A hydraulic self-locking circulation valve for oilfield exploitation

Abstract

The present invention discloses a hydraulic self-locking circulation valve for oilfield exploitation, belonging to the technical field of circulation valves. It includes a positioning sleeve arranged in an oil well. The positioning sleeve is provided with a communication hole, and a connecting sleeve is installed on the positioning sleeve. An inner sliding sleeve is slidably connected in the positioning sleeve, and a trigger sliding sleeve is slidably connected to the inner sliding sleeve. The trigger sliding sleeve is slidably connected with a first sliding ring and a second sliding ring. A plurality of elastic support bars evenly distributed circumferentially are fixedly connected between the first sliding ring and the adjacent second sliding ring. In the present invention, the trigger sliding sleeve is supported by the elastic support bars, so that the axis of the trigger sliding sleeve is close to the axis of the inner sliding sleeve, reducing the probability that the trigger sliding sleeve deviates during the sliding process under the influence of its own gravity, thereby reducing the probability that the trigger sliding sleeve is stuck by the wrong inner sliding sleeve, ensuring that the trigger sliding sleeve can move smoothly to the correct inner sliding sleeve, and further ensuring the normal use of the device.

Description

Technical Field

[0001] The present invention relates to the technical field of circulation valves, and in particular to a hydraulic self-locking circulation valve for oilfield exploitation. Background Art

[0002] The circulation valve for oilfield exploitation is one of the key components in the layer-by-layer filling sand control tool. The existing circulation valve consists of an external pipeline, an internally slidable inner sliding sleeve, and a trigger sliding sleeve for driving the inner sliding sleeve to move, etc. The circulation valve is generally provided with a hydraulic self-locking structure. The hydraulic self-locking structure utilizes the hydraulic pressure generated by the flow of fracturing fluid to push the matching structure of the trigger sliding sleeve and the inner sliding sleeve to achieve tight sealing and form a stable hydraulic locking state.

[0003] During the use of the existing circulation valve, several trigger sliding sleeves with different outer diameters need to be respectively placed into the corresponding inner sliding sleeves. This requires the trigger sliding sleeve to pass through multiple inner sliding sleeves during the placement process, and it is required that the trigger sliding sleeve can be hermetically fitted with the corresponding inner sliding sleeve. However, when the trigger sliding sleeve travels in a horizontal oil well, affected by gravity, the trigger sliding sleeve will deflect downward, resulting in the trigger sliding sleeve being easily stuck at the wrong inner sliding sleeve, causing the trigger sliding sleeve to be unable to move smoothly to the correct inner sliding sleeve, thereby affecting the normal use of the circulation valve. Summary of the Invention

[0004] In order to overcome the shortcomings pointed out in the above background art, the present invention provides a hydraulic self-locking circulation valve for oilfield exploitation.

[0005] The technical solution of the present invention is: A hydraulic self-locking circulation valve for oilfield exploitation, including a plurality of positioning sleeves arranged in a straight line and all disposed in the oil well. The positioning sleeve is provided with a communication hole. Connecting sleeves are installed on both sides of the positioning sleeve. An inner sliding sleeve is slidably connected in the positioning sleeve. The inner sliding sleeve is used to block the adjacent communication holes. A first elastic member is fixedly connected between the inner sliding sleeve and the adjacent positioning sleeve. A trigger sliding sleeve is slidably connected to the inner sliding sleeve. The trigger sliding sleeve is provided with a recovery channel. All the positioning sleeves and all the connecting sleeves are jointly provided with a recovery rod for recovering all the trigger sliding sleeves. The trigger sliding sleeve is slidably connected with a first sliding ring and a second sliding ring. A limiting portion for blocking the adjacent second sliding ring is arranged in the inner sliding sleeve. A plurality of elastic support bars evenly distributed in the circumferential direction are fixedly connected between the first sliding ring and the adjacent second sliding ring. When the elastic support bars are located in the adjacent inner sliding sleeve, the elastic support bars are straightened by the adjacent inner sliding sleeve. After the elastic support bars are separated from the adjacent inner sliding sleeve, the middle parts of the elastic support bars evenly distributed in the circumferential direction respectively open to the surroundings.

[0006] Preferably, a soluble ball is installed in the recovery channel. From the wellhead to the bottom of the oil well, the inner diameters of all the inner sliding sleeves, the outer diameters of all the trigger sliding sleeves, the inner diameters of all the limiting parts, the outer diameters of all the first sliding rings, and the outer diameters of all the second sliding rings decrease in sequence.

[0007] Preferably, a sealing ring is fixedly connected to the second sliding ring, and the sealing ring is in contact with the adjacent limiting part.

[0008] Preferably, a rotating ball is rotatably connected in the trigger sliding sleeve. The rotating ball is provided with a first channel, and the rotating ball is used to block the recovery channel, and the first channel is used to communicate with the recovery channel.

[0009] Preferably, a second channel is arranged in the trigger sliding sleeve. A pressing rod is hermetically slidably connected in the second channel. A second elastic member is fixedly connected between the trigger sliding sleeve and the adjacent pressing rod, and the pressing rod is used to press the adjacent first sliding ring.

[0010] Preferably, the trigger sliding sleeve is provided with a plurality of stepped parts distributed linearly, and the stepped parts are used to limit the elastic support strips.

[0011] Preferably, the inner diameter of the stepped part is larger than the inner diameter of the corresponding limiting part, the inner diameter of the stepped part is smaller than the outer diameter of the corresponding first sliding ring, the inner diameter of the stepped part is larger than the outer diameter of the corresponding second sliding ring, and the stepped part on the trigger sliding sleeve far from the limiting part is used to block the corresponding first sliding ring.

[0012] Preferably, a torsion spring is fixedly connected between the rotating ball and the adjacent trigger sliding sleeve.

[0013] Preferably, the trigger sliding sleeve is provided with a third channel. A blocking ring for blocking the third channel is slidably connected in the trigger sliding sleeve. A plurality of elastic telescopic plates distributed circumferentially are slidably connected to the recovery rod. The blocking ring is provided with a groove, and the groove of the blocking ring is used for the elastic telescopic plate of the recovery rod to enter. The rotating ball is provided with a pressure-receiving part, and the pressure-receiving part is located in the third channel. A blocking part for blocking the adjacent pressure-receiving part is arranged in the third channel.

[0014] Preferably, the contact surfaces between the blocking ring and the adjacent trigger sliding sleeve are all friction surfaces. The frictional resistance when the blocking ring slides is A, and the acting force required for the elastic telescopic plate on the recovery rod to be compressed is B, and A < B.

[0015] The present invention has the following advantages: 1. The present invention supports the trigger sliding sleeve through an elastic support strip, so that the axis of the trigger sliding sleeve is close to the axis of the inner sliding sleeve, reducing the probability of the trigger sliding sleeve being deflected under the influence of its own gravity during the sliding process, thereby reducing the probability of the trigger sliding sleeve being stuck by the wrong inner sliding sleeve, ensuring that the trigger sliding sleeve can smoothly move to the correct inner sliding sleeve, and further ensuring the normal use of the device;

[0016] 2. By setting the rotating ball, it is possible to recycle all trigger sliding sleeves without using soluble balls and without having to calculate the exact dissolution time of the soluble balls and the time required for fracturing in advance. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0018] Figure 2 is a three-dimensional structural schematic diagram of the inner sliding sleeve of the present invention;

[0019] Figure 3 is a three-dimensional structural schematic diagram of the trigger sliding sleeve of the present invention;

[0020] Figure 4 is a three-dimensional structural schematic diagram of the first sliding ring and the second sliding ring of the present invention;

[0021] Figure 5 is a three-dimensional structural schematic diagram of the elastic support strip of the present invention;

[0022] Figure 6 is a sectional view of the three-dimensional structure of the first sliding ring and the second sliding ring of the present invention;

[0023] Figure 7 is a three-dimensional structural schematic diagram of the rotating ball of the present invention;

[0024] Figure 8 is a three-dimensional structural schematic diagram of the pressure-receiving part and the blocking part of the present invention.

[0025] Wherein: 1 - positioning sleeve, 2 - communication hole, 3 - connecting sleeve, 4 - inner sliding sleeve, 5 - trigger sliding sleeve, 501 - recovery channel, 502 - recovery rod, 503 - limiting part, 6 - first sliding ring, 7 - second sliding ring, 8 - elastic support strip, 9 - sealing ring, 11 - rotating ball, 1101 - first channel, 12 - second channel, 13 - extrusion rod, 14 - step part, 15 - third channel, 16 - plugging ring, 17 - pressure-receiving part, 18 - blocking part. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but it is not limited to the present invention. Embodiment 1

[0027] This embodiment discloses a hydraulic self-locking circulation valve for oilfield exploitation, which is used to stabilize the pressure during fracturing construction.

[0028] As Figures 1-6 shown, it includes a plurality of positioning sleeves 1 arranged in a straight line and all disposed in the oil well. There is a gap between this device and the oil well. The positioning sleeve 1 is provided with two communication holes 2 symmetrically distributed up and down. Connecting sleeves 3 are installed on both the left and right sides of the positioning sleeve 1. The positioning sleeve 1 is communicated with the oil well pipeline through the connecting sleeves 3 on both sides. The oil well pipeline is an existing structure and is not shown in the figure. Only two positioning sleeves 1 and four connecting sleeves 3 are shown in the figure. During the use of this device, a plurality of positioning sleeves 1 need to be connected together through the oil well pipeline and the connecting sleeves 3. An inner sliding sleeve 4 is slidably connected to the positioning sleeve 1. The inner diameter of the left side of the inner sliding sleeve 4 is not less than the inner diameter of the connecting sleeve 3 on its left side to reduce the extrusion force generated by the liquid on the left side of the inner sliding sleeve 4. The inner sliding sleeve 4 is used to block two adjacent communication holes 2. A first elastic member is fixedly connected between the inner sliding sleeve 4 and the adjacent positioning sleeve 1. Among them, the first elastic member between the inner sliding sleeve 4 and the adjacent positioning sleeve 1 is a compression spring. A trigger sliding sleeve 5 is slidably connected to the inner sliding sleeve 4. The trigger sliding sleeve 5 is detachably divided into upper and lower parts for facilitating the production and manufacturing of the structure inside the trigger sliding sleeve 5. The trigger sliding sleeve 5 is provided with a recovery channel 501. A soluble ball is installed in the recovery channel 501. In this embodiment, the recovery channel 501 is blocked by the soluble ball. The material of the soluble ball can be magnesium alloy or aluminum alloy. In the fracturing fluid, the soluble ball will react with the fracturing fluid and gradually dissolve. The soluble ball is used to block the recovery channel 501. All the positioning sleeves 1 and all the connecting sleeves 3 are jointly provided with a recovery rod 502. The recovery rod 502 is an existing structure and is used to recover all the trigger sliding sleeves 5. The trigger sliding sleeve 5 is slidably connected to a first sliding ring 6 and a second sliding ring 7. A limiting portion 503 for blocking the adjacent second sliding ring 7 is provided inside the inner sliding sleeve 4. After the limiting portion 503 blocks the adjacent second sliding ring 7, the maximum outer diameter of the trigger sliding sleeve 5 fits with the corresponding inner sliding sleeve 4 to block the inner sliding sleeve 4. A plurality of circumferentially uniformly distributed elastic support strips 8 are fixedly connected between the first sliding ring 6 and the adjacent second sliding ring 7. The sliding range of the first sliding ring 6 is greater than the sliding range of the second sliding ring 7. The elastic support strips 8 shown in the figure are in a compressed state. When the elastic support strips 8 are located inside the adjacent inner sliding sleeve 4, the elastic support strips 8 are straightened by the adjacent inner sliding sleeve 4. After the elastic support strips 8 are separated from the adjacent inner sliding sleeve 4, the middle parts of the circumferentially uniformly distributed elastic support strips 8 open to the surroundings respectively, causing the first sliding ring 6 to move to the right.

[0029] From the wellhead to the bottom of the oil well, the inner diameters of all the inner sliding sleeves 4, the outer diameters of all the trigger sliding sleeves 5, the inner diameters of all the limiting parts 503, the outer diameters of all the first sliding rings 6, and the outer diameters of all the second sliding rings 7 decrease successively. During use, first place the trigger sliding sleeve 5 with the smallest outer diameter. Insert the trigger sliding sleeve 5 from the left side into the rightmost inner sliding sleeve 4, and then place another trigger sliding sleeve 5 with a slightly larger outer diameter. Repeat this step and insert the trigger sliding sleeves 5 with different outer diameters into the inner sliding sleeves 4 with different inner diameters in sequence.

[0030] As Figure 5 shown in Figure 6 Figure, a sealing ring 9 is fixedly connected to the second sliding ring 7. The sealing ring 9 is made of a flexible material and fits with the adjacent limiting part 503 for sealing between the second sliding ring 7 and the limiting part 503. When an elastic support strip 8 deforms, the elastic support strip 8 drives the first sliding ring 6 to slide, causing all the elastic support strips 8 to deform. The force required for the elastic support strip 8 to deform is greater than the sum of the gravity of the trigger sliding sleeve 5, the gravity of the first sliding ring 6, and the gravity of the second sliding ring 7. All the elastic support strips 8 on the trigger sliding sleeve 5 need to deform synchronously to cause the axis of the trigger sliding sleeve 5 to be misaligned, so as to enhance the stability of the position of the trigger sliding sleeve 5.

[0031] In this embodiment, the working process of the hydraulic self-locking circulation valve for oilfield exploitation is as follows:

[0032] When the device needs to be used, the operator first needs to introduce the trigger sliding sleeve 5 with the smallest outer diameter into the rightmost inner sliding sleeve 4. The operator injects liquid (in this case, fracturing fluid) into the oil well pipeline, so that the fracturing fluid flows through all the positioning sleeves 1 from left to right in sequence. The fracturing fluid carries the trigger sliding sleeve 5 to move to the right. When the trigger sliding sleeve 5 moves from left to right, the circumferentially uniformly distributed elastic support strips 8 support the trigger sliding sleeve 5 to keep the axis of the trigger sliding sleeve 5 close to the axis of the inner sliding sleeve 4, reducing the probability that the trigger sliding sleeve 5 deflects downward under the influence of its own gravity during the rightward sliding process, thereby reducing the probability that the trigger sliding sleeve 5 is stuck by the left inner sliding sleeve 4, so as to ensure that the trigger sliding sleeve 5 can move smoothly to the rightmost inner sliding sleeve 4, and further ensure the normal use of this device.

[0033] When the trigger sliding sleeve 5 moves to the corresponding inner sliding sleeve 4, along with the rightward movement of the trigger sliding sleeve 5, the trigger sliding sleeve 5 drives the first sliding ring 6 and the second sliding ring 7 to move to the right. The trigger sliding sleeve 5 is inserted into the corresponding inner sliding sleeve 4. During the rightward movement of the first sliding ring 6 and the second sliding ring 7, the first sliding ring 6 and the second sliding ring 7 jointly drive the elastic support strip 8 to move to the right. During the process that the elastic support strip 8 is inserted into the inner sliding sleeve 4, the elastic support strip 8 is flattened by the inner sliding sleeve 4, and then the limiting part 503 blocks the second sliding ring 7, and the trigger sliding sleeve 5 blocks the inner sliding sleeve 4.

[0034] After the trigger sleeve 5 blocks the inner sleeve 4, as the trigger sleeve 5 moves to the right, the trigger sleeve 5 squeezes the inner sleeve 4 to move to the right through the limiting portion 503. The first elastic member between the inner sleeve 4 and the adjacent positioning sleeve 1 is compressed. The inner sleeve 4 moves to the right and loses the blockage of the two communication holes 2. The fracturing fluid is discharged through the two communication holes 2 into the oil well to fracture the first section on the right side of the oil well.

[0035] After the first section on the right side of the oil well is fractured, the operator places the next trigger sleeve 5 into the oil well pipeline and repeats the above operation, so that the next trigger sleeve 5 moves into the second inner sleeve 4 from the right. The second inner sleeve 4 from the right is blocked, and the fracturing fluid no longer discharges through the two communication holes 2 at the rightmost inner sleeve 4. Then the second inner sleeve 4 from the right moves to the right due to being squeezed by the corresponding trigger sleeve 5, and the two communication holes 2 at the second inner sleeve 4 from the right are opened to fracture the second section on the right side of the oil well. Repeat the above operation in this way, and place the trigger sleeves 5 with different outer diameters into the corresponding inner sleeves 4 respectively to quickly achieve staged fracturing of the oil well.

[0036] After the oil well fracturing is completed, the fracturing fluid gradually dissolves the soluble balls in the trigger sleeve 5. When the soluble balls are dissolved, the recovery channels 501 are unblocked. The operator inserts the recovery rod 502 into all the recovery channels 501 and makes the recovery rod 502 snap into the rightmost recovery channel 501. The recovery rod 502 drives the rightmost trigger sleeve 5 to move to the left, and the rightmost trigger sleeve 5 moves to the left and drives the adjacent trigger sleeve 5 to move to the left. In this way, all the trigger sleeves 5 are moved to the left in turn to recover all the trigger sleeves 5.

[0037] During the process of recovering the trigger sleeve 5, the first elastic member rebounds and resets, causing the inner sleeve 4 to slide back to its original position, and the communication hole 2 is blocked again by the adjacent inner sleeve 4. If it is necessary to circulate the fracturing fluid out of the oil well, the rightmost trigger sleeve 5 is not removed, so that the rightmost communication hole 2 is not blocked. The operator injects the isolation fluid into the oil well pipeline, and the isolation fluid is discharged through the rightmost communication hole 2 into the gap between this device and the oil well. The isolation fluid squeezes the fracturing fluid in this gap out of the oil well. Finally, the proppant is filled into the oil well pipeline, so that the proppant enters the fractured gap through the rightmost communication hole 2 to support the fractured structure. Embodiment 2

[0038] This embodiment discloses a hydraulic self-locking circulation valve for oilfield exploitation, which is further improved on the basis of Embodiment 1.

[0039] Such as Figure 5 And Figure 7As shown, in the above embodiment, the recovery channel 501 is blocked by a soluble ball. In this embodiment, the rotary ball 11 replaces the soluble ball to block the recovery channel 501. The rotary ball 11 is rotatably connected inside the trigger sleeve 5. The rotary ball 11 is provided with a first channel 1101. The rotary ball 11 is used to block the recovery channel 501, and the first channel 1101 is used to communicate with the recovery channel 501. The aperture of the first channel 1101 is the same as the inner diameter of the trigger sleeve 5. When the rotary ball 11 rotates 90°, the axis of the first channel 1101 is collinear with the axis of the recovery channel 501.

[0040] As Figure 5 shown Figure 7 As shown, a second channel 12 is provided inside the trigger sleeve 5. A push rod 13 is hermetically and slidably connected inside the second channel 12. The left part of the push rod 13 is hermetically and slidably connected with the second channel 12, and the right part of the push rod 13 is non-hermetically connected with the second channel 12. A second elastic member is fixedly connected between the trigger sleeve 5 and the adjacent push rod 13. The material of the second elastic member is silicon manganese spring steel to adapt to the temperature in the fracturing environment. The second elastic member between the trigger sleeve 5 and the adjacent push rod 13 is a compression spring. When the liquid passes through the recovery channel 501, if the recovery channel 501 is blocked by the adjacent rotary ball 11, a part of the liquid passes through the adjacent second channel 12 to squeeze the adjacent push rod 13, so that the push rod 13 moves to the right to squeeze the adjacent first sliding ring 6, and the second elastic member between the trigger sleeve 5 and the adjacent push rod 13 is compressed. The push rod 13 is used to squeeze the adjacent first sliding ring 6.

[0041] As Figure 4 shown, the trigger sleeve 5 is provided with a plurality of stepped portions 14 distributed linearly. The stepped portions 14 are used to limit the elastic support strip 8. The elastic support strip 8 is made of engineering plastic, such as polyphenylene sulfide. When the push rod 13 moves to the right to squeeze the adjacent first sliding ring 6, the first sliding ring 6 moves to the right, causing the elastic support strip 8 to deform and embed between the plurality of stepped portions 14.

[0042] The inner diameter of the stepped portion 14 is larger than the inner diameter of the corresponding limiting portion 503, the inner diameter of the stepped portion 14 is smaller than the outer diameter of the corresponding first sliding ring 6, and the inner diameter of the stepped portion 14 is larger than the outer diameter of the corresponding second sliding ring 7. When the sealing ring 9 is not deformed and the elastic support strip 8 is straightened, there is a distance between the first sliding ring 6 and the adjacent stepped portion 14. After the push rod 13 moves to the right to squeeze the adjacent first sliding ring 6, the first sliding ring 6 abuts against the stepped portion 14 on the left side of the corresponding inner sleeve 4. The stepped portion 14 on the left side of the trigger sleeve 5 blocks the corresponding first sliding ring 6. The elastic support strip 8 deforms and squeezes the adjacent second sliding ring 7 to move to the right, and the second sliding ring 7 squeezes the adjacent sealing ring 9, causing the sealing ring 9 to deform.

[0043] As Figure 7 shownFigure 8 As shown in Figure 8 , the trigger sliding sleeve 5 is provided with a third channel 15. A plugging ring 16 for plugging the third channel 15 is slidably connected inside the trigger sliding sleeve 5. The recovery rod 502 is slidably connected with a plurality of circumferentially distributed elastic telescopic plates. The right part of the elastic telescopic plates on the recovery rod 502 is provided with an inclined surface. The contact surfaces between the plugging ring 16 and the adjacent trigger sliding sleeves 5 are all friction surfaces. The frictional resistance when the plugging ring 16 slides is A, and the acting force required for the elastic telescopic plates on the recovery rod 502 to be compressed is B, and A < B. When the inclined surface is squeezed by the trigger sliding sleeve 5, the elastic telescopic plates on the recovery rod 502 move and contract. Along with the movement of the recovery rod 502, after the inclined surface of the elastic telescopic plates on the recovery rod 502 moves out of contact with the trigger sliding sleeve 5, the elastic telescopic plates on the recovery rod 502 rebound and reset. The plugging ring 16 is provided with a groove for the elastic telescopic plates of the recovery rod 502 to enter. The rotating ball 11 is provided with a pressure-receiving part 17, and the pressure-receiving part 17 is located in the third channel 15. A blocking part 18 for blocking the adjacent pressure-receiving parts 17 is arranged in the third channel 15. After the pressure-receiving part 17 is impacted by the liquid flow, the pressure-receiving part 17 rotates 90° and contacts the blocking part 18, and the pressure-receiving part 17 no longer rotates. A torsion spring is fixedly connected between the rotating ball 11 and the adjacent trigger sliding sleeve 5. When the liquid stops flowing, the liquid pressure received by the pressure-receiving part 17 decreases, and the torsion spring between the rotating ball 11 and the adjacent trigger sliding sleeve 5 resets, causing the rotating ball 11 to rotate and reset. The maximum outer diameter of the recovery rod 502 is smaller than the inner diameters of all the recovery channels 501.

[0044] The working process of this embodiment is as follows:

[0045] During the process of placing the trigger sliding sleeve 5 into the corresponding inner sliding sleeve 4, the rotating ball 11 plugs the inner sliding sleeve 4. The liquid squeezes the extrusion rod 13 through the second channel 12. The extrusion rod 13 moves to the right, and the second elastic member between the trigger sliding sleeve 5 and the adjacent extrusion rod 13 is compressed. The extrusion rod 13 moves to the right and squeezes the adjacent first sliding ring 6. The first sliding ring 6 squeezes all the adjacent elastic support strips 8, causing the elastic support strips 8 to deform and be embedded between several stepped parts 14. The elastic support strips 8 deform and squeeze the adjacent second sliding ring 7 to move to the right. The second sliding ring 7 squeezes the adjacent sealing ring 9, causing the sealing ring 9 to deform and enhancing the sealing performance between the trigger sliding sleeve 5 and the inner sliding sleeve 4.

[0046] ​When it is necessary to recover the trigger sleeve 5, the operator repeats the steps of the above embodiment, inserts the recovery rod 502 into the recovery channel 501. The inclined surface of the elastic telescopic plate on the recovery rod 502 is squeezed by the trigger sleeve 5, and the elastic telescopic plate on the recovery rod 502 moves and contracts. When the elastic telescopic plate on the recovery rod 502 moves into the groove of the sealing ring 16 and the inclined surface of the elastic telescopic plate on the recovery rod 502 loses pressure, the elastic telescopic plate on the recovery rod 502 rebounds and resets. Along with the rightward movement of the elastic telescopic plate on the recovery rod 502, the elastic telescopic plate of the recovery rod 502 drives the sealing ring 16 to move rightward, so that the sealing ring 16 no longer blocks the third channel 15. The liquid squeezes the pressure-receiving part 17 through the third channel 15, and the pressure-receiving part 17 rotates under pressure. After the pressure-receiving part 17 rotates 90°, it is blocked by the blocking part 18. The pressure-receiving part 17 drives the rotating ball 11 to rotate 90°, and the torsion spring between the rotating ball 11 and the adjacent trigger sleeve 5 twists.

[0047] After the rotating ball 11 rotates 90°, the axis of the first channel 1101 is collinear with the axis of the recovery channel 501. The recovery rod 502 continues to move rightward through the first channel 1101. When the recovery rod 502 passes through all the recovery channels 501, the elastic telescopic plate on the recovery rod 502 catches the right edge of the rightmost trigger sleeve 5. The operator pulls it out to take out all the trigger sleeves 5. Without using soluble balls and without having to calculate in advance the precise dissolution time of the soluble balls and the time required for fracturing, the recovery and reuse of all the trigger sleeves 5 can be achieved.

[0048] Those skilled in the art of this industry should understand that the above embodiments do not limit the present invention in any form. Any technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A hydraulic self-locking circulating valve for oilfield exploitation, comprising a plurality of positioning sleeves (1) arranged in a straight line and all disposed in an oil well. The positioning sleeve (1) is provided with a communication hole (2). Connecting sleeves (3) are installed on both sides of the positioning sleeve (1). An inner sliding sleeve (4) is slidably connected in the positioning sleeve (1). The inner sliding sleeve (4) is used to block the adjacent communication hole (2). A first elastic member is fixedly connected between the inner sliding sleeve (4) and the adjacent positioning sleeve (1). The inner sliding sleeve (4) is slidably connected with a trigger sliding sleeve (5). The trigger sliding sleeve (5) is provided with a recovery channel (501). All the positioning sleeves (1) and all the connecting sleeves (3) are jointly provided with a recovery rod (502) for recovering all the trigger sliding sleeves (5), characterized in that, The trigger sliding sleeve (5) is slidably connected with a first sliding ring (6) and a second sliding ring (7). A limiting portion (503) for blocking the adjacent second sliding ring (7) is arranged in the inner sliding sleeve (4). A plurality of elastic support bars (8) evenly distributed in the circumferential direction are fixedly connected between the first sliding ring (6) and the adjacent second sliding ring (7). When the elastic support bars (8) are located in the adjacent inner sliding sleeve (4), the elastic support bars (8) are straightened by the adjacent inner sliding sleeve (4). After the elastic support bars (8) are separated from the adjacent inner sliding sleeve (4), the middle parts of the elastic support bars (8) evenly distributed in the circumferential direction open outwards respectively.

2. The hydraulic self-locking circulation valve for oilfield exploitation according to claim 1, characterized in that, A soluble ball is installed in the recovery channel (501). From the wellhead to the bottom of the oil well, the inner diameters of all the inner sliding sleeves (4), the outer diameters of all the trigger sliding sleeves (5), the inner diameters of all the limiting portions (503), the outer diameters of all the first sliding rings (6) and the outer diameters of all the second sliding rings (7) decrease in sequence.

3. The hydraulic self-locking circulation valve for oilfield exploitation according to claim 1, wherein, A sealing ring (9) is fixedly connected to the second sliding ring (7), and the sealing ring (9) is attached to the adjacent limiting portion (503).

4. A hydraulic self-locking circulation valve for oilfield exploitation according to claim 1, wherein, A rotating ball (11) is rotatably connected in the trigger sliding sleeve (5). The rotating ball (11) is provided with a first channel (1101). The rotating ball (11) is used for blocking the recovery channel (501), and the first channel (1101) is used for communicating the recovery channel (501).

5. The hydraulic self-locking circulation valve for oilfield exploitation according to claim 4, wherein A second channel (12) is arranged in the trigger sliding sleeve (5). A pressing rod (13) is hermetically slidably connected in the second channel (12). A second elastic member is fixedly connected between the trigger sliding sleeve (5) and the adjacent pressing rod (13). The pressing rod (13) is used for pressing the adjacent first sliding ring (6).

6. The hydraulic self-locking circulation valve for oilfield exploitation according to claim 5, characterized in that The trigger sliding sleeve (5) is provided with a plurality of stepped portions (14) distributed linearly. The stepped portions (14) are used for limiting the elastic support bars (8).

7. A hydraulic self-locking circulation valve for oilfield exploitation according to claim 6, characterized in that, The inner diameter of the stepped portion (14) is larger than the inner diameter of the corresponding limiting portion (503), the inner diameter of the stepped portion (14) is smaller than the outer diameter of the corresponding first sliding ring (6), and the inner diameter of the stepped portion (14) is larger than the outer diameter of the corresponding second sliding ring (7). The stepped portion (14) of the trigger sliding sleeve (5) far from the limiting portion (503) is used for blocking the corresponding first sliding ring (6).

8. A hydraulic self-locking circulation valve for oilfield exploitation according to claim 7, characterized in that, A torsion spring is fixedly connected between the rotating ball (11) and the adjacent trigger sliding sleeve (5).

9. A hydraulic self-locking circulation valve for oilfield exploitation according to claim 8, characterized in that, The trigger sliding sleeve (5) is provided with a third channel (15). A blocking ring (16) for blocking the third channel (15) is slidably connected in the trigger sliding sleeve (5). A plurality of elastic telescopic plates distributed circumferentially are slidably connected to the recovery rod (502). The blocking ring (16) is provided with a groove for the elastic telescopic plate of the recovery rod (502) to enter. The rotating ball (11) is provided with a pressure-receiving part (17) located in the third channel (15). A blocking part (18) for blocking adjacent pressure-receiving parts (17) is arranged in the third channel (15).

10. A hydraulic self-locking circulation valve for oilfield exploitation according to claim 9, characterized in that, The contact surfaces between the blocking ring (16) and the adjacent trigger sliding sleeve (5) are all friction surfaces. The frictional resistance when the blocking ring (16) slides is A, and the acting force required for the elastic telescopic plate on the recovery rod (502) to be compressed is B, and A < B.

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