Normally open type closed spring chamber hydraulic control sliding sleeve

Abstract

The utility model relates to the technical field of hydraulic control sliding sleeves, in particular to a normally open type closed spring cavity hydraulic control sliding sleeve which comprises an upper connector, a hydraulic cylinder, an outer pipe, a pressure transmission ring, a spring protection pipe, a spring sleeve, an adjusting spring and a lower connector. The hydraulic cylinder is in threaded connection with the outer pipe, a sealing ring is arranged at the connection position, the pressure difference inside and outside a spring cavity is automatically adjusted in the opening and closing process of the sliding sleeve, the hydraulic impact or negative pressure risk caused by volume change is eliminated, and the sealing ring is prevented from being damaged or the sliding sleeve is prevented from being clamped. A standby balance channel and a multi-stage pressure relief valve are additionally arranged, when a main balance plug is blocked or the system is overpressure, the standby channel is automatically started, the pressure relief valve relieves pressure by 25 MPa and 30 MPa step by step, structure overload is effectively prevented, and the fault-tolerant capability of the system is improved.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic control sliding sleeve technology, specifically a normally open sealed spring chamber hydraulic control sliding sleeve. Background Technology

[0002] As is well known, normally open hydraulic control sleeves are a key downhole tool in oil and gas field completion operations, used to open and close production channels in specific oil and gas reservoirs via hydraulic control. In existing technologies, conventional normally open hydraulic control sleeves mainly rely on the elastic return function of springs to keep the sleeve in the open state when the hydraulic pressure is not applied, allowing the corresponding oil and gas reservoir fluid to enter the production tubing. When it is necessary to close, the spring is compressed by hydraulic drive, causing the sleeve to move to the closed position. However, the spring of the traditional sleeve is directly exposed to the downhole liquid medium (such as acidic fluids containing hydrogen sulfide and carbon dioxide or high-salinity brine). Long-term contact with corrosive media will cause the spring material performance to degrade or even break and fail. Sand, mud, or scale in the wellbore can easily accumulate in the spring's active area, causing the sleeve to jam and affecting the reliability of the opening and closing action. During the opening and closing of the sleeve, the change in the volume of the spring chamber will cause sudden changes in internal pressure. Existing technologies do not have an effective pressure balancing structure, which can easily lead to damage to the sealing ring or hydraulic oil leakage, or even failure of the sleeve action due to pressure difference. Therefore, it is necessary to propose a solution to this technical problem. Utility Model Content

[0003] (a) Technical problems to be solved

[0004] To address the shortcomings of existing technologies, this utility model provides a normally open, sealed spring chamber hydraulically controlled sliding sleeve.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, this utility model provides the following technical solution: a normally open sealed spring chamber hydraulically controlled sliding sleeve, comprising an upper connector, a liquid cylinder, an outer tube, a pressure transmitting ring, a spring protective tube, a spring sleeve, an adjusting spring, and a lower connector. The upper connector is threadedly connected to the liquid cylinder, and a perfluoroether rubber sealing ring is provided at the connection. Two pistons are inserted inside the liquid cylinder, and the pistons are engaged in the grooves of the pressure transmitting ring. The liquid cylinder is threadedly connected to the outer tube, and a sealing ring is provided at the connection. The outer tube is threadedly connected to the spring sleeve, and a sliding sleeve is inserted inside it. The sliding sleeve is threadedly connected to the spring protective tube, and one end of the spring protective tube is inserted into the spring sleeve, containing... A spring push rod is included. The spring sleeve is threadedly connected to the lower connector, forming a sealed chamber filled with hydraulic oil and encapsulating an adjusting spring. The adjusting spring sleeve is located outside the lower connector. A spring retaining ring is provided inside the spring sleeve. The two ends of the adjusting spring abut against the spring retaining ring and the inner wall of the spring sleeve, respectively. Three balance plugs are installed on the side wall of the lower connector. The balance plugs are connected to the inner cavity of the sliding sleeve, and the bottom is sealed with hydraulic oil through a plug. A pressure sensor is integrated into the hydraulic oil chamber of the lower connector. A wireless module is embedded in the outer wall of the spring sleeve and connected to the pressure sensor through a waterproof cable. A pressure relief valve is installed on the side wall of the hydraulic cylinder.

[0007] Furthermore, the present invention is improved in that the adjusting spring is made of a nickel-based high-temperature alloy and its surface is coated with a polytetrafluoroethylene anti-corrosion coating.

[0008] Furthermore, the present invention is improved in that the pressure relief valve is a two-stage spring preloaded safety valve.

[0009] Furthermore, the present invention is improved in that the pressure sensor is located in the middle of the hydraulic oil chamber of the lower connector, parallel to the flow channel of the balance plug.

[0010] Furthermore, the present invention is improved in that the power supply system of the wireless module is a high-temperature resistant lithium battery pack, which is encapsulated in an explosion-proof chamber within the spring sleeve cavity.

[0011] Furthermore, the present invention is improved in that the wireless module supports the LoRa communication protocol, operates at a frequency of 433MHz, and has a maximum transmission depth of 5000 meters.

[0012] Furthermore, an improvement of this invention is that the outer surface of the pressure relief valve is coated with a tungsten carbide wear-resistant coating.

[0013] (III) Beneficial Effects

[0014] Compared with the prior art, this utility model provides a normally open sealed spring chamber hydraulically controlled sliding sleeve, which has the following advantages:

[0015] This normally open sealed spring chamber hydraulic control sleeve completely encapsulates the adjusting spring between the spring sleeve and the lower connector in a sealed chamber filled with hydraulic oil. This isolates the spring from direct contact with corrosive downhole liquids such as H2S, CO2, and high-mineralized brine, preventing spring corrosion, scaling, and performance degradation, and extending its service life. By connecting the balance plug and the inner cavity of the sliding sleeve, the pressure difference between the inside and outside of the spring chamber is automatically adjusted during the opening and closing of the sliding sleeve, eliminating the risk of hydraulic shock or negative pressure caused by volume changes, avoiding damage to the sealing ring or jamming of the sliding sleeve. An additional backup balance channel and multi-stage pressure relief valves are added. When the main balance plug is blocked or the system is overpressured, the backup channel is automatically activated, and the pressure relief valves release pressure at stages of 25MPa and 30MPa, effectively preventing structural overload and improving system fault tolerance. An integrated piezoresistive pressure sensor and low-power LoRa wireless module can monitor hydraulic oil pressure changes in real time and upload data to the ground system via the 433MHz frequency band, with a maximum transmission depth of 5000 meters. Operators do not need to rely on indirect judgment and can directly obtain the sliding sleeve status through the remote monitoring platform, reducing wellhead commissioning time and the frequency of manual intervention, thus improving operational efficiency. Attached Figure Description

[0016] Figure 1 This is a front view schematic diagram of the structure of this utility model;

[0017] Figure 2 This is a top view of the pressure balance structure of this utility model;

[0018] Figure 3 This utility model Figure 1 A front view of the enlarged structure of the medium pressure relief valve;

[0019] Figure 4 This utility model Figure 1 A magnified front view of the middle spring sleeve.

[0020] In the diagram: 1. Upper connector; 2. Hydraulic cylinder; 3. Piston; 4. Outer tube; 5. Pressure transmission ring; 6. Sliding sleeve; 7. Spring protective tube; 8. Spring sleeve; 9. Spring push rod; 10. Spring retaining ring; 11. Adjusting spring; 12. Lower connector; 13. Balance plug; 14. Block; 15. Pressure sensor; 16. Wireless module; 17. Pressure relief valve. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] Please see Figure 1-4 This utility model is a normally open sealed spring chamber hydraulic control sliding sleeve, including an upper connector 1, a hydraulic cylinder 2, an outer tube 4, a pressure transmitting ring 5, a spring protective tube 7, a spring sleeve 8, an adjusting spring 11, and a lower connector 12. The upper connector 1 is threadedly connected to the hydraulic cylinder 2, and a perfluoroether rubber sealing ring is provided at the connection. Two pistons 3 are inserted inside the hydraulic cylinder 2, and the pistons 3 are engaged in the grooves of the pressure transmitting ring 5. The hydraulic cylinder 2 is threadedly connected to the outer tube 4, and a sealing ring is provided at the connection. The outer tube 4 is threadedly connected to the spring sleeve 8, and a sliding sleeve 6 is inserted inside. The sliding sleeve 6 is threadedly connected to the spring protective tube 7. One end of the spring protective tube 7 is inserted into the spring sleeve 8, and a spring push rod 9 is accommodated inside. The spring sleeve 8 is threadedly connected to the lower connector, forming a sealed chamber filled with hydraulic oil and encapsulating the adjusting spring 11. 1. The adjusting spring 11 sleeve 8 is located outside the lower connector 12. A spring retaining ring 10 is provided inside the spring sleeve 8. The two ends of the adjusting spring 11 abut against the spring retaining ring 10 and the inner wall of the spring sleeve 8, respectively. Three balance plugs 13 are installed on the side wall of the lower connector. The balance plugs 13 are connected to the inner cavity of the sliding sleeve 6, and the bottom is sealed with hydraulic oil via a plug 14. A pressure sensor 15 is integrated into the hydraulic oil chamber of the lower connector 12. A wireless module 16 is embedded in the outer wall of the spring sleeve 8 and connected to the pressure sensor 15 via a waterproof cable. A pressure relief valve 17 is installed on the side wall of the hydraulic cylinder 2. In this embodiment, during wellhead pressurization, hydraulic oil enters the hydraulic cylinder 2 through the pressure transmission pipeline, pushing the piston 3 and pressure transmission ring 5 forward, causing the sliding sleeve 6 to compress the adjusting spring 11 until the circulation hole of the sliding sleeve 6 and the circulation hole of the outer pipe 4 are misaligned and sealed. The pressure generated by the change in the volume of the spring chamber is dynamically balanced by the balance plugs 13, and the pressure sensor 15 monitors the pressure value in real time and transmits it to the surface.

[0023] When the wellhead oil pressure is released, the adjusting spring 11 elastically releases, pushing the sliding sleeve 6 to reset, aligning the circulation hole of the sliding sleeve with the circulation hole of the outer tube, and opening the production channel. The wireless module 16 transmits a pressure drop signal to the control system to confirm the sliding sleeve status. If the hydraulic system overpressure is greater than 25MPa, the first-stage pressure relief valve 17 on the side wall of the cylinder 2 automatically opens to release pressure; if the pressure continues to rise to 30MPa, the second-stage valve is activated, ensuring safety with a dual protection structure. The adjusting spring 11 is in its naturally extended state, and its elastic force pushes the spring retaining ring 10, the spring push rod 9, and the sliding sleeve 6 backward. The circulation hole of the sliding sleeve 6 aligns with the circulation hole of the outer tube 4, forming an oil and gas production channel, allowing fluid from the corresponding oil and gas layer to pass through. The balance plug 13 is connected to the inner cavity of the sliding sleeve through a flow channel, maintaining a dynamic balance between the spring chamber and the external pressure.

[0024] High-pressure hydraulic oil is injected into the hydraulic control line, and the hydraulic oil enters the cylinder 2 through the pressure transmission line. The hydraulic pressure pushes the two pistons 3 forward, and the pistons 3 drive the pressure transmission ring 5, the sliding sleeve 6, and the spring guard tube 7 to move forward as a whole. The forward movement of the sliding sleeve 6 compresses the adjusting spring 11, reducing the volume of the spring chamber and increasing the hydraulic oil pressure. When the sliding sleeve 6 moves to its limit position, its circulation hole is completely misaligned with the circulation hole of the outer tube 4, the production channel is closed, and production in the corresponding oil and gas layer is stopped. The pressure sensor 15 monitors the hydraulic oil pressure changes in real time and transmits the shutdown status signal to the ground control system via the wireless module 16.

[0025] When the wellhead pressure is stopped and the hydraulic line pressure is released, the elastic restoring force of the adjusting spring 11 pushes the spring retaining ring 10, spring push rod 9, and sliding sleeve 6 to move in the opposite direction. The circulation hole of the sliding sleeve 6 realigns with the circulation hole of the outer tube 4, restoring the production channel and allowing oil and gas flow. When the volume of the spring chamber increases, the balance plug 13 draws in external liquid through the flow channel to balance the internal pressure and prevent negative pressure from causing seal failure.

[0026] The adjusting spring 11 is completely enclosed in a sealed chamber formed by the spring sleeve 8 and the lower connector 12, filled with hydraulic oil and sealed by the plug 14. This prevents downhole fluids such as brine and acidic media from contacting the spring, thus preventing corrosion and scaling. When the sliding sleeve opens and closes, the change in the volume of the spring chamber causes internal pressure fluctuations. The balance plug 13, connected to the inner cavity of the sliding sleeve through a flow channel, dynamically draws in or discharges liquid, maintaining pressure balance inside and outside the chamber. This prevents damage to the sealing ring or jamming of the sliding sleeve due to sudden pressure changes.

[0027] Pressure sensor 15 is integrated in the middle of the hydraulic oil chamber of the lower connector 12 to monitor changes in hydraulic oil pressure in real time. Wireless module 16 uses the LoRa protocol to upload pressure data to the ground system for remote monitoring of the sliding sleeve status (such as closing pressure peaks and opening pressure release rates). When the hydraulic system is unexpectedly overpressurized (e.g., >25MPa), the first-stage spring-preloaded safety valve opens to release pressure; if the pressure continues to rise to 30MPa, the second-stage valve activates, providing dual protection against structural overload.

[0028] To address the problem that traditional springs are susceptible to corrosion from high temperatures and corrosive media (such as H2S and CO2) in wells, leading to elastic failure, the adjusting spring 11 is made of a nickel-based high-temperature alloy and coated with a polytetrafluoroethylene anti-corrosion coating, increasing its temperature resistance to 600℃. This makes it suitable for high-temperature environments in deep wells, and the coating isolates corrosive liquids, extending the spring's lifespan.

[0029] To address the issue of structural damage caused by overpressure in a single pressure relief valve, the pressure relief valve 17 is a two-stage spring preloaded safety valve, with pressures set at 25MPa (first stage) and 30MPa (second stage) respectively, releasing pressure step by step to prevent instantaneous overpressure in the hydraulic system.

[0030] To address the potential impact of pressure sensor 15 positional deviation on monitoring accuracy, the pressure sensor 15 is located in the middle of the hydraulic oil chamber of the lower connector, parallel to the flow channel of the balance plug 13. It directly monitors the dynamic pressure of the hydraulic oil, accurately reflects the opening and closing status of the sliding sleeve, and the parallel layout avoids flow channel interference, thus improving data reliability.

[0031] The harsh underground environment places high demands on the stability of the power supply system for the wireless module. The power supply system for the wireless module 16 is a high-temperature resistant lithium battery pack, which is encapsulated in an explosion-proof chamber within the inner cavity of the spring sleeve 8. The lithium battery pack can withstand temperatures up to 150°C. The explosion-proof chamber isolates the underground vibration and liquid intrusion, ensuring continuous power supply to the wireless module under extreme working conditions.

[0032] To address the limitations of traditional communication protocols, which have short transmission distances and struggle to cover deep well applications, the wireless module 16 supports the LoRa communication protocol. It operates at a frequency of 433MHz and has a maximum transmission depth of 5000 meters. The Low Power Wide Area Network (LPWAN) technology is adapted to the long-distance communication needs underground, and the 433MHz band has strong penetration, ensuring stable signal transmission.

[0033] To address the issue of pressure relief valve 17 being prone to wear due to long-term fluid erosion, the outer surface of pressure relief valve 17 is coated with a tungsten carbide wear-resistant coating. The tungsten carbide has a hardness ≥2000HV, which significantly improves the valve body's resistance to abrasive wear, extends the valve's service life, and reduces maintenance frequency.

[0034] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A normally open closed spring chamber hydraulic control sliding sleeve, comprising an upper joint (1), a hydraulic cylinder (2), an outer tube (4), a pressure transmission ring (5), a spring protection tube (7), a spring sleeve (8), an adjusting spring (11) and a lower joint (12), characterized in that, The upper joint (1) is connected with the liquid cylinder (2) by thread, and a perfluoroether rubber sealing ring is arranged at the connection. The liquid cylinder (2) is internally inserted with two pistons (3), the pistons (3) are clamped into the clamping grooves of the pressure transmission ring (5), the liquid cylinder (2) is connected with the outer pipe (4) by thread, the outer pipe (4) is connected with the spring sleeve (8) by thread, and the sliding sleeve (6) is internally inserted. The sliding sleeve (6) is connected with the spring protection pipe (7) by thread, one end of the spring protection pipe (7) is inserted into the spring sleeve (8), and the spring push rod (9) is accommodated in the spring protection pipe (7). The spring sleeve (8) is connected with the lower joint (12) by thread, and a closed cavity is formed in the spring sleeve (8). The cavity is filled with hydraulic oil, and the adjusting spring (11) is packaged. The adjusting spring (11) is arranged outside the lower joint. The spring sleeve (8) is provided with a spring stop ring (10) in the inner portion. The adjusting spring (11) is respectively abutted against the spring stop ring (10) and the inner wall of the spring sleeve (8) at two ends. Three balance plugs (13) are arranged on the side wall of the lower joint. The balance plugs (13) are communicated with the inner cavity of the sliding sleeve (6), and the bottom is sealed by the plug (14). The pressure sensor (15) is integrated in the hydraulic oil cavity of the lower joint (12). The spring sleeve (8) is embedded with the wireless module (16) on the outer wall, and the pressure sensor (15) is connected with the wireless module (16) through a waterproof cable. The liquid cylinder (2) is provided with the pressure release valve (17) on the side wall.

2. The normally open closed spring chamber chamber hydraulically controlled sliding sleeve according to claim 1, characterized in that, The adjusting spring (11) is made of nickel-based high-temperature alloy, and the surface is coated with a polytetrafluoroethylene corrosion-resistant coating.

3. The normally open closed spring chamber chamber hydraulic control sliding sleeve according to claim 1, characterized in that, The pressure release valve (17) is a two-stage spring pre-tightening safety valve.

4. The normally open closed spring chamber chamber hydraulically controlled sliding sleeve according to claim 1, characterized in that, The pressure sensor (15) is located in the middle of the lower joint hydraulic oil cavity and is parallel to the flow channel of the balance plug (13).

5. The normally open closed spring chamber chamber hydraulically controlled sliding sleeve according to claim 1, characterized in that, The power supply system of the wireless module (16) is a high-temperature-resistant lithium battery pack, which is packaged in the explosion-proof cabin in the inner cavity of the spring sleeve (8).

6. The normally open closed spring chamber chamber hydraulically controlled sliding sleeve according to claim 1, characterized in that, The wireless module (16) supports the LoRa communication protocol, and the working frequency is 433MHz, and the maximum transmission depth is 5000m.

7. The normally open closed spring chamber chamber hydraulically controlled sliding sleeve according to claim 1, characterized in that, The outer surface of the pressure release valve (17) is coated with a tungsten carbide wear-resistant coating.

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