Closable differential pressure sleeve

Abstract

The present invention belongs to the technical field of well completion engineering for unconventional oil and gas reservoirs such as petroleum and natural gas, and specifically relates to a closable differential pressure sleeve used in fracturing technology, which aims to solve the problem that when the existing differential pressure sleeve needs to be closed, the sleeve of the structure cannot be closed. The closable differential pressure sleeve includes a body with a sandblasting hole at the bottom, an opening sleeve arranged in the body, and a closing sleeve arranged above the opening sleeve, and the opening sleeve blocks the sandblasting hole; in the first working state, the opening sleeve moves upward, and the opening sleeve and the closing sleeve are locked in the first locking state by the first locking mechanism, and the sandblasting hole is opened; in the second working state, the closing sleeve pushes the opening sleeve to move downward, and the opening sleeve and the closing sleeve are locked in the second locking state by the second locking mechanism, and the sandblasting hole is closed. The sleeve can be closed after opening.

Description

Technical Field

[0001] The invention belongs to the technical field of well completion engineering of unconventional oil and gas reservoirs such as petroleum and natural gas, and in particular relates to a closable differential pressure sliding sleeve used in fracturing technology. Background Art

[0002] The pressure differential opening sliding sleeve currently used, in order to ensure that the sliding sleeve is in a normally open state after the sliding sleeve is opened, the sliding sleeve core is usually locked to the sliding sleeve outer cylinder through a locking mechanism such as a locking ring. This method can keep the sliding sleeve in a normally open state without affecting normal production. However, when the pressure differential sliding sleeve needs to be closed, the sliding sleeve of this structure cannot be closed. Summary of the invention

[0003] The invention provides a closable pressure differential sliding sleeve to alleviate the problem that when the existing pressure differential sliding sleeve needs to be closed, the sliding sleeve of this structure cannot be closed.

[0004] In order to alleviate the above technical problems, the technical solution provided by the present invention is:

[0005] A closable pressure differential sleeve comprises a body with a sandblasting hole at the bottom, an opening sleeve arranged in the body and a closing sleeve arranged above the opening sleeve, wherein the opening sleeve blocks the sandblasting hole; in a first working state, the opening sleeve moves upward, and the opening sleeve and the closing sleeve are locked in a first locking state by a first locking mechanism, at which time the sandblasting hole is opened; in a second working state, the closing sleeve pushes the opening sleeve to move downward, and the opening sleeve and the closing sleeve are locked in a second locking state by a second locking mechanism, at which time the sandblasting hole is closed.

[0006] Furthermore, a first sliding section is provided at the upper part of the opening sleeve, and a gap is provided between the first sliding section and the main body; a second sliding section is provided at the lower part of the closing sleeve, and the second sliding section extends into the gap formed by the first sliding section and the main body; the first sliding section and the second sliding section are slidably connected.

[0007] Furthermore, the first locking mechanism includes a first groove located on the outer end surface of the first sliding section and a first C-shaped locking ring located on the inner end surface of the second sliding section. When the first C-shaped locking ring is restored to its original state and inserted into the first groove, the opening sleeve and the closing sleeve are in a first locking state.

[0008] Furthermore, the opening sleeve is fixed to the body by a first shear pin, and the closing sleeve is fixed to the body by a second shear pin; in the first working state, the first shear pin is sheared off and the opening sleeve moves upward; in the second working state, the second shear pin is sheared off and the closing sleeve pushes the opening sleeve to move downward.

[0009] Furthermore, it also includes an upper joint arranged on the upper part of the main body, the upper joint and the main body are connected through a connecting sleeve, the upper part of the connecting sleeve is located inside the upper joint, and the lower part of the connecting sleeve is located inside the main body.

[0010] Furthermore, the closed differential pressure sleeve drives the closing sleeve to move downward through a closing ball plug; the closing ball plug includes a cylindrical upper ball plug and a lower ball plug provided with a smooth arc surface, the outer diameter of the upper ball plug matches the inner diameter of the upper joint, and the lower ball plug is inserted into the top opening of the closing sleeve.

[0011] Furthermore, the top wall of the connecting sleeve and the lower part of the upper joint form a first annular groove with an opening toward the interior of the upper joint; the second locking mechanism includes a second groove located on the closing ball plug and a second C-type locking ring located in the first annular groove. When the second C-type locking ring is restored to its original state and inserted into the second groove, the opening sleeve, the closing sleeve and the closing ball plug are in a second locking state.

[0012] Furthermore, a liquid outlet is provided at the upper part of the upper joint, and an outer sleeve is provided on the outer part of the upper joint and the main body; in a first working state, the outer sleeve is locked with the main body through a third locking mechanism, and the outer sleeve blocks the liquid outlet; in a second working state, the outer sleeve is unlocked from the main body.

[0013] Furthermore, the third locking mechanism includes a fixed locking block, which has a locked state and an unlocked state, a first opening is provided on the main body, and a third groove is provided on the outer sleeve; when the fixed locking block is in the locked state, the closing sleeve presses the fixed locking block toward the outside so that the fixed locking block passes through the first opening and the third groove at the same time, thereby locking the outer sleeve and the main body; when the fixed locking block is in the unlocked state, the fixed locking block loses the extrusion force of the closing sleeve.

[0014] Furthermore, a first step is provided on the outer periphery of the upper joint, and a second step is provided on the outer periphery of the main body, and the first step and the second step form an installation space; the top of the outer sleeve abuts against the first step, and a telescopic member is provided between the bottom of the outer sleeve and the end face of the second step, and the telescopic member is configured to always have a tendency to drive the outer sleeve to move upward in the installation space.

[0015] The beneficial effects of the present invention are analyzed as follows:

[0016] A closable pressure differential sleeve comprises a body with a sandblasting hole at the bottom, an opening sleeve arranged in the body and a closing sleeve arranged above the opening sleeve, wherein the opening sleeve blocks the sandblasting; in a first working state, the opening sleeve moves upward, and the opening sleeve and the closing sleeve are locked in a first locking state by a first locking mechanism, at which time the sandblasting hole is opened; in a second working state, the closing sleeve pushes the opening sleeve to move downward, and the opening sleeve and the closing sleeve are locked in a second locking state by a second locking mechanism, at which time the sandblasting hole is closed.

[0017] In the first working state, the opening sleeve moves upward and opens the sandblasting hole, and the opening sleeve and the closing sleeve are locked by the first locking mechanism so that the sleeve can remain in the open state; in the second working state, the closing sleeve pushes the opening sleeve to move downward and blocks the sandblasting hole, and the opening sleeve and the closing sleeve are locked by the second locking mechanism so that the sleeve is closed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related technologies, the drawings required for use in the specific embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic diagram of the initial structure of a closable differential pressure sleeve provided in an embodiment of the present invention;

[0020] Figure 2 A schematic diagram of the opening structure of a closable differential pressure sleeve provided in an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of inserting a closing ball plug into a closable differential pressure sleeve provided in an embodiment of the present invention;

[0022] Figure 4 A schematic structural diagram of a closable differential pressure sleeve in a closed state provided by an embodiment of the present invention;

[0023] Figure 5 The sliding sleeve provided in the embodiment of the present invention can provide a schematic diagram of a liquid delivery channel after being closed.

[0024] icon:

[0025] 100-main body; 200-opening sleeve; 300-closing sleeve; 400-first locking mechanism; 500-second locking mechanism; 600-closing ball plug; 700-upper joint; 800-connecting sleeve; 900-outer sleeve; 1000-third locking mechanism; 1100-spring; 1200-first shear pin; 1300-second shear pin; 1400-sealing ring; 1500-lower joint; 210-first sliding section; 310-second sliding section; 410-first groove; 420-first C-type locking ring; 510-second groove; 520-second C-type locking ring; 610-upper ball plug; 620-lower ball plug; 1010-fixed locking block; 710-first step; 110-second step; 001-sandblasting hole; 002-liquid outlet. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described implementation is only a part of the implementation of the present invention, not all of the implementation. Based on the implementation of the present invention, all other implementations obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. Physical quantities in formulas, if not separately marked, should be understood as basic quantities of the base units of the International System of Units, or derived quantities derived from the basic quantities through mathematical operations such as multiplication, division, differentiation or integration.

[0028] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] The pressure differential opening sliding sleeve currently used, in order to ensure that the sliding sleeve is in a normally open state after the sliding sleeve is opened, the sliding sleeve core is usually locked to the sliding sleeve outer cylinder through a locking mechanism such as a locking ring. This method can keep the sliding sleeve in a normally open state without affecting normal production. However, when the pressure differential sliding sleeve needs to be closed, the sliding sleeve of this structure cannot be closed.

[0030] In view of this, the present invention provides a closable pressure differential sleeve, please refer to Figures 1 to 5 The closable differential pressure sleeve comprises a main body 100 with a sandblasting hole 001 at the lower part, an opening sleeve 200 arranged in the main body 100 and a closing sleeve 300 arranged above the opening sleeve 200, and the opening sleeve 200 blocks the sandblasting hole 001; in a first working state, the opening sleeve 200 moves upward, and the opening sleeve 200 and the closing sleeve 300 are locked in a first locking state by a first locking mechanism 400, at which time the sandblasting hole 001 is opened; in a second working state, the closing sleeve 300 pushes the opening sleeve 200 to move downward, and the opening sleeve 200 and the closing sleeve 300 are locked in a second locking state by a second locking mechanism 500, at which time the sandblasting hole 001 is closed.

[0031] In the first working state, the opening sleeve 200 moves upward and opens the sandblasting hole 001, and the opening sleeve 200 and the closing sleeve 300 are locked by the first locking mechanism 400 so that the sleeve can remain in the open state; in the second working state, the closing sleeve 300 pushes the opening sleeve 200 to move downward and blocks the sandblasting hole 001, and the opening sleeve 200 and the closing sleeve 300 are locked by the second locking mechanism 500 so that the sleeve is closed.

[0032] In an optional solution of this embodiment, a first sliding section 210 is disposed on the upper portion of the opening sliding sleeve 200, and a gap is formed between the first sliding section 210 and the body 100; a second sliding section 310 is disposed on the lower portion of the closing sliding sleeve 300, and the second sliding section 310 extends into the gap formed by the first sliding section 210 and the body 100; the first sliding section 210 and the second sliding section 310 are slidably connected. The opening sliding sleeve 200 and the closing sliding sleeve 300 can move independently without interfering with each other.

[0033] In the optional solution of this embodiment, the first locking mechanism 400 includes a first groove 410 located on the outer end surface of the first sliding section 210 and a first C-type locking ring 420 located on the inner end surface of the second sliding section 310. In the first working state, the opening sleeve 200 moves upward. When the first groove 410 on the opening sleeve 200 moves to the first C-type locking ring 420 on the closing sleeve 300, the first C-type locking ring 420 returns to its original state and is inserted into the first groove 410, the opening sleeve 200 and the closing sleeve 300 are in the first locking state. At this time, the sandblasting hole 001 is open and the sleeve is in the open state.

[0034] Preferably, a sealing ring 1400 is provided on the opening sliding sleeve 200 and the closing sliding sleeve 300 respectively, so that the closing sliding sleeve 300 can be effectively sealed.

[0035] In an optional scheme of this embodiment, the opening sleeve 200 is fixed to the body 100 by the first shear nail 1200, and the closing sleeve 300 is fixed to the body 100 by the second shear nail 1300; in the first working state, after the packer completes the sealing, the pressure in the tubing string is accumulated, and the pressure acts on the opening sleeve 200. Through the area difference on the opening sleeve 200, the opening sleeve 200 is pushed to cut off the first shear nail 1200, and the opening sleeve 200 is unlocked from the body 100 and moves upward; in the second working state, by applying a downward force to the closing sleeve 300, the second shear nail 1300 is broken, and the closing sleeve 300 is unlocked from the body 100, and after the first working state, the opening sleeve 200 and the closing sleeve 300 are locked, and the closing sleeve 300 pushes the opening sleeve 200 to move downward together.

[0036] In an optional solution of this embodiment, the closable differential pressure sleeve further includes an upper joint 700 disposed on the upper part of the body 100, the upper joint 700 and the body 100 are connected via a connecting sleeve 800, the upper part of the connecting sleeve 800 is located inside the upper joint 700, and the lower part of the connecting sleeve 800 is located inside the body 100. The upper joint 700 is connected to the pipe string via threads.

[0037] In an optional solution of this embodiment, the closable differential pressure sleeve further includes a lower joint 1500 disposed at the lower part of the body 100, and the lower joint 1500 and the body 100 are connected by bolts. The lower joint 1500 is provided with an external thread, the pipe column is provided with an internal thread, and the lower joint 1500 and the pipe column are threaded.

[0038] In an optional scheme of this embodiment, the closed pressure differential sleeve drives the closing sleeve 300 to move downward through a closing ball plug 600. If the sleeve 300 needs to be closed, the closing ball plug 600 matching the sleeve is inserted. When the closing ball plug 600 falls onto the closing sleeve 300, the second shear pin 1300 is pressed, thereby releasing the lock between the closing sleeve 300 and the main body 100.

[0039] For the shape and structure of the closing ball plug 600, please refer to Figure 3 and Figure 4The closing ball plug 600 includes a cylindrical upper ball plug 610 and a lower ball plug 620 with a smooth arc surface. The outer diameter of the upper ball plug 610 matches the inner diameter of the upper joint 700, and the lower ball plug 620 is inserted into the top opening of the closing sleeve 300. Preferably, a sealing ring 1400 is provided on the closing ball plug 600. When the sleeve is closed, if the sealing ring 1400 on the closing sleeve 300 fails to form a seal, the sealing ring 1400 on the closing ball plug 600 and the closing sleeve 300 can form a self-sealing, forming a "double insurance" for closing the sleeve.

[0040] In an optional scheme of this embodiment, the top wall of the connecting sleeve 800 and the lower part of the upper joint 700 form a first annular groove with an opening facing the interior of the upper joint 700; a step structure is provided on the outer side of the upper part of the closing sleeve 300. In the first working state, the lower end face of the connecting sleeve 800 abuts against the upper end face of the step structure of the closing sleeve 300 and the upper part of the outer wall of the closing sleeve 300 fits against the inner wall of the upper joint 700, thereby compressing the second C-type locking ring 520 into the first annular groove.

[0041] The second locking mechanism 500 includes a second groove 510 located on the closing ball plug 600 and a second C-type locking ring 520 located in the first annular groove; when the closing ball plug 600 is put into operation, the closing ball plug 600 breaks the second shear pin 1300 when it falls onto the closing sleeve 300, and the closing sleeve 300 is unlocked from the main body 100, and the closing ball plug 600 pushes the closing sleeve 300 to move downward, and when the second groove 510 on the closing ball plug 600 moves to the second C-type locking ring 520, the second C-type locking ring 520 returns to its original state and is inserted into the second groove 510, thereby opening the sleeve 200, the closing sleeve 300 and the closing ball plug 600 are in the second locking state, and at this time, the sandblasting hole 001 is closed.

[0042] In an optional scheme of this embodiment, a liquid outlet 002 is provided on the upper part of the upper joint 700, and an outer sleeve 900 is provided on the outer part of the upper joint 700 and the main body 100; in a first working state, the outer sleeve 900 is in a locked state with the main body 100 through a third locking mechanism 1000, and the outer sleeve 900 blocks the liquid outlet 002; in a second working state, the outer sleeve 900 is unlocked from the main body 100.

[0043] In the optional solution of this embodiment, the third locking mechanism 1000 includes a fixed locking block 1010, and the fixed locking block 1010 has a locking state and an unlocking state. The body 100 is provided with a first opening, and the outer sleeve 900 is provided with a third groove. In the first working state, when the fixed locking block 1010 is in the locking state, the closing sleeve 300 presses the fixed locking block 1010 outward so that the fixed locking block 1010 passes through the first opening and the third groove at the same time, thereby locking the outer sleeve 900 and the body 100, and the liquid outlet 002 is blocked by the outer sleeve 900; in the second working state, when the closing sleeve 300 moves downward, the step structure of the closing sleeve 300 moves to the fixed locking block 1010, and the fixed locking block 1010 loses the squeezing force and slides inward and enters the gap formed by the step structure and the body 100, and the fixed locking block 1010 is separated from the outer sleeve 900, thereby releasing the locking of the outer sleeve 900 and the body 100.

[0044] In the optional scheme of this embodiment, the outer periphery of the upper joint 700 is provided with a first step 710, and the outer periphery of the body 100 is provided with a second step 110, and the first step 710 and the second step 110 form an installation space; the top of the outer sleeve 900 abuts against the first step 710, and a telescopic member is provided between the bottom of the outer sleeve 900 and the end face of the second step 110, and the telescopic member is configured to always have a tendency to drive the outer sleeve 900 to move upward in the installation space. When liquid flows in the pipe column, the outer sleeve 900 moves downward under the pressure of the liquid and opens the liquid outlet 002, and the liquid in the pipe column flows out; when the liquid pressure decreases, the telescopic member pushes the outer sleeve 900 to move upward and blocks the liquid outlet 002.

[0045] Preferably, the telescopic member can be set as a compression spring 1100, the upper end of the compression spring 1100 is connected to the bottom of the outer sleeve 900, and the lower end of the compression spring 1100 is connected to the upper end surface of the second step 110. The compression spring 1100 is always in a compressed state and has a tendency to drive the outer sleeve 900 to move upward. The outer sleeve 900 and the compression spring 1100 form a one-way valve system to ensure that the entire pipe column forms a liquid flow channel through the liquid outlet 002 to meet various upper construction requirements.

[0046] The working process of the closable differential pressure sleeve is described as follows:

[0047] The closable differential pressure sleeve is lowered together with the fracturing operation string. At this time, the closable differential pressure sleeve is in the initial state. Figure 1As shown, after the tubing string is lowered to the designed position, a sealing ball is inserted, and when the sealing ball reaches the sealing ball seat position, the sealing packer is pressed. After the packer completes the sealing, the pressure in the tubing string is accumulated, and the pressure acts on the opening sleeve 200. Through the area difference on the opening sleeve 200, the opening sleeve 200 is pushed to cut off the first shear nail 1200, and the locking of the opening sleeve 200 and the body 100 is released. The opening sleeve 200 moves upward under the action of pressure, and when the first groove 410 on the opening sleeve 200 reaches the first C-type locking ring 420, the first C-type locking ring 420 returns to its original state, realizing the locking of the opening sleeve 200 and the closing sleeve 300. At this time, the sleeve is fully opened to make way for the sandblasting hole 001, as shown in FIG. Figure 2 As shown, fracturing construction can be carried out.

[0048] If you need to close the sliding sleeve 300, Figure 3 As shown, a closing ball plug 600 matching the sliding sleeve is put in, and when the closing ball plug 600 falls on the closing sliding sleeve 300, it presses and cuts the second shear pin 1300, and at this time, the closing ball plug 600 pushes the closing sliding sleeve 300 and the opening sliding sleeve 200 to move downward together, and when the second groove 510 on the closing ball plug 600 moves to the second C-shaped locking ring 520, the second C-shaped locking ring 520 returns to its original state to achieve locking so that the closing sliding sleeve 300, the opening sliding sleeve 200 and the closing ball plug 600 form a locked state, and at this time, Figure 4 As shown, the sandblasting hole 001 is closed. During the closing process of the sleeve, when the sealing rings 1400 on the closing sleeve 300 and the opening sleeve 200 fail to form a seal, the sealing ring 1400 on the closing ball plug 600 and the upper joint 700 can form a self-sealing, forming a "double insurance" for the closing of the sleeve; at the same time, during the downward movement of the closing sleeve 300, the fixed locking block 1010 loses its extrusion, and the fixed locking block 1010 moves inward and disengages from the third groove to unlock the outer sleeve 900 and the body 100. After the sleeve is closed, the outer sleeve 900 and the compression spring 1100 form a one-way valve system to ensure that the entire pipe string forms a liquid flow channel through the liquid outlet hole 002 to meet various upper construction needs, such as Figure 5 shown.

[0049] The closable differential pressure sleeve provided in the present invention can achieve the following beneficial effects:

[0050] 1. The sliding sleeve can be closed after opening;

[0051] 2. The opening and closing process of the sliding sleeve is realized by the movement of two sliding sleeves respectively. The two processes do not interfere with each other and the operation is reliable;

[0052] 3. The opening and closing of the sliding sleeve are locked by the locking ring to ensure the stability of the opening and closing state;

[0053] 4. The pressure differential sleeve can be closed by throwing the closing ball plug 600, which is simple and convenient to operate;

[0054] 5. The closing ball plug 600 and the upper joint 700 can be self-sealed, realizing the "double insurance" of the closing of the sliding sleeve;

[0055] 6. After the sleeve is closed, the liquid outlet hole 002 can be opened to provide a liquid passage for other operations in the reservoir above the pressure differential sleeve.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A closable differential pressure sleeve, characterized in that: It comprises a body (100) with a sandblasting hole (001) at the bottom, an opening sleeve (200) arranged in the body (100), and a closing sleeve (300) arranged above the opening sleeve (200), wherein the opening sleeve (200) blocks the sandblasting hole (001); In a first working state, the opening sliding sleeve (200) moves upward, and the opening sliding sleeve (200) and the closing sliding sleeve (300) are locked in a first locking state through a first locking mechanism (400), and at this time, the sandblasting hole (001) is opened; In the second working state, the closing sliding sleeve (300) pushes the opening sliding sleeve (200) to move downward, and the opening sliding sleeve (200) and the closing sliding sleeve (300) are locked in a second locking state through a second locking mechanism (500), and at this time, the sandblasting hole (001) is closed; It also includes an upper joint (700) disposed on the upper part of the body (100), the upper joint (700) and the body (100) being connected via a connecting sleeve (800), the upper part of the connecting sleeve (800) being located inside the upper joint (700), and the lower part of the connecting sleeve (800) being located inside the body (100); The closed differential pressure sliding sleeve drives the closing sliding sleeve (300) to move downwards via a closing ball plug (600); The closing ball plug (600) comprises a cylindrical upper ball plug (610) and a lower ball plug (620) provided with a smooth arc surface, the outer diameter of the upper ball plug (610) matches the inner diameter of the upper joint (700), and the lower ball plug (620) is inserted into the top opening of the closing sliding sleeve (300); The top wall of the connecting sleeve (800) and the lower part of the upper joint (700) form a first annular groove with an opening facing the interior of the upper joint (700); The second locking mechanism (500) comprises a second groove (510) located on the closing ball plug (600) and a second C-shaped locking ring (520) located in the first annular groove, and when the second C-shaped locking ring (520) is restored to its original state and inserted into the second groove (510), the opening sliding sleeve (200), the closing sliding sleeve (300) and the closing ball plug (600) are in the second locking state; The upper portion of the upper joint (700) is provided with a liquid outlet hole (002), and the upper joint (700) and the outer portion of the body (100) are sheathed with an outer sleeve (900); In the first working state, the outer sleeve (900) is in a locked state with the body (100) via a third locking mechanism (1000), and the outer sleeve (900) blocks the liquid outlet hole (002); In the second working state, the outer sleeve (900) and the body (100) are unlocked; The third locking mechanism (1000) comprises a fixed locking block (1010), the fixed locking block (1010) has a locked state and an unlocked state, the body (100) is provided with a first opening, and the outer sleeve (900) is provided with a third groove; When the fixed locking block (1010) is in a locked state, the closing sliding sleeve (300) presses the fixed locking block (1010) outwardly so that the fixed locking block (1010) passes through the first opening and the third groove at the same time, thereby locking the outer sleeve (900) and the body (100); When the fixed locking block (1010) is in an unlocked state, the fixed locking block (1010) loses the squeezing force of the closing sliding sleeve (300); The outer periphery of the upper joint (700) is provided with a first step (710), the outer periphery of the body (100) is provided with a second step (110), and the first step (710) and the second step (110) form an installation space; The top of the outer sleeve (900) abuts against the first step (710), and a telescopic member is provided between the bottom of the outer sleeve (900) and the end surface of the second step (110), and the telescopic member is configured to always have a tendency to drive the outer sleeve (900) to move upward in the installation space; The telescopic member may be configured as a compression spring (1100), the upper end of the compression spring (1100) being connected to the bottom of the outer sleeve (900), and the lower end of the compression spring (1100) being connected to the upper end surface of the second step (110); The compression spring (1100) is always in a compressed state and has a tendency to drive the outer sleeve (900) to move upward.

2. The closable differential pressure sleeve according to claim 1, characterized in that: A first sliding section (210) is provided on the upper portion of the opening sliding sleeve (200), and a gap is provided between the first sliding section (210) and the body (100); A second sliding section (310) is provided at the lower part of the closing sliding sleeve (300), and the second sliding section (310) extends into a gap formed by the first sliding section (210) and the body (100); The first sliding section (210) and the second sliding section (310) are slidably connected.

3. The closable differential pressure sleeve according to claim 2, characterized in that: The first locking mechanism (400) comprises a first groove (410) located on the outer end surface of the first sliding section (210) and a first C-shaped locking ring (420) located on the inner end surface of the second sliding section (310); when the first C-shaped locking ring (420) is restored to its original state and inserted into the first groove (410), the opening sliding sleeve (200) and the closing sliding sleeve (300) are in the first locking state.

4. The closable differential pressure sleeve according to claim 1, characterized in that: The opening sliding sleeve (200) is fixed to the body (100) via a first shear pin (1200), and the closing sliding sleeve (300) is fixed to the body (100) via a second shear pin (1300); In the first working state, the first shear pin (1200) is sheared off, and the opening sliding sleeve (200) moves upward; In the second working state, the second shear pin (1300) is sheared off, and the closing sliding sleeve (300) pushes the opening sliding sleeve (200) to move downward.

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