Hydraulic control sliding sleeve with closed spring cavity

Abstract

The utility model relates to the technical field of oil field downhole tools, in particular to a closed spring cavity hydraulic control sliding sleeve which comprises a sliding sleeve mechanism and a pressure balance mechanism, the sliding sleeve mechanism comprises an upper connector, a hydraulic cylinder, an outer pipe, a spring sleeve and a lower connector which are sequentially connected in a threaded mode from top to bottom, a piston is arranged in the hydraulic cylinder, and the sliding sleeve and a spring protection pipe are inserted into the outer pipe. The sliding sleeve is in threaded connection with the spring protection pipe, the piston is in linkage with the sliding sleeve through the pressure transmission ring, the pressure balance mechanism comprises a balance plug, a spring push rod and a spring, and when a circulation channel needs to be opened, hydraulic oil pushes the piston to drive the sliding sleeve to move forwards, so that a circulation hole in the sliding sleeve coincides with a circulation hole in the outer pipe; when closing is needed, elastic potential energy of the spring is released to push the sliding sleeve to move back, and the circulating hole in the sliding sleeve and the circulating hole in the outer pipe are sealed. Through the design, the operation process is simplified, and the working efficiency is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to oilfield downhole tool technical field, concretely is closed spring chamber hydraulic control sliding sleeve. BACKGROUND

[0002] In the oil and gas field completion operation, the hydraulic control sliding sleeve is widely used for the temporary guide control of the production string and the casing annulus. The conventional hydraulic control sliding sleeve realizes pressure connection through the hydraulic drive sliding sleeve opening, and realizes the sliding sleeve closing by relying on the reset spring. The core function is to provide an emergency circulation channel (such as well killing, well washing, chemical injection, etc.) for the oil well after the packer closes the annulus, and to avoid high-cost operation caused by frequent pipe column lifting. In recent years, with the large-scale development of high-angle directional wells and horizontal wells, higher requirements are put forward for the reliability, maintenance-free and adaptability of the hydraulic control sliding sleeve in complex working conditions.

[0003] However, the prior art has the following significant defects:

[0004] Spring performance degradation problem: the reset spring of the conventional hydraulic control sliding sleeve is directly exposed to the wellbore fluid, and long-term contact with corrosive media (such as H2S, CO2, and high salinity formation water) will cause spring material corrosion, stress relaxation, and even rupture. For example, in the operation of a certain oilfield horizontal well, the spring cannot close the sliding sleeve due to sulfide stress corrosion, causing well control risk.

[0005] Risk of fouling and blocking: the spring movable chamber (such as the gap between the sliding sleeve inner wall and the spring) is easily invaded by solid particles (such as mud residue and fracturing sand) in the well fluid, forming structural fouling and causing spring compression / rebound path obstruction. Statistics show that more than 30% of the hydraulic control sliding sleeve failure cases are directly related to spring chamber fouling.

[0006] High temperature and high pressure environment limitation: in deep wells (>4000m) or high temperature reservoirs (>150℃), the change of well fluid viscosity and thermal expansion effect will increase the spring movement resistance, further reducing the sliding sleeve action accuracy. INVENTION CONTENTS

[0007] (I) Technical problem solved

[0008] In view of the deficiencies of the prior art, the utility model provides a closed spring chamber hydraulic control sliding sleeve.

[0009] (II) Technical scheme

[0010] To achieve the above object, the utility model provides the following technical scheme: the utility model discloses airtight spring chamber hydraulic control sliding sleeve, including sliding sleeve mechanism and pressure balance mechanism, the sliding sleeve mechanism includes by from top to bottom sequentially threaded connection's upper joint, liquid cylinder, outer tube, spring cover and lower joint, be provided with piston in the liquid cylinder, the outer tube inserts and has the spring protection tube in the sliding sleeve, the sliding sleeve is connected through the thread with the spring protection tube, the piston is linked with the sliding sleeve through the pressure transmission ring,

[0011] The pressure balance mechanism includes a balance plug disposed in the lower joint and a spring push rod connected to the spring cover, and the spring cover has a spring compressed by the spring push rod.

[0012] The spring cover and the lower joint form airtight hydraulic chamber.

[0013] Preferably, the piston is a symmetrical double-piston structure, and the piston is clamped with an annular clamping groove in the pressure transmission ring.

[0014] Further preferably, the balance plug includes at least three radially arranged plungers, the outer side of which is in communication with the hydraulic chamber, and the inner side of which is in communication with the sliding sleeve flow channel.

[0015] Again preferably, the spring is a pre-compressed coil spring, and the two ends of the spring are limited by spring stop rings and a spring cover, respectively.

[0016] Preferably, the lower joint is provided with an injection hole, the injection hole is in communication with the hydraulic chamber, and the injection hole is installed with a plug through a threaded structure.

[0017] Further preferably, the connection between the upper joint, the liquid cylinder, the outer tube, the spring cover and the lower joint is provided with a sealing ring, the connection between the sliding sleeve and the spring protection tube is provided with a sealing ring, and the connection between the plug and the injection hole is provided with a sealing ring.

[0018] (Three) beneficial effects

[0019] Compared with the prior art, the utility model provides airtight spring chamber hydraulic control sliding sleeve, which has the following

[0020] Beneficial effects:

[0021] Improve the stability and reliability of the system

[0022] Symmetrical double-piston structure: the piston adopts symmetrical double-piston design, and is linked with the sliding sleeve through the pressure transmission ring. This design ensures uniform distribution of force, reduces deviation or wear caused by unilateral force, and improves the stability and reliability of the system.

[0023] Pre-compressed coil spring: A pre-compressed coil spring is used, and is limited by spring retaining rings and spring sleeves at both ends. This design ensures the stability and durability of the spring, allowing the sliding sleeve to run smoothly during opening and closing.

[0024] Internal pressure balance is achieved, improving safety

[0025] Balancing plug design: The balancing plug includes at least three radially arranged plungers, the outer side of which communicates with the hydraulic chamber, and the inner side of which communicates with the sliding sleeve flow passage. When the pressure in the hydraulic chamber changes, the balancing plug can automatically adjust the internal and external pressure difference, maintain the internal pressure balance of the system, prevent leakage or damage caused by the pressure difference, and improve the safety of the equipment.

[0026] Pressure balance mechanism: During the movement of the sliding sleeve, the spring push rod enters the spring sleeve inner cavity, compresses the spring, and causes the volume of the cavity to change, forming internal pressure. This design ensures that the internal pressure is always in a balanced state during the opening and closing of the circulation channel, avoiding equipment failure caused by pressure fluctuations.

[0027] Simplified operation process, improved work efficiency

[0028] Efficient opening and closing mechanism: The opening and closing of the sliding sleeve can be quickly realized by wellhead injection or release of oil pressure. Specifically, when the circulation channel needs to be opened, the hydraulic oil pushes the piston to drive the sliding sleeve to move forward, so that the circulation hole on the sliding sleeve coincides with the circulation hole on the outer pipe; when it needs to be closed, the spring elastic potential energy is released to push the sliding sleeve to move back, so that the circulation hole on the sliding sleeve is sealed with the circulation hole on the outer pipe. This design simplifies the operation process and improves work efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0029] Fig. 1 It is a schematic diagram of the overall cross-sectional structure of the utility model;

[0030] Fig. 2 It is a pressure balance cross-sectional schematic diagram of the utility model;

[0031] In the figure: 1, upper joint; 2, liquid cylinder; 3, piston; 4, outer pipe; 5, pressure transmission ring; 6, sliding sleeve; 7, spring protection pipe; 8, spring sleeve; 9, spring push rod; 10, spring retaining ring; 11, spring; 12, lower joint; 13, balancing plug; 14, plug. DETAILED DESCRIPTION

[0032] Clearly, the described embodiments are merely a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments in the present utility model, all the other embodiments obtained by the person skilled in the art without creative labor fall within the protection scope of the present utility model.

[0033] Please refer to Figs. 1-2 The utility model discloses a closed spring chamber hydraulic control sliding sleeve, including sliding sleeve 6 mechanism and pressure balance mechanism, the sliding sleeve 6 mechanism includes by from top to bottom screw thread connection's upper joint 1, liquid cylinder 2, outer tube 4, spring cover 8 and lower joint 12, be provided with piston 3 in liquid cylinder 2, the outer tube 4 inserts and has sliding sleeve 6 and spring protection pipe 7 in, sliding sleeve 6 and spring protection pipe 7 are connected through screw thread, piston 3 is linked with sliding sleeve 6 through transmission pressure ring 5;

[0034] The pressure balance mechanism includes a balance plug 13 disposed in the lower joint 12 and a spring push rod 9 connected with the spring cover 8, and the spring cover 8 is provided with a spring 11 compressed by the spring push rod 9.

[0035] The spring cover 8 and the lower joint 12 form a closed hydraulic chamber.

[0036] The closed spring 11 chamber hydraulic control sliding sleeve 6 is mainly used for liquid circulation operation in the oil well, and the opening and closing of the sliding sleeve 6 are realized through hydraulic control. The device is mainly composed of a sliding sleeve 6 mechanism and a pressure balance mechanism, which can reliably operate in a high-pressure environment and maintain internal sealing.

[0037] Sliding sleeve 6 mechanism

[0038] Assembly: from top to bottom, the upper joint 1, the liquid cylinder 2, the outer tube 4, the spring cover 8 and the lower joint 12 are connected by screw thread.

[0039] Piston 3: arranged in the liquid cylinder 2, adopting a symmetrical double-piston structure, linked with the sliding sleeve 6 through the transmission pressure ring 5.

[0040] Sliding sleeve 6 and spring protection pipe 7: the sliding sleeve 6 is inserted into the outer tube 4 and connected with the spring protection pipe 7 by screw thread, forming an integral moving unit.

[0041] Pressure balance mechanism

[0042] Assembly: including a balance plug 13 disposed in the lower joint 12 and a spring push rod 9 connected with the spring cover 8, and the spring cover 8 is provided with a spring 11 compressed by the spring push rod 9.

[0043] Closed hydraulic chamber: a closed hydraulic chamber is formed between the spring cover 8 and the lower joint 12 for storing hydraulic oil and maintaining internal pressure balance.

[0044] Working principle of each preferred technical solution

[0045] Symmetrical double-piston structure

[0046] Working principle: Two pistons 3 are symmetrically arranged in the liquid cylinder 2, and are linked with the sliding sleeve 6 through the transmission ring 5 slot. When external hydraulic pressure is applied, the double pistons move synchronously, ensuring uniform force distribution and improving system stability and reliability.

[0047] Balancing plug 13 design

[0048] Working principle: At least three radially arranged plungers constitute the balancing plug 13, which is in communication with the hydraulic chamber on the outside and the sliding sleeve 6 flow passage on the inside. When the pressure in the hydraulic chamber changes, the balancing plug 13 can automatically adjust the internal and external pressure difference, maintain the internal pressure balance of the system, and prevent leakage.

[0049] Pre-compression coil spring

[0050] Working principle: The pre-compression coil spring is installed in the spring sleeve 8, and the two ends are limited by the spring stop ring 10 and the spring sleeve 8 respectively. When the sliding sleeve 6 needs to reset, the elastic potential energy of the spring 11 is released, pushing the sliding sleeve 6 and other related components to move back, realizing the closure of the circulation channel.

[0051] Injection hole and plug 14

[0052] Working principle: The lower joint 12 is provided with an injection hole, and the plug 14 is installed through a threaded structure. The injection hole is in communication with the hydraulic chamber, facilitating the injection of hydraulic oil or maintenance. The design of the plug 14 ensures the sealing of the injection hole, preventing hydraulic oil leakage.

[0053] Application of sealing ring

[0054] Working principle: Sealing rings are provided at the connections of the upper joint 1, liquid cylinder 2, outer pipe 4, spring sleeve 8, and lower joint 12, as well as the connections of the sliding sleeve 6 and spring guard pipe 7, and the plug 14 and injection hole. These sealing rings effectively prevent hydraulic oil leakage, ensuring the sealing performance of the entire system.

[0055] Detailed working process

[0056] Opening the circulation channel

[0057] Step 1: When the circulation operation needs to be opened in the oil well, the wellhead is injected with hydraulic oil, the upper joint 1 is connected to the transmission pipe to introduce hydraulic oil, the hydraulic oil enters the liquid cylinder 2 of the hydraulic control sliding sleeve 6 through the transmission pipe, and internal pressure is formed.

[0058] Step two: the internal pressure pushes the symmetrical double piston, the piston 3 drives the pressure transmission ring 5, the sliding sleeve 6, the spring protection pipe 7, the spring push rod 9 and the spring stop ring 10 to move forward, and the pre-compression spiral spring is compressed.

[0059] Step three: when the spring protection pipe 7 moves to the limit of the spring sleeve 8, the overall movement stops.

[0060] Pressure balance

[0061] Step one: during the opening of the circulation channel, the spring push rod 9 enters the inner cavity of the spring sleeve 8, the compression spring 11 is compressed, the space volume in the cavity changes, and the internal pressure is formed.

[0062] Step two: the internal pressure pushes the balance plug 13, the other side of the balance plug 13 is communicated with the inner cavity of the sliding sleeve 6, so that the internal pressure reaches a balanced state, and leakage or damage caused by pressure difference is prevented.

[0063] Close the circulation channel

[0064] Step one: the wellhead releases the oil pressure, the elastic potential energy of the pre-compression spiral spring is released, and the spring stop ring 10, the spring push rod 9, the sliding sleeve 6, the spring protection pipe 7, the pressure transmission ring 5 and the piston 3 are pushed to move reversely.

[0065] Step two: when the pressure transmission ring 5 moves to be attached to the liquid cylinder 2, the overall movement stops.

[0066] Pressure balance again

[0067] Step one: during the closing of the circulation channel, the space volume in the cavity changes in the elastic release of the spring 11, and the internal pressure is formed.

[0068] Step two: the internal pressure sucks the balance plug 13, the other side of the balance plug 13 is communicated with the inner cavity of the sliding sleeve 6, so that the internal pressure reaches a balanced state again.

[0069] Although the embodiments of the utility model have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the utility model, and the scope of the utility model is defined by the appended claims and their equivalents.

Claims

1. A sealed spring chamber hydraulically controlled sliding sleeve, characterized in that, It includes a sliding sleeve (6) mechanism and a pressure balancing mechanism. The sliding sleeve (6) mechanism includes an upper connector (1), a hydraulic cylinder (2), an outer tube (4), a spring sleeve (8), and a lower connector (12) that are threaded together from top to bottom. A piston (3) is installed inside the hydraulic cylinder (2). The sliding sleeve (6) and the spring protective tube (7) are inserted into the outer tube (4). The sliding sleeve (6) and the spring protective tube (7) are connected by threads. The piston (3) is linked with the sliding sleeve (6) through a pressure transmission ring (5). The pressure balancing mechanism includes a balance plug (13) disposed in the lower connector (12) and a spring push rod (9) connected to the spring sleeve (8). The spring sleeve (8) is provided with a spring (11) compressed by the spring push rod (9). The spring sleeve (8) and the lower connector (12) form a closed hydraulic chamber.

2. The sealed spring chamber hydraulically controlled sliding sleeve according to claim 1, characterized in that, The piston (3) is a symmetrical double piston structure, and the piston (3) is engaged with the annular groove in the pressure transmission ring (5).

3. The sealed spring chamber hydraulically controlled sliding sleeve according to claim 2, characterized in that, The balance plug (13) includes at least three radially arranged plungers, the outer side of which communicates with the hydraulic chamber and the inner side of which communicates with the flow channel of the sliding sleeve (6).

4. The sealed spring chamber hydraulically controlled sliding sleeve according to claim 3, characterized in that, The spring (11) is a pre-compressed helical spring, and the two ends of the spring (11) are respectively limited by spring retaining ring (10) and spring sleeve (8).

5. The sealed spring chamber hydraulically controlled sliding sleeve according to claim 4, characterized in that, The lower connector (12) is provided with an injection hole, which is connected to the hydraulic chamber. The injection hole is plugged (14) by a threaded structure.

6. The sealed spring chamber hydraulically controlled sliding sleeve according to claim 5, characterized in that, A sealing ring is provided at the connection of the upper connector (1), the liquid cylinder (2), the outer tube (4), the spring sleeve (8) and the lower connector (12), a sealing ring is provided at the connection of the sliding sleeve (6) and the spring protective tube (7), and a sealing ring is provided at the connection of the plug (14) and the injection hole.

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