Electrically controlled variable diameter centralizer

Abstract

The present invention provides a tool for the field of oil drilling, specifically an electronically controlled variable-diameter centralizer, which includes a connection module, a control module, and a variable-diameter module. The control module includes a control unit, a solenoid valve, and an electromagnet. The control unit includes an attitude sensor. When it detects that the attitude change exceeds the threshold, the control unit changes the flow path of the drilling fluid by controlling the on / off state of the solenoid valve, providing a power source for the subsequent variable-diameter module. The variable-diameter module includes turbine blades, guide wheels, a water collecting ring, push blocks, and return springs. The water collecting ring makes the drilling fluid flow through the guide wheels from the fixed channel. The guide wheels change the flow path of the drilling fluid, causing the drilling fluid to impact the turbine blades and rotate. When the turbine blades rotate, the push blocks extend, and the push blocks fit against the pipe wall, keeping the tool in a centered position. When the solenoid valve is closed, the return springs reset the push blocks. The centralizing principle of the present invention is simple, which can effectively correct well deviation and thus improve the drilling efficiency.

Description

Technical Field

[0001] The present invention is applicable to the field of oil drilling, and particularly relates to an electronically controlled variable-diameter centralizer. Background Art

[0002] During the oil drilling process, due to the heterogeneity of the formation and the complexity of the wellbore trajectory, the drill string is prone to deviation and deflection. This not only causes deviation of the wellbore trajectory but may also trigger accidents such as wellbore wall collapse and pipe sticking, affecting the drilling efficiency and safety. To solve this problem, downhole centralizers came into being.

[0003] Traditional downhole centralizers mostly adopt mechanical structures. Such centralizers keep the drill string at the center of the wellbore through springs or mechanical forces, thereby reducing the friction between the drill string and the wellbore wall and increasing the drilling speed. However, with the increase of drilling depth and the complication of formation conditions, traditional centralizers gradually show deficiencies when dealing with working conditions such as high temperature and high pressure and complex wellbore curves, such as poor centralizing effect, easy damage, and complex operation.

[0004] In recent years, with the development of the oil industry, intelligent control technology can integrate sensors, actuators, and control systems to monitor downhole environmental parameters in real time, automatically adjust the centralizing force and centralizing direction according to the detected parameters, adapt to complex downhole working conditions, and further improve the drilling efficiency and safety. Summary of the Invention

[0005] The purpose of the present invention is to propose an electronically controlled variable-diameter centralizer to solve the problems in the above background, and combined with intelligent control, effectively improve the work of the centralizer, thereby improving the drilling efficiency.

[0006] To solve the above problems, the technical solution adopted by the present invention: The electronically controlled variable-diameter centralizer includes a connection module, a control module, and a variable-diameter module.

[0007] The connection module includes an upper sub, an upper mandrel, an upper sealing ring, an upper end cap, a lower end cap, a lower sealing ring, a lower mandrel, and a lower sub. The upper sub is threadedly connected to the upper end cap. The upper sealing rings are placed in the annular grooves on the inner wall of the upper end cap, with 4 evenly distributed axially. The upper mandrel is threadedly connected to the upper sub, and there is an interference fit between the upper mandrel and the upper end cap. The outer diameter of the upper mandrel and the inner diameter of the upper sealing ring are in interference fit. The lower sealing rings are placed in the annular grooves on the inner wall of the lower end cap, with 3 evenly distributed axially. The lower sub is threadedly connected to the lower end cap. The lower mandrel is threadedly connected to the lower sub. There is an interference fit between the lower mandrel and the lower end cap. The outer diameter of the lower mandrel and the inner diameter of the lower sealing ring are in interference fit. Both the upper sub and the lower sub are used to connect the drill strings above and below. Both the upper sealing ring and the lower sealing ring are used to prevent liquid from entering to ensure a dry internal environment.

[0008] The control module includes a control unit, a battery pack, a control unit base, a solenoid valve, an electromagnet, an electromagnet housing, an armature return spring, and an armature. The control unit is bolted to the control unit base. The control unit includes an attitude sensor, an MCU, a filtering circuit, an amplifying circuit, a voltage stabilizing circuit, and is integrated on a PCB. The attitude sensor converts the current angular velocity signal into a digital signal through an ADC and collects it, then transmits it to the MCU. When the deviation exceeds the set threshold, the solenoid valve is controlled to open and the on / off state of the electromagnet is controlled. The battery pack is connected to the control unit base through a bracket under the battery pack to supply power to the control unit. The control unit base is threadedly connected to the variable-diameter housing. The solenoid valve and the electromagnet are connected to the upper control unit and the battery pack through wires, and waterproof treatment is done at the connection points. The wires are laid in a wire groove provided on the inner wall of the variable-diameter housing. The solenoid valve is fixed to the outside of the upper core shaft by bolts and is concentric with the flow channel of the upper core shaft. The number of solenoid valves is 3, evenly distributed circumferentially. The electromagnet is threadedly connected to the electromagnet housing. The armature is placed inside the electromagnet housing, and there is a clearance fit between the armature and the electromagnet housing. The armature return spring is connected between the electromagnet housing and the armature, and after the electromagnet is powered off, the armature return spring returns the armature to its original position. The electromagnet housing is fixed to the inside of the variable-diameter housing by bolts. The number of the electromagnet, the electromagnet housing, the armature return spring, and the armature is 6, evenly distributed circumferentially, and is used for the self-locking of the push block in the extended and retracted states.

[0009] The variable diameter module includes a variable diameter outer shell, a water collecting ring, a guide wheel, a round head flat key, a thrust ball bearing, turbine blades, a shaft retaining ring, a push block return spring, a push block, a one-way valve, a wear-reducing ring, and a lower outer shell. The upper end of the variable diameter outer shell is connected to the upper end cover by a thread. The water collecting ring is connected to the upper core shaft by a thread. Three water collecting ring channels are designed in the water collecting ring and are evenly distributed along the circumference. The axial direction of the water collecting ring channels is in the same plane as the flow channel of the upper core shaft, so that the liquid flows more concentratedly downward to the guide wheel. The guide wheel and the upper core shaft are in transition fit and are axially fixed by a round head flat key to prevent circumferential rotation. The turbine blades and the upper core shaft are in clearance fit. The shaft retaining ring is stuck in the card slot on the outer diameter of the upper core shaft to axially fix the turbine blades. The thrust ball bearing is connected between the guide wheel and the turbine blades. The push block return spring is connected between the push block and the variable diameter outer shell. Two push block return springs are in a group and are placed on both sides of the push block, with a total of six groups evenly distributed along the circumference. After the tool works, the push block return spring resets the push block. The upper end of the push block is connected to the guide rail of the turbine blade and is circumferentially placed in the variable diameter slot provided at the lower end of the variable diameter outer shell. The variable diameter slot is used to ensure the radial movement of the push block. The liquid impacts the turbine blades through the guide wheel, causing the turbine blades to rotate and pushing the push block to extend radially. The push block gives a force to the wellbore wall, making the drill string in the central position and achieving the function of straightening. A self-locking card slot is provided on the push block to cooperate with the armature to ensure the self-locking of the push block during operation. The one-way valve is connected in the one-way slot at the lower end of the variable diameter outer shell by a thread. The number of one-way valves is six and they are evenly distributed along the circumference for liquid discharge. The wear-reducing ring is connected to the lower end of the variable diameter outer shell by bolts and contacts the lower end of the push block to reduce the friction when the push block is pushed out. The lower outer shell is connected to the wear-reducing ring by a thread, and the lower outer shell is connected to the lower end cover by a thread.

[0010] As a further technical solution of the present invention, the one-way valve and the push block are circumferentially staggered by 30°, avoiding the liquid discharged from the one-way valve impacting the push block, reducing the loss of the push block, and reducing the influence on the centering degree.

[0011] As a further technical solution of the present invention, the cavity formed by the control unit base and the upper end cover is used to place the control unit and the battery pack. Through the upper sealing ring, the upper end cover and the control unit base ensure the dryness of the cavity and prevent liquid from entering the control unit.

[0012] As a further technical solution of the present invention, the lower end of the variable diameter outer shell is provided with push block return spring outer shell spring card slots, two in a group, a total of six groups, evenly distributed circumferentially at 60°. Push block spring slots are provided on both sides of the push block, which are used together with the outer shell spring card slots for the axial fixation of the push block return spring, avoiding any swing of the push block return spring.

[0013] As a further technical solution of the present invention, the water accumulation ring, guide wheel, turbine blade, and push block are all made of Ti-6242S material, which has super high temperature and high pressure resistance, corrosion resistance, and wear resistance to adapt to the extreme downhole environment.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] 1. By adopting intelligent control technology, integrating sensors and actuators, it can react more sensitively to the inclination of the drill string, enabling precise control and real-time adjustment of the drill string. This precision allows the stabilizer to automatically adjust according to the downhole environment.

[0016] 2. The push block is pushed out by using the method of the drilling fluid impacting the rotation of the turbine blade. The push blocks are connected together through the turbine blade, which can ensure that the push block is fully pushed out, the drill string has a higher centering degree, and the variable diameter module can make the tool suitable for use with different pipe diameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of the present invention;

[0018] Figure 2 is a sectional view taken along line A-A;

[0019] Figure 3 is an axonometric view of the variable diameter housing;

[0020] Figure 4 is an axonometric view of the water accumulation ring;

[0021] Figure 5 is an axonometric view of the turbine blade;

[0022] Figure 6 is an axonometric view of the push block;

[0023] Figure 7 is a sectional view of the upper core shaft;

[0024] Figure 8 is a control flow chart;

[0025] Figure 9 is the execution process of the attitude sensor;

[0026] In the figure: 1 - upper connector, 2 - upper mandrel, 201 - upper mandrel flow channel, 3 - upper sealing ring, 4 - upper end cover, 5 - reducing-diameter housing, 501 - reducing-diameter notch, 502 - one-way groove, 503 - housing spring slot, 6 - control unit, 7 - battery pack, 8 - control unit base, 9 - solenoid valve, 10 - water-collecting ring, 1001 - water-collecting ring flow channel, 11 - guide wheel, 12 - round head flat key, 13 - thrust ball bearing, 14 - turbine blade, 1401 - turbine blade guide rail, 15 - shaft retaining ring, 16 - electromagnet, 17 - electromagnet housing, 18 - armature return spring, 19 - armature, 20 - push block return spring, 21 - push block, 2101 - self-locking slot, 2102 - push block spring slot, 22 - one-way valve, 23 - antifriction ring, 24 - lower housing, 25 - lower end cover, 26 - lower sealing ring, 27 - lower mandrel, 28 - lower connector. Detailed implementation manners

[0027] The technical solutions of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. These embodiments are only a part of the present invention, not all of it. Other embodiments obtained by those of ordinary skill in the art without creative efforts based on these embodiments are also within the protection scope of the present invention.

[0028] Refer to Figure 1 , an electronically controlled reducing-diameter centralizer, characterized in that: the electronically controlled reducing-diameter centralizer includes a connection module, a control module, and a reducing-diameter module.

[0029] The connection module includes an upper connector 1, an upper mandrel 2, an upper sealing ring 3, an upper end cover 4, a lower end cover 25, a lower sealing ring 26, a lower mandrel 27, and a lower connector 28. The upper connector 1 is threadedly connected to the upper end cover 4. The upper sealing ring 3 is placed in the annular groove on the inner wall of the upper end cover 4, and 4 are evenly distributed axially. The upper mandrel 2 is threadedly connected to the upper connector 1, and there is an interference fit between the upper mandrel 2 and the upper end cover 4. The outer diameter of the upper mandrel 2 and the inner diameter of the upper sealing ring 3 are in interference fit. The lower sealing ring 26 is placed in the annular groove on the inner wall of the lower end cover 25, and 3 are evenly distributed axially. The lower connector 28 is threadedly connected to the lower end cover 25. The lower mandrel 27 is threadedly connected to the lower connector 28. There is an interference fit between the lower mandrel 27 and the lower end cover 25. The outer diameter of the lower mandrel 27 and the inner diameter of the lower sealing ring 26 are in interference fit. Both the upper connector 1 and the lower connector 28 are used to connect the upper and lower drill strings, and both the upper sealing ring 3 and the lower sealing ring 26 are used to prevent liquid from entering to ensure a dry internal environment.

[0030] The control module includes a control unit 6, a battery pack 7, a control unit base 8, a solenoid valve 9, an electromagnet 16, an electromagnet housing 17, an armature return spring 18, and an armature 19. The control unit 6 is bolted to the control unit base 8. The control unit 6 includes an attitude sensor, an MCU, a filter circuit, an amplifier circuit, a voltage regulator circuit, and is integrated on a PCB. The attitude sensor converts the current angular velocity signal into a digital signal through an ADC and collects it, then transmits it to the MCU. When the deviation exceeds the set threshold, the solenoid valve 9 is controlled to open, as well as the on / off state of the electromagnet 16. The battery pack 7 is connected to the control unit base 8 through a bracket below the battery pack 7 to supply power to the control unit 6. The control unit base 8 is threadedly connected to the reduced-diameter housing 5. The solenoid valve 9 and the electromagnet 16 are connected to the upper control unit 6 and the battery pack 7 through wires, and waterproof treatment is performed at the connection. The wires are laid in a wire groove provided on the inner wall of the reduced-diameter housing 5. The solenoid valve 9 is fixed to the outside of the upper mandrel by bolts and is concentric with the upper mandrel flow channel 201. The number of solenoid valves 9 is 3 and they are evenly distributed circumferentially. The electromagnet 16 is threadedly connected to the electromagnet housing 17. The armature 19 is placed inside the electromagnet housing 17, and there is a clearance fit between the armature 19 and the electromagnet housing 17. The armature return spring 18 is connected between the electromagnet housing 17 and the armature 19, and after the electromagnet 16 is powered off, the armature return spring 18 returns the armature 19 to its original position. The electromagnet housing 17 is fixed to the inside of the reduced-diameter housing 5 by bolts. The numbers of the electromagnet 16, the electromagnet housing 17, the armature return spring 18, and the armature 19 are all 6 and they are evenly distributed circumferentially for the self-locking of the push block 21 in the extended and retracted states.

[0031] The variable-diameter module includes a variable-diameter outer shell 5, a water-accumulating ring 10, a guide wheel 11, a round head flat key 12, a thrust ball bearing 13, turbine blades 14, a shaft retaining ring 15, a push block return spring 20, a push block 21, a check valve 22, a wear-reducing ring 23, and a lower outer shell 24. The upper end of the variable-diameter outer shell 5 is threadedly connected to the upper end cover 4. The water-accumulating ring 10 is threadedly connected to the upper mandrel 2. Three water-accumulating flow channels 1001 are designed in the water-accumulating ring 10 and are evenly distributed circumferentially. The axial direction of the water-accumulating flow channels 1001 is in the same plane as the upper mandrel flow channel 201, so that the liquid flows more concentratedly downward to the guide wheel 11. The guide wheel 11 and the upper mandrel 2 adopt an interference fit and are axially fixed by a round head flat key 12 to prevent circumferential rotation. The turbine blades 14 and the upper mandrel 2 adopt a clearance fit. The shaft retaining ring 15 is clamped in the card slot on the outer diameter of the upper mandrel 2 for axial fixation of the turbine blades 14. The thrust ball bearing 13 is connected between the guide wheel 11 and the turbine blades 14. The push block return spring 20 is connected between the push block 21 and the variable-diameter outer shell 5. Two push block return springs 20 are in a group and are placed on both sides of the push block 21, with a total of 6 groups evenly distributed circumferentially. After the tool works, the push block return spring 20 returns the push block 21. The upper end of the push block 21 is connected to the turbine blade guide rail 1401 and is circumferentially placed in the variable-diameter notch 501 provided at the lower end of the variable-diameter outer shell 5. The variable-diameter notch 501 is used to ensure the radial movement of the push block 21. The liquid impacts the turbine blades 14 through the guide wheel 11, causing the turbine blades 14 to rotate and pushing the push block 21 to extend radially. The push block 21 gives a force to the wellbore wall, making the drill string in the central position and achieving the effect of straightening. A self-locking card slot 2101 is provided on the push block 21 for cooperation with the armature 19 to ensure the self-locking of the push block 21 during operation. The check valve 22 is threadedly connected in the check valve groove 502 at the lower end of the variable-diameter outer shell 5. The number of check valves 22 is 6 and they are evenly distributed circumferentially for liquid discharge. The wear-reducing ring 23 is bolted to the lower end of the variable-diameter outer shell 5 and contacts the lower end of the push block 21 to reduce the friction when the push block 21 is pushed out. The lower outer shell 24 is threadedly connected to the wear-reducing ring 23, and the lower outer shell 24 is threadedly connected to the lower end cover 25.

[0032] In this example, the control module and the variable-diameter module are the core modules of the electronically controlled variable-diameter centralizer. The control module real-time detects the attitude of the drill string through the internal attitude sensor. When the attitude of the drill string exceeds the set threshold, the control solenoid valve 9 is opened and the electromagnet 16 is energized. The drilling fluid flows into the variable-diameter module through the solenoid valve 9. After the electromagnet 16 is energized, it adsorbs the armature 19 to move upward. The drilling fluid impacts the turbine blades 14 through it, causing them to rotate and pushing out the push block 21, making the push block 21 fit the wellbore wall to achieve the straightening effect. After the straightening is completed, the push block 21 returns to its original position under the action of the push block return spring 20. The electromagnet 16 is powered off, and the armature return spring 18 returns the armature to its original position, making it in the card slot on the surface of the push block to prevent the push block 21 from moving arbitrarily.

[0033] In a specific embodiment, during the operation of the electronically controlled variable-diameter centralizer, the upper sub 1 and the lower sub 28 are respectively connected to the drill strings above and below. After the electronically controlled variable-diameter centralizer enters the wellbore, the control unit 6 detects that the current attitude exceeds the set threshold, and controls the solenoid valve 9 and the electromagnet 16 to open. After the electromagnet 16 is energized, the armature 19 is lifted upward, and the armature return spring 18 is compressed, unlocking the push block 21. The drilling fluid in the upper mandrel 2 enters the variable-diameter module through the upper mandrel flow channel 201. After the drilling fluid enters, the water-collecting ring 10 concentrates the drilling fluid and flows it to the guide wheel 11 through the water-collecting ring flow channel 1001. The drilling fluid changes its flow direction through the guide wheel 11 and impacts the lower turbine blade 14, causing the turbine blade 14 to rotate. The drilling fluid flows into the peripheral space through the check valve 22, and provides a fixed trajectory through the combination of the lower turbine blade guide rail 1401 and the variable-diameter notch 501. The rotation of the turbine blade 14 pushes out the push block 21, and the push block 21 presses against the pipe wall to exert a force on the pipe wall, keeping the drill string in the middle position. During the process of the push block 21 being pushed out, the push block return spring 20 is compressed. The control unit 6 detects the angle values in the current X and Y directions. If it is within the range of 5°, the control unit 6 closes the solenoid valve 9, and the push block 21 returns to its original position under the action of the push block return spring 20. The electromagnet 16 is de-energized, and the armature return spring 18 releases pressure to reset the armature 19 to cooperate with the self-locking card slot 2101 to restrict the movement of the push block 21. If it exceeds 5°, the solenoid valve 9 and the electromagnet 16 continue to be opened until the angle value is within the range of 5°.

Claims

1. Electrically controlled variable diameter centralizer, characterized in that: The electronically controlled variable-diameter centralizer includes a connection module, a control module, and a variable-diameter module; The connection module includes an upper sub (1), an upper mandrel (2), an upper sealing ring (3), an upper end cap (4), a lower end cap (25), a lower sealing ring (26), a lower mandrel (27), and a lower sub (28). The upper sub (1) is threadedly connected to the upper end cap (4). The upper sealing ring (3) is placed in the annular groove on the inner wall of the upper end cap (4), with 4 evenly distributed axially. The upper mandrel (2) is threadedly connected to the upper sub (1). There is an interference fit between the upper mandrel (2) and the upper end cap (4). The outer diameter of the upper mandrel (2) and the inner diameter of the upper sealing ring (3) are in interference fit. The lower sealing ring (26) is placed in the annular groove on the inner wall of the lower end cap (25), with 3 evenly distributed axially. The lower sub (28) is threadedly connected to the lower end cap (25). The lower mandrel (27) is threadedly connected to the lower sub (28). There is an interference fit between the lower mandrel (27) and the lower end cap (25). The outer diameter of the lower mandrel (27) and the inner diameter of the lower sealing ring (26) are in interference fit. Both the upper sub (1) and the lower sub (28) are used to connect the upper and lower drill strings. Both the upper sealing ring (3) and the lower sealing ring (26) are used to prevent liquid from entering to ensure a dry internal environment; The control module comprises a control unit (6), a battery pack (7), a control unit base (8), a solenoid valve (9), an electromagnet (16), an electromagnet housing (17), an armature return spring (18), and an armature (19). The control unit (6) is connected to the control unit base (8) by bolts. The control unit (6) comprises a posture sensor, an MCU, a filtering circuit, an amplifying circuit, and a voltage stabilizing circuit, and is integrated on a PCB. The posture sensor converts a current angular velocity signal into a digital signal through an ADC, collects the signal, and transmits the signal to the MCU. When the deviation angle exceeds a set threshold, the solenoid valve (9) is controlled to open, and the on / off state of the electromagnet (16) is controlled. The battery pack (7) is connected to the control unit base (8) by a bracket below the battery pack (7) to supply power to the control unit (6). The control unit base (8) is connected to the variable diameter housing (5) by threads. The solenoid valve (9) and the electromagnet (16) are connected to the upper control unit (6) and the battery pack by wires. The electromagnetic valve (9) is fixed to the outer side of the upper core shaft by bolts and is concentric with the flow channel (201) of the upper core shaft. The number of the electromagnetic valves (9) is 3 and they are evenly distributed along the circumference. The electromagnet (16) is connected to the electromagnet housing (17) by threads. The armature (19) is placed inside the electromagnet housing (17). There is a clearance fit between the armature (19) and the electromagnet housing (17). The armature return spring (18) is connected between the electromagnet housing (17) and the armature (19). After the electromagnet (16) is powered off, the armature return spring (18) returns the armature (19). The electromagnet housing (17) is fixed in the reducer housing (5) by bolts. The electromagnet (16), the electromagnet housing (17), the armature return spring (18) and the armature (19) are all 6 in number and are evenly distributed along the circumferential direction, and are used for self-locking the push block (21) in the extended and retracted states. The variable-diameter module includes a variable-diameter outer shell (5), a water-accumulating ring (10), a guide wheel (11), a round head flat key (12), a thrust ball bearing (13), turbine blades (14), a shaft retaining ring (15), a push block return spring (20), a push block (21), a check valve (22), a friction-reducing ring (23), and a lower outer shell (24). The upper end of the variable-diameter outer shell (5) is threadedly connected to the upper end cover (4). The water-accumulating ring (10) is threadedly connected to the upper mandrel (2). Three water-accumulating flow channels (1001) are designed inside the water-accumulating ring (10), evenly distributed circumferentially. The axial direction of the water-accumulating flow channels (1001) is in the same plane as the upper mandrel flow channel (201), so that the liquid flows more concentratedly downward to the guide wheel (11). The guide wheel (11) and the upper mandrel (2) are in transition fit and axially fixed by a round head flat key (12) to prevent circumferential rotation. The turbine blades (14) and the upper mandrel (2) are in clearance fit. The shaft retaining ring (15) is stuck in the card slot on the outer diameter of the upper mandrel (2) for axial fixation of the turbine blades (14). The thrust ball bearing (13) is connected between the guide wheel (11) and the turbine blades (14). The push block return spring (20) is connected between the push block (21) and the variable-diameter outer shell (5). Two push block return springs (20) are in a group, placed on both sides of the push block (21), with a total of 6 groups, evenly distributed circumferentially. After the tool works, the push block return spring (20) resets the push block (21). The upper end of the push block (21) is connected to the turbine blade guide rail (1401) and circumferentially placed in the variable-diameter notch (501) provided at the lower end of the variable-diameter outer shell (5). The variable-diameter notch (501) is used to ensure the radial movement of the push block (21). The liquid impacts the turbine blades (14) through the guide wheel (11), causing the turbine blades (14) to rotate, pushing the push block (21) to extend radially. The push block (21) gives a force to the wellbore wall, making the drill string in the central position to achieve the straightening effect. A self-locking card slot (2101) is provided on the push block (21) to cooperate with the armature (19) to ensure the self-locking of the push block (21) during work. The check valve (22) is threadedly connected in the one-way groove (502) at the lower end of the variable-diameter outer shell (5). The number of check valves (22) is 6, evenly distributed circumferentially, for liquid discharge. The friction-reducing ring (23) is bolted to the lower end of the variable-diameter outer shell (5) and contacts the lower end of the push block (21) to reduce the friction when the push block (21) is pushed out. The lower outer shell (24) is threadedly connected to the friction-reducing ring (23), and the lower outer shell (24) is threadedly connected to the lower end cover (25).

2. The electric variable-diameter centralizer according to claim 1, wherein: The check valve (22) and the push block (21) are circumferentially staggered by 30° to avoid the liquid discharged by the check valve (22) impacting the push block (21), reducing the loss of the push block (21) and the influence on the centralization degree.

3. The electric variable diameter centralizer according to claim 1, characterized in that: The cavity formed by the control unit base (8) and the upper end cover (4) is used to place the control unit (6) and the battery pack (7). Through the upper sealing ring (3), the upper end cover (4) and the control unit base (8) ensure the dryness inside the cavity and prevent liquid from entering the control unit (6).

4. The electric control variable diameter centralizer according to claim 1, characterized in that: At the lower end of the variable-diameter housing (5), there are push block return springs (20) and housing spring slots (503). Two of them form a group, and there are a total of 6 groups, evenly distributed along the circumference. On both sides of the push block (21), there are push block spring slots (2102), which are jointly used with the housing spring slots (503) for the axial fixation of the push block return spring (20) to prevent the push block return spring (20) from swinging arbitrarily.

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