); the mounting cavity (41) is used for fixedly connecting the pressure cover (6); the pressure cover (6) is used for transmitting the axial force of the transmission shaft (1) to the faucet seat (4); the lower part of the transmission shaft (1) is rotatably connected to the inner wall of the faucet seat (4) via a second bearing (8); the lower surface of the second bearing (8) presses against the upper surface of the faucet (3) The upper surface of the second bearing (8) is pressed against the lower surface of the rigid seal (7), and the second bearing (8) is used to transmit the axial pressure between the rigid seal (7) and the faucet seat (4). The upper surface of the rigid seal (7) is pressed against the lower surface of the pressure cover (6), and the rigid seal (7) is used to transmit the axial pressure between the second bearing (8) and the pressure cover (6), and the rigid seal (7) is used to seal the cavity between the transmission shaft (1) and the faucet seat (4).

2. A sealing transmission device for improving the pressure bearing capacity of a downhole water nozzle according to claim 1, characterized in that: The rigid sealing member (7) comprises a sealing seat (71), wherein an outer wall surface of the sealing seat (71) and the faucet seat (4) are sealed via a static sealing structure (72), and an inner wall surface of the sealing seat (71) and the transmission shaft (1) are sealed via a dynamic sealing structure (73).

3. A sealing transmission device for improving the pressure bearing capacity of a downhole water nozzle according to claim 2, characterized in that: The static sealing structure (72) comprises a sealing ring, and a sealing ring installation groove is provided on the faucet seat (4) and the sealing seat (71), and the sealing ring is sealingly connected in the installation groove.

4. A sealing transmission device for improving the pressure bearing capacity of a downhole water nozzle according to claim 2, characterized in that: The dynamic sealing structure (73) comprises a friction-resistant sliding ring (731), the inner wall surface of the friction-resistant sliding ring (731) contacts the outer wall surface of the transmission shaft (1), and the friction-resistant sliding ring (731) is pressed onto the transmission shaft (1) via an elastic sealing ring (732), and the elastic sealing ring (732) is sealingly connected between the inner wall surface of the sealing seat (71) and the outer wall surface of the friction-resistant sliding ring (731).

5. A sealing transmission device for improving the pressure bearing capacity of a downhole water nozzle according to claim 4, characterized in that: The longitudinal section of the friction-resistant sliding ring (731) is in a "T" shape, the upper part of the "T" is pressed against the inner wall surface of the sealing seat (71), and the lower part of the "T" is pressed against the transmission shaft (1) through the elastic sealing ring (732).

6. A sealing transmission device for improving the pressure bearing capacity of a downhole water nozzle according to claim 2, characterized in that: The dynamic sealing structure (73) further comprises an air sealing member (733) arranged between the transmission shaft (1) and the sealing seat (71).

7. A sealing transmission device for improving the pressure bearing capacity of a downhole water nozzle according to claim 1, characterized in that: The first bearing (5) comprises a thrust bearing.

8. A sealing transmission device for improving the pressure bearing capacity of a downhole water nozzle according to claim 1, characterized in that: The second bearing (8) comprises a needle roller bearing.

9. A sealing transmission device for improving the pressure bearing capacity of a downhole water nozzle according to claim 1, characterized in that: The water nozzle (3) comprises a fixed water nozzle (31) and a movable water nozzle (32); the fixed water nozzle (31) is used for being fixedly connected to a water nozzle seat (4); the movable water nozzle (32) is connected between the fixed water nozzle (31) and a transmission shaft (1); the movable water nozzle (32) is used for closing or opening a liquid flow channel between the fixed water nozzle (31) and the water nozzle seat (4).

10. A sealing transmission device for improving the pressure bearing capacity of a downhole water nozzle according to claim 1, characterized in that: The driving mechanism (2) comprises a motor.

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