A differential pressure sliding sleeve with repeatable switching

Abstract

The application relates to a differential pressure type sliding sleeve which can be repeatedly opened and closed, comprising a pipe body provided with fracturing holes on the pipe wall, the upper and lower ends of the pipe body are provided with connecting structures for being connected with a pipe column, further comprising an outer sleeve and an inner sleeve, the outer sleeve is slidably sleeved outside the pipe body and blocks the fracturing holes, the outer sleeve and the pipe body are provided with a pressure cavity communicated with the fracturing holes, so that the outer sleeve can be driven by hydraulic pressure to a avoiding position of the fracturing holes, the outer sleeve and the pipe body are further provided with a latch mechanism, so that the outer sleeve can be locked after reaching the avoiding position, the inner sleeve is provided with a matching structure for matching with a tool to be driven by the tool, the inner sleeve has a blocking position for blocking the fracturing holes and an opening position for avoiding the fracturing holes in the moving stroke of the inner sleeve, the inner sleeve and the pipe body are provided with a torque limiting locking mechanism to lock the inner sleeve in the moving path of the inner sleeve, the torque limiting locking mechanism can be unlocked when the unlocking force reaches a certain value, so that the differential pressure type sliding sleeve can be repeatedly opened and closed.

Description

TECHNICAL FIELD

[0001] The present application relates to a differential pressure sliding sleeve which can be repeatedly opened and closed. BACKGROUND

[0002] The differential pressure sliding sleeve is a completion tool developed for the staged completion of horizontal wells, which is usually used in combination with a ball-drop fracturing sliding sleeve, a staged packer, a wellbore isolation valve, a float shoe and other completion tools, and is installed at the toe end of a pipe string. The differential pressure sliding sleeve is opened by hydraulic pressure. Specifically, the differential pressure sliding sleeve is lowered into the well along with the pipe string and the ball-drop fracturing sliding sleeve in a closed state, and before the ball-drop fracturing operation, the differential pressure sliding sleeve is opened by pressurizing the pipe string to provide a channel for pumping a fracturing ball into the ball-drop fracturing sliding sleeve.

[0003] At present, the staged completion technology for horizontal wells has been widely applied in China, which effectively improves the single-well productivity. As for the ball-drop fracturing sliding sleeve, various full-bore differential pressure sliding sleeves which can be repeatedly opened and closed have been developed by major oil and gas fields and research institutes in China, such as the fishing key type, the drillable ball seat type and the self-dissolving ball seat type, which enable the pipe string to form a large bore. However, as for the differential pressure sliding sleeve, the traditional differential pressure sliding sleeve is still used, such as the differential pressure sliding sleeves disclosed in the patent documents with the authorization announcement number CN204782929U, the application publication number CN110080719A and the authorization announcement number CN209212207U. Such sliding sleeves are one-time-use sliding sleeves which cannot be closed after being opened by hydraulic pressure. They have a single function, and the pipe string is always in a state of internal and external communication after being put into production, which cannot implement selective fracturing reconstruction of any layer above the differential pressure sliding sleeve or selective testing of any layer above the differential pressure sliding sleeve. In addition, once a gas well produces a large amount of water, the differential pressure sliding sleeve cannot be quickly closed to achieve water control for gas production. SUMMARY

[0004] The present application aims to provide a differential pressure sliding sleeve which can be repeatedly opened and closed to solve the technical problem that the differential pressure sliding sleeve cannot be repeatedly opened and closed in the prior art.

[0005] To achieve the above-mentioned purpose, the technical scheme of the differential pressure sliding sleeve which can be repeatedly opened and closed provided by the present application is as follows:

[0006] The application discloses a differential pressure sliding sleeve which can be repeatedly opened and closed, comprising a pipe body provided with a fracturing hole on a pipe wall, and a connecting structure at the upper and lower ends of the pipe body for connecting with a pipe string; the differential pressure sliding sleeve further comprises an outer sleeve and an inner sleeve; the outer sleeve is sleeved on the outer wall of the pipe body and blocks the fracturing hole; a pressure cavity is formed between the outer sleeve and the pipe body and communicates with the fracturing hole, so that the outer sleeve can be driven by hydraulic pressure to a avoiding position where the fracturing hole is unblocked; a latch mechanism is further formed between the outer sleeve and the pipe body, so that the outer sleeve can be locked in position after reaching the avoiding position; the inner sleeve is provided with a matching structure for matching with a tool so as to be driven by the tool; the inner sleeve has a blocking position for blocking the fracturing hole and an opening position for avoiding the fracturing hole in a moving stroke of the inner sleeve; a torque limiting mechanism is formed between the inner sleeve and the pipe body, so as to lock the inner sleeve in position at the end of the moving path of the inner sleeve; and the torque limiting mechanism can be unlocked when the unlocking force reaches a certain value.

[0007] The differential pressure sliding sleeve is provided with the outer sleeve; when the fracturing hole of the differential pressure sliding sleeve needs to be opened, the pressure in the pipe string is increased, the outer sleeve is driven to move to the avoiding position under the action of the pressure, the inner cavity of the pipe string is communicated with the outside, and then the fracturing ball can be pumped; when the differential pressure sliding sleeve needs to be repeatedly fractured and reformed on any layer segment above the differential pressure sliding sleeve, or needs to be tested on any layer segment, or when a large amount of water appears in a gas well, a tool can be lowered into the pipe string through a small-size coiled tubing to match with the inner sleeve, so as to drive the inner sleeve to adjust the position of the inner sleeve between the blocking position and the opening position, and the differential pressure sliding sleeve can be repeatedly opened and closed.

[0008] As a further improvement, the pipe body comprises a central pipe and an upper joint, the connecting structure at the upper end of the pipe body is located on the upper joint, the fracturing hole is formed in the central pipe, the upper joint is connected to the central pipe by matching with the inner cavity of the central pipe, and the inner cavity of the outer sleeve comprises a large-diameter section matched with the central pipe and a small-diameter section matched with the upper joint, and the outer sleeve, the upper joint and the central pipe jointly form the pressure cavity.

[0009] The pressure cavity is directly formed by matching the outer sleeve, the upper joint and the central pipe, the upper end surface of the central pipe is utilized, and the corresponding structure does not need to be designed and processed for the central pipe, so that the differential pressure sliding sleeve which can be repeatedly opened and closed is convenient to produce and manufacture.

[0010] As a further improvement, a compression spring is arranged in the pressure cavity, one end of the compression spring abuts against the upper end surface of the central pipe, and the other end abuts against a stepped surface at the transition between the large-diameter section and the small-diameter section of the inner cavity of the outer sleeve; and the torque limiting mechanism for locking the outer sleeve in position for blocking the fracturing hole is formed between the outer sleeve and the pipe body.

[0011] The beneficial effect is that the compression spring drives the outer sleeve to slide faster relative to the center tube, ensuring that the outer sleeve can be reliably and quickly opened, and the pin prevents the outer sleeve from being opened by mistake.

[0012] As a further improvement, the upper joint has a stop structure arranged at a distance from the upper end surface of the center tube to limit the maximum stroke of the upward movement of the outer sleeve.

[0013] The beneficial effect is that the stop structure limits the maximum stroke of the upward movement of the outer sleeve, preventing the sliding distance from being too large when the outer sleeve slides to the escape position, which prevents the latch mechanism from being latched.

[0014] As a further improvement, the outer sleeve is in clearance fit with the center tube, and the gap between them forms a channel connecting the fracturing hole and the pressure chamber, and the upper and lower ends of the outer sleeve are in sealing fit with the upper joint and the center tube respectively.

[0015] The beneficial effect is that the gap between the outer sleeve and the center tube directly encloses the channel connecting the fracturing hole and the pressure chamber, making the repeatable differential pressure sliding sleeve easy to manufacture, and reducing the friction between the outer sleeve and the inner center tube to ensure that the outer sleeve can be opened stably and reliably.

[0016] As a further improvement, the torque limiting locking mechanism between the inner sleeve and the pipe body is composed of a snap spring and a snap spring fitting groove arranged on the pipe body and the inner sleeve respectively, and the groove wall on the side of the inner sleeve in the direction of movement is a inclined groove wall, so that the torque limiting locking mechanism can be unlocked when the unlocking force reaches a certain value.

[0017] The beneficial effect is that the torque limiting locking mechanism with a snap spring and a snap spring fitting groove is simple in structure and easy to obtain materials, making the repeatable differential pressure sliding sleeve easy to manufacture.

[0018] As a further improvement, the fitting structure is a ring groove opened on the inner wall of the inner sleeve, and the ring groove is hooked and fitted with the corresponding tool through the groove wall in the upward and downward direction.

[0019] The beneficial effect is that the ring groove structure is easy to process and manufacture, so the use of the ring groove structure for the fitting structure makes the inner sleeve easy to manufacture, and further makes the repeatable differential pressure sliding sleeve easy to manufacture.

[0020] As a further improvement, the repeatable differential pressure sliding sleeve further comprises a torque limiting locking mechanism capable of locking the position of the inner sleeve at the lower end of its movement path.

[0021] The beneficial effect is that the position of the inner sleeve is limited by the torque limiting locking structure, preventing the inner sleeve from being opened or closed by mistake.

[0022] As a further improvement, the pipe body further comprises an upper joint, the connecting structure at the upper end of the pipe body is located on the upper joint, the upper joint is connected with the inner cavity of the central pipe and is located on the central pipe, and the lower end face of the upper joint limits the position limit of the upward movement of the inner sleeve.

[0023] The beneficial effect is that the upper joint is used to limit the position limit of the inner sleeve, the lower end face of the upper joint is utilized, no limiting structure for limiting the position of the inner sleeve is designed in the pipe body, and the differential pressure sliding sleeve with repeatable opening and closing has the simplest structure.

[0024] As a further improvement, the pipe body further comprises a lower joint, the connecting structure at the lower end of the pipe body is located on the lower joint, the lower joint is connected with the inner cavity of the central pipe and is located on the central pipe, and the upper end face of the lower joint limits the position limit of the downward movement of the inner sleeve.

[0025] The beneficial effect is that the upper joint and the lower joint are used to limit the position limit of the inner sleeve, the lower end face of the upper joint and the upper end face of the lower joint are utilized, no limiting structure for limiting the position of the inner sleeve is designed in the pipe body, the position of the inner sleeve is reliably adjusted, and the differential pressure sliding sleeve with repeatable opening and closing has the simplest structure. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a structure schematic view of the differential pressure sliding sleeve with repeatable opening and closing in the embodiment 1 of the present application;

[0027] Figure 2 It is a structure schematic view of the differential pressure sliding sleeve with repeatable opening and closing in the embodiment 1 of the present application; Figure 1 It is a partial enlarged view of A in the embodiment 1 of the present application;

[0028] Figure 3 It is a structure schematic view of the differential pressure sliding sleeve with repeatable opening and closing in the embodiment 1 of the present application; Figure 1 It is a partial enlarged view of B in the embodiment 1 of the present application;

[0029] Figure 4 It is a structure schematic view of the differential pressure sliding sleeve with repeatable opening and closing in the embodiment 1 of the present application;

[0030] Figure 5 It is a structure schematic view of the differential pressure sliding sleeve with repeatable opening and closing in the embodiment 1 of the present application;

[0031] Figure 6 It is a structure schematic view of the differential pressure sliding sleeve with repeatable opening and closing in the embodiment 1 of the present application;

[0032] Figure 7 It is a structure schematic view of the differential pressure sliding sleeve with repeatable opening and closing in the embodiment 1 of the present application;

[0033] Explanation of reference signs:

[0034] 1, center tube; 2, upper joint; 3, lower joint; 4, fracturing hole; 5, outer sleeve; 6, sealing ring; 7, compression spring; 8, retreat stop ring; 9, retreat stop tooth; 10, inner sleeve; 11, snap spring; 12, upper snap spring groove; 13, lower snap spring groove; 14, upper ring groove; 15, lower ring groove; 16, upper sealing ring; 17, lower sealing ring; 18, shear pin. DETAILED DESCRIPTION

[0035] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application, i.e., the described embodiments are only some of the embodiments of the present application, but not all the embodiments. The components of the embodiments of the present application generally described and shown in the drawings herein can be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without making creative efforts fall within the scope of the present application.

[0037] It should be noted that the relational terms such as "first" and "second" and the like are used only to distinguish one entity or operation from another, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus including a series of elements includes not only those elements, but also other elements not explicitly listed or inherent to such process, method, article or apparatus. Without more limitations, the element defined by the phrase "including a" does not exclude other elements in the process, method.

[0038] In the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" that can appear should be understood in a broad sense, for example, can be fixed connection, can be detachable connection, or integral connection; can be mechanical connection, can be electrical connection; can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the term "provided with" should be interpreted broadly. For example, the object "provided with" can be a part of the main body, or it can be separately arranged from the main body and connected to the main body. This connection can be a detachable connection or a non-detachable connection. Those skilled in the art can understand the specific meaning of the above terms in this invention through specific circumstances.

[0040] The present invention will be further described in detail below with reference to the embodiments.

[0041] Specific embodiment 1 of the repeatable switching differential pressure sliding sleeve provided by the present invention:

[0042] like Figure 1 As shown, the repeatable differential pressure sleeve includes a tube body. Specifically, the tube body includes a central tube 1 and an upper connector 2 and a lower connector 3 connected to the upper and lower ends of the central tube 1, respectively. Both ends of the central tube 1 have internal threads. The upper connector 2 and the lower connector 3 are screwed into the central tube 1 by engaging with the internal threads of the central tube 1. The upper end of the upper connector 2 has an internal thread, and correspondingly, the lower end of the lower connector 3 has an external thread. The internal thread at the upper end of the upper connector 2 and the external thread at the lower end of the lower connector 3 serve as the connecting structure of the tube body, allowing the differential pressure sleeve to be connected in series in the tube column.

[0043] A fracturing hole 4 is provided on the central tube 1, such as Figure 1 As shown, the outer sleeve 5 is provided on the outer sleeve of the tube body. In the initial state, the outer sleeve 5 seals the fracturing hole 4. Specifically, the inner cavity of the outer sleeve 5 is divided into a large-diameter section and a small-diameter section. The large-diameter section fits with the outer circumferential surface of the central tube 1, and the small-diameter section fits with the outer circumferential surface of the upper connector 2. Since the outer diameter of the section of the upper connector 2 that fits with the central tube 1 is smaller than the outer diameter of the central tube 1, the upper end face of the outer sleeve 5 fits with the upper connector 2 and the central tube 3 to form a pressure cavity. In this embodiment, the outer sleeve 5 and the central tube 1 are in a clearance fit. The annular space between the outer sleeve 5 and the central tube 1 connects the pressure cavity with the fracturing hole 4. At the same time, in order to achieve the sealing of the sliding sleeve, the upper end and the lower end of the outer sleeve 5 are respectively sealed with the upper connector 2 and the central tube 1 through sealing rings 6. Thus, when it is necessary to open the sliding sleeve, the pressure in the inner cavity of the tube body is increased. The hydraulic pressure in the inner cavity of the tube body increases the pressure in the pressure cavity through the fracturing hole 4 and the annular space between the outer sleeve 5 and the central tube 1. The high pressure drives the outer sleeve 5 to move upward to the clearance position to release the seal on the fracturing hole 4.

[0044] In the embodiment, in order to make the outer sleeve 5 reliably and quickly move to the avoiding position during the opening operation, a compression spring 7 is arranged in the pressure cavity. Specifically, the lower end of the compression spring 7 abuts against the upper end face of the center pipe 1, and the upper end abuts against the stepped face between the large-diameter section and the small-diameter section of the inner cavity of the outer sleeve 1. Meanwhile, the lower end of the outer sleeve 5 is pinned with the center pipe 1 by using a shear pin 18, so as to ensure that the outer sleeve 5 can be stably kept at the position for plugging the fracturing hole 4 before the opening operation. Further, the upper joint 2 is provided with a stop structure, which is a stepped face arranged on the upper joint 2 in the embodiment. By cooperation between the stop structure and the upper end face of the outer sleeve 5, the maximum stroke of the upward movement of the outer sleeve 5 can be limited. In other embodiments, the stop structure can also be a protrusion arranged on the upper joint 2, such as a stop pin, a lug, etc. In addition, in order to ensure that the outer sleeve 5 can be stably kept at the avoiding position after being opened, a latch mechanism is arranged between the outer sleeve 5 and the center pipe 1. Specifically, as shown in Figure 2 , the latch mechanism includes a stop ring 8 arranged on the outer sleeve 5 and a stop tooth 9 arranged on the center pipe 1. When the outer sleeve 5 moves to the avoiding position, the stop tooth 9 cooperates with the stop ring 8 to lock the outer sleeve 5 at the avoiding position.

[0045] In order to realize the repeated opening and closing, an inner sleeve 10 is arranged in the pipe body. Specifically, as shown in Figure 1 , the inner sleeve 10 is slidingly arranged in the center pipe 1, and is provided with a cooperation structure for cooperating with a tool, so that the inner sleeve 10 can be driven to move up and down by the tool. In the initial state, the inner sleeve 10 is located below the fracturing hole 4 and is at the opening position. When it is needed to close the fracturing hole 4 by using the inner sleeve 10, the inner sleeve 10 is lifted by cooperating the tool with the cooperation structure. In order to keep the position of the inner sleeve 10, a torque limiting and locking mechanism is arranged between the inner sleeve 10 and the center pipe 1. Specifically, the torque limiting and locking mechanism includes a circlip 11 arranged on the inner sleeve 10 and an upper circlip groove 12 arranged on the upper end of the center pipe 1 as shown in Figure 2 . When the inner sleeve 10 moves up to the plugging position, the circlip 11 cooperates with the upper circlip groove 12 to lock the position of the inner sleeve 10. The lower groove wall of the upper circlip groove 12 is inclined, so that the torque limiting and locking mechanism can be unlocked. When the downward pushing force applied to the inner sleeve 10 reaches a certain value, the torque limiting and locking mechanism can be unlocked, so that the inner sleeve 10 can be driven to move downward to the opening position. In the embodiment, in order to ensure that the inner sleeve 10 can be stably kept at the opening position, a lower circlip groove 13 is arranged at the lower end of the center pipe 1. When the inner sleeve 10 is at the opening position, the circlip 11 cooperates with the lower circlip groove 13 to lock the inner sleeve 10 at the opening position. The upper groove wall of the lower circlip groove 13 is inclined, so that the torque limiting and locking mechanism formed by the cooperation between the circlip 11 and the lower circlip groove 13 can be unlocked.

[0046] In this embodiment, the tool for driving the inner sleeve 10 is the bidirectional starting type sliding sleeve switch tool disclosed in the patent document with the authorized publication number CN203362115U. Correspondingly, as shown in Figure 3 The matching structure is an upper ring groove 14 and a lower ring groove 15 formed on the upper end and lower end of the inner wall of the inner sleeve 10. The included angle between the upper groove wall and the groove bottom of the upper ring groove 14 is 90°, and the included angle between the lower groove wall and the groove bottom is 150°, so that the tool can be hooked and matched with the upper groove wall of the upper ring groove 14 when moving upward, and can slide out of the upper ring groove 14 under the guidance of the lower groove wall when moving downward. Opposite to the upper ring groove 14, the included angle between the upper groove wall and the groove bottom of the lower ring groove 15 is 150°, and the included angle between the lower groove wall and the groove bottom is 90°.

[0047] In order to seal the fracturing hole 4, the outer wall of the inner sleeve 10 is further provided with an upper sealing ring 16 and a lower sealing ring 17. After the inner sleeve 10 moves to the plugging position, the upper sealing ring 16 and the lower sealing ring 17 are located on the upper and lower sides of the fracturing hole 4. When the inner sleeve 10 is in the open position, the upper sealing ring 16 and the lower sealing ring 17 are located on the upper and lower sides of the fracturing hole 4, respectively.

[0048] In specific use, the differential pressure type sliding sleeve capable of being repeatedly switched in the present application is used in cooperation with the ball fracturing sliding sleeve capable of achieving full bore. Specifically, in the initial state, as shown in Figure 4 The outer sleeve 5 is in the position of plugging the fracturing hole 4, and the inner sleeve 10 is in the open position. When it is necessary to pump the fracturing ball, the pressure in the pipe string is increased, so that the pressure in the pressure chamber is increased, and the outer sleeve 5 is driven to move upward to the avoiding position, as shown in Figure 5 The opening of the sliding sleeve is achieved, and then the pumping operation of the fracturing ball can be performed. When it is necessary to close the sliding sleeve, since the ball fracturing sliding sleeve can achieve full bore, a tool matched with the inner sleeve 10 can be lowered into the pipe string through the small size coiled tubing, and the inner sleeve 10 is pulled to the plugging position by the tool exerting force on the inner sleeve 10 to overcome the cooperation between the snap spring 11 and the lower snap spring groove 13, as shown in Figure 6 The snap spring 11 cooperates with the upper snap spring groove 12, and the lower end surface of the upper joint 2 limits the limit stroke of the upward movement of the inner sleeve 10. When it is necessary to open the sliding sleeve again, the tool cooperates with the lower groove 15 to push the inner sleeve 10 to the open position, as shown in Figure 7 The upper end surface of the lower joint 3 limits the limit stroke of the downward movement of the inner sleeve 10.

[0049] For the up-down direction in the above embodiment, the structure of the sliding sleeve is described only in the vertical state of the sliding sleeve to clarify the movement form of the outer sleeve and the inner sleeve relative to the central pipe.

[0050] The specific embodiment 2 of the repeatable switchable differential pressure sliding sleeve provided by the application is mainly different from the embodiment 1 in that, in the embodiment 1, the upper joint, the outer sleeve and the center pipe cooperate to form the pressure cavity, in the embodiment, the upper end of the center pipe is designed as a structure in which a large-diameter section cooperates with a small-diameter section, the upper end is the small-diameter section, the large-diameter section is below the small-diameter section, the small-diameter section of the inner cavity of the outer sleeve cooperates with the small-diameter section of the center pipe, and the large-diameter section cooperates with the large-diameter section of the center pipe, and the center pipe and the outer sleeve directly form the pressure cavity.

[0051] The specific embodiment 3 of the repeatable switchable differential pressure sliding sleeve provided by the application is mainly different from the embodiment 1 in that, in the embodiment, the snap spring in the torque limiting locking mechanism is arranged on the center pipe, and the snap spring groove is arranged on the inner sleeve, and correspondingly, two snap springs are arranged at the upper and lower ends of the center pipe.

[0052] The specific embodiment 4 of the repeatable switchable differential pressure sliding sleeve provided by the application is mainly different from the embodiment 1 in that, in the embodiment, the torque limiting locking mechanism is a spring steel ball locking mechanism, specifically, a blind hole is formed on the inner sleeve in the radial direction, a steel ball is arranged in the blind hole through a spring, and correspondingly, a matching groove is formed on the wall of the center pipe, before reaching the matching groove, the steel ball is in the blind hole and compresses the spring, when the spring reaches the position aligned with the matching groove, the steel ball partially enters the matching groove under the pushing action of the spring, and the position of the inner sleeve is locked.

[0053] The specific embodiment 5 of the repeatable switchable differential pressure sliding sleeve provided by the application is mainly different from the embodiment 1 in that, in the embodiment, the matching structure for driving the inner sleeve to move upward is the lower end surface of the inner sleeve, and based on this, when the inner sleeve is in the open position, the lower joint is arranged in the interval of the inner sleeve.

[0054] Finally, it should be noted that the above only describes the preferred embodiments of the application and is not used to limit the application, although the application has been described in detail with reference to the foregoing embodiments, for those skilled in the art, the technical solutions recorded in the foregoing embodiments can be modified without creative labor, or some technical features can be replaced equivalently. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A repeatable differential pressure sliding sleeve, comprising a tube body with fracturing holes in its wall, wherein the upper and lower ends of the tube body have connection structures for connecting to a tubular column, characterized in that, The repeatable differential pressure sleeve further includes an outer sleeve and an inner sleeve. The outer sleeve is slidably fitted onto the outside of the tube and seals the fracturing orifice. A torque-limiting locking mechanism is provided between the outer sleeve and the tube body to lock the outer sleeve in the position where it seals the fracturing orifice. The tube body includes a central tube and an upper connector. The fracturing orifice is located on the central tube. The upper connector mates with the inner cavity of the central tube and is connected to the central tube. The inner cavity of the outer sleeve includes a large-diameter section that mates with the central tube and a small-diameter section that mates with the upper connector. The outer sleeve, the upper connector, and the central tube together enclose a pressure chamber communicating with the fracturing orifice. A compression spring is installed within the pressure chamber. One end of the compression spring abuts against the upper end face of the central tube, and the other end abuts against the stepped surface at the transition between the large-diameter and small-diameter sections of the inner cavity of the outer sleeve, causing the outer sleeve to... It can be driven by hydraulic pressure and spring force to a clearance position to release the seal on the fracturing hole; the outer sleeve and the tube body also have a locking mechanism to keep the outer sleeve in the clearance position, the locking mechanism includes a backstop ring on the outer sleeve and a backstop tooth on the central tube; the upper connector has a stop structure spaced apart from the upper end face of the central tube to limit the maximum upward stroke of the outer sleeve; the inner sleeve has a mating structure for cooperating with a tool to be driven by the tool, the inner sleeve has a sealing position to seal the fracturing hole and an opening position to avoid the fracturing hole within its movement stroke, and the inner sleeve and the tube body have a torque limiting locking mechanism that is unlocked after the unlocking force reaches a certain value to lock the inner sleeve in the upper end of its movement path.

2. The repeatable differential pressure sliding sleeve according to claim 1, characterized in that, The connection structure at the upper end of the pipe body is located on the upper connector.

3. The repeatable differential pressure sliding sleeve according to claim 2, characterized in that, The outer sleeve and the central tube are fitted with a clearance, and the gap between them forms a channel connecting the fracturing hole and the pressure chamber. The upper and lower ends of the outer sleeve are respectively sealed to the upper connector and the central tube.

4. The repeatable differential pressure sliding sleeve according to any one of claims 1-3, characterized in that, The torque limiting locking mechanism between the inner sleeve and the tube body consists of a snap ring and a snap ring mating groove respectively provided on the tube body and the inner sleeve. The groove wall of the snap ring mating groove on the side of the inner sleeve's movement direction is an inclined groove wall, so that the torque limiting locking mechanism can be unlocked after the unlocking force reaches a certain value.

5. The repeatable switching differential pressure sliding sleeve according to any one of claims 1-3, characterized in that, The mating structure is an annular groove formed on the inner wall of the inner sleeve, and the annular groove is hooked and mated with the corresponding tool through its groove wall in the vertical direction.

6. The repeatable differential pressure sliding sleeve according to any one of claims 1-3, characterized in that, The repeatable differential pressure sliding sleeve also includes a torque limiting locking mechanism that can lock the inner sleeve at the lower end of its movement path.

7. The repeatable differential pressure sliding sleeve according to claim 1, characterized in that, The tube body includes a central tube and an upper connector. The connecting structure at the upper end of the tube body is located on the upper connector. The fracturing hole is opened on the central tube. The upper connector is connected to the inner cavity of the central tube. The lower end of the upper connector limits the upward movement of the inner sleeve.

8. The repeatable differential pressure sliding sleeve according to claim 7, characterized in that, The tube body also includes a lower connector, and the connecting structure at the lower end of the tube body is located on the lower connector. The lower connector is connected to the inner cavity of the central tube and is fitted onto the central tube. The upper end of the lower connector limits the downward movement of the inner sleeve.

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