Closeable two-stage sliding sleeve sandblaster and fracturing method capable of lifting down pipe string under pressure

Abstract

The present application relates to a closable two-stage sliding sleeve sandblaster and a fracturing method capable of lifting a pipe column under pressure, which comprises a main pipe, an outer sliding sleeve, an inner sliding sleeve and a joint; the main pipe: the bottom end is fixedly connected to the top end of the joint, the two are coaxially arranged, and a main pipe port is provided on the side wall to directly connect the outside with the inside; the outer sliding sleeve: the coaxial line is inserted into the inside of the main pipe, and an outer pipe port is provided on the side wall to directly connect the outside with the inside, a shearing piece for fixing the outer sliding sleeve is provided on the main pipe, and the outer pipe port and the main pipe port are located on the same side of the outer sliding sleeve; the inner sliding sleeve: the coaxial line is inserted into the inside of the outer sliding sleeve, and a shearing piece for fixing the inner sliding sleeve is provided on the outer sliding sleeve; the joint: the bottom end is closed, the inside is connected to the inside of the main pipe through and the top end of the joint, and the joint is provided with spaces for accommodating the inner sliding sleeve and the outer sliding sleeve respectively, and when the outer sliding sleeve is located in the joint, the side wall of the outer sliding sleeve covers and closes the main pipe port. The present application has the effect of being able to achieve the effect of lifting a pipe column under pressure.

Description

Technical Field

[0001] This application relates to the field of oil fracturing equipment, and in particular to a shut-off two-stage sliding sleeve sandblaster and a fracturing method capable of raising and lowering the tubing string under pressure. Background Technology

[0002] After oil wells reach a certain production stage, their productivity and permeability decrease. To enhance oil drainage capacity and increase well production, fracturing technology was invented. Fracturing methods are broadly classified into hydraulic fracturing and high-energy gas fracturing. Hydraulic fracturing involves injecting fluid at high speed into the well using a surface high-pressure pump truck. The high pressure generated at the bottom of the well causes the oil-bearing rock to fracture, creating fissures. To prevent the fractures from closing automatically after the pump truck stops operating and the pressure drops, sand with a density several times greater than the formation is mixed into the injected fluid after the formation fractures. This sand enters the fractures along with the fluid and remains permanently within them, keeping the fractures open and ensuring a long-term improved oil flow environment. During fracturing to obtain oil, casing is laid in the production area, and packers are used to separate and seal oil layers at different depths. During oil fracturing, the production tubing is connected above the uppermost packer to drain the oil from the formation to the outside.

[0003] During the development of oil and gas fields, as the gas production time of gas wells increases, the presence of various corrosive gases, such as those containing H2S and CO2, causes problems such as corrosion of oil tubing, leakage of tubing threads, and leakage of downhole tool strings in some oil and gas wells. Therefore, it is necessary to replace the production tubing string in the well. In the process of replacing tubing under pressure, the tubing passage is generally sealed by using plugs or bridge plugs.

[0004] Regarding the aforementioned technologies, the inventors believe that when there are multiple points of leakage in the inner diameter of the tubing or when the tubing wall is irregular, it is impossible to insert tubing bridge plugs and plugs to seal the tubing; when the tubing is suspended by an upper flange, the wellhead cannot be disassembled because the casing annulus is not sealed, and therefore pressurized operations cannot be performed. Summary of the Invention

[0005] In order to enable the pressurized lowering of the tubing string, this application provides a shut-off two-stage sliding sleeve sandblasting device.

[0006] This application provides a shut-off two-stage sliding sleeve sandblasting device, which adopts the following technical solution:

[0007] A shut-off two-stage sliding sleeve sandblasting device includes a main tube, an outer sliding sleeve, an inner sliding sleeve, and a connector;

[0008] Main tube: The bottom end is fixedly connected to the top end of the connector, and the two are coaxially arranged. A main pipe port is opened on the side wall to directly connect the outside and the inside. Outer sleeve: It is coaxially inserted into the inside of the main tube. An outer pipe port is opened on the side wall to directly connect the outside and the inside. The main tube is provided with a shear member to fix the outer sleeve. The outer pipe port and the main pipe port are located on the same side of the outer sleeve. Inner sleeve: It is coaxially inserted into the inside of the outer sleeve. A shear member is provided on the outer sleeve to fix the inner sleeve. Connector: The bottom end is closed. The inside and the top end of the connector are connected to the inside of the main tube. The connector is provided with spaces for accommodating the inner sleeve and the outer sleeve respectively. When the outer sleeve is located in the connector, the side wall of the outer sleeve covers and closes the main pipe port.

[0009] By adopting the above technical solution, the solution described in this application belongs to the component connected to the bottom of the packer. In actual use, after the packer is set by the sealing ball and external pressure, the sealing ball will fall on the top of the inner sliding sleeve and apply downward pressure to the inner sliding sleeve under the pressure of continued external supply, so that the inner sliding sleeve has a downward movement tendency until the pressure applied by the outside will break the shear member connected to the inner sliding sleeve. The inner sliding sleeve will move downward and no longer cover the main pipe port and the outer pipe port. At this time, the formation pressure can carry the oil in the formation to flow into the production tubing. When it is necessary to remove the production tubing, simply connect the outer tube port of the upper layer to the main tube port. The inner sleeve of the upper layer will fall on top of the outer sleeve of the lower layer. Since the inner sleeve that falls still carries the sealing ball that seals it, the external pressure will cause the outer sleeve that is against the inner sleeve of the upper layer to move downward. When the shear pin that fixes the outer sleeve is crushed, the outer sleeve will move downward into the joint. At the same time, the outer tube port will be covered and sealed by the inner wall of the main tube, and the main tube port will be covered and sealed by the side wall of the outer sleeve. This will seal this layer, and the pressure of this layer will no longer enter the production tubing through the main tube port and the outer tube port. In this way, the tubing can be removed under pressure.

[0010] Optionally, the shearing element includes shear studs.

[0011] By adopting the above technical solutions, the shear nail structure is simple and widely available. At the same time, it is divided into different categories according to the pressure required for its breakage, which makes it convenient for staff to select.

[0012] Optionally, a locking block is slidably connected to the side wall of the outer sliding sleeve along its radial direction. One end of the locking block abuts against the outer wall of the inner sliding sleeve, and the other end abuts against the inner wall of the main tube. A guide slope is provided on the side wall of the locking block, and the top end of the connector abuts against the guide slope and applies pressure to the locking block in the direction of the inner sliding sleeve.

[0013] By adopting the above technical solution, the locking block can hinder the downward movement of the outer sliding sleeve when the sealing ball applies a downward thrust to the inner sliding sleeve, so that the outer sliding sleeve can only slide downward when the inner sliding sleeve slides down until it no longer abuts the locking block, which can improve the stability of the outer sliding sleeve when the inner sliding sleeve slides downward.

[0014] Optionally, the connector includes a lower connector fixedly connected to the main tube and a sealing connector fixedly disposed at the bottom end of the lower connector. The inner wall of the lower connector is provided with a stepped surface for receiving the outer sliding sleeve, and the inner wall of the sealing connector is provided with a stepped surface for receiving the inner sliding sleeve.

[0015] By adopting the above technical solution, the inner and outer sliding sleeves can be supported by the lower joint and the sealing joint. At the same time, after fracturing, they can be taken out of the well along with the production tubing, packer, etc., for easy recovery.

[0016] Optionally, the inner wall of the outer sleeve is provided with a sealing ring that abuts against the outer wall of the inner sleeve.

[0017] By adopting the above technical solution, the sealing ring can enhance the sealing performance between the outer and inner sliding sleeves, and reduce the possibility of casing pressure leaking to the upper formation or even the ground through the gap between the outer and inner sliding sleeves.

[0018] Optionally, a sealing ring is provided on the inner wall of the main tube, which abuts against the outer wall of the outer sleeve.

[0019] By adopting the above technical solution, the sealing ring can enhance the sealing performance between the main pipe and the outer sliding sleeve, and reduce the possibility of casing pressure leaking to the upper strata or even the ground through the gap between the outer and inner sliding sleeves.

[0020] Optionally, the outer wall of the outer sleeve is provided with a retaining spring that abuts against the inner wall of the main tube.

[0021] By adopting the above technical solution, the snap ring can abut against the inner wall of the joint after the outer sliding sleeve moves into the joint, reducing the tendency of the outer sliding sleeve to move upward, so that the main pipe port and the outer pipe port are stably sealed.

[0022] Optionally, the outer wall of the inner sliding sleeve is provided with a retaining spring that abuts against the inner wall of the outer sliding sleeve.

[0023] By adopting the above technical solution, the snap ring can abut against the inner wall of the connector after the inner sliding sleeve moves into the connector, reducing the tendency of the inner sliding sleeve to move upward and ensuring stable connection between the main pipe port and the outer pipe port.

[0024] In summary, this application includes at least one of the following beneficial technical effects:

[0025] 1. The solution described in this application is a component connected to the bottom of the packer. In actual use, after the packer is set by the sealing ball and external pressure, the sealing ball will fall on the top of the inner sliding sleeve and apply downward pressure to the inner sliding sleeve under the continued external pressure, so that the inner sliding sleeve has a downward movement tendency until the external pressure breaks the shear member connected to the inner sliding sleeve. The inner sliding sleeve will move downward and no longer cover the main pipe port and the outer pipe port. At this time, the formation pressure can carry the oil in the formation into the production tubing. When it is necessary to remove the production tube column, simply connect the outer tube port of the upper layer to the main tube port. The inner sleeve of the upper layer will fall on the top of the outer sleeve of the lower layer. Since the inner sleeve that falls still carries the sealing ball that seals it, the external pressure will cause the outer sleeve that is against the inner sleeve of the upper layer to move downward. When the shear pin that fixes the outer sleeve is crushed, the outer sleeve will move downward into the joint. At the same time, the outer tube port will be covered and sealed by the inner wall of the main tube, and the main tube port will be covered and sealed by the side wall of the outer sleeve. This will seal this layer, and the pressure of this layer will no longer enter the production tube column through the main tube port and the outer tube port. In this way, the tube column can be lifted and lowered under pressure.

[0026] 2. The locking block can hinder the downward movement of the outer sliding sleeve when the sealing ball applies a downward thrust to the inner sliding sleeve. This means that the outer sliding sleeve can only slide downward when the inner sliding sleeve slides down until it no longer abuts the locking block, which can improve the stability of the outer sliding sleeve when the inner sliding sleeve slides downward. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of Example 1.

[0028] Figure 2 This is a schematic diagram in Embodiment 1 showing the connection state between the outer pipe port and the main pipe port.

[0029] Figure 3 This is a schematic diagram of the locking block structure shown in Embodiment 1.

[0030] Figure 4 This is a schematic diagram illustrating the lower connector structure in Embodiment 1.

[0031] Figure 5 This is a schematic diagram illustrating the structure of the sealing joint in Implementation 1.

[0032] Explanation of reference numerals in the attached drawings: 1. Main tube; 11. Main tube opening; 12. First shear pin; 13. First snap ring; 2. Outer sleeve; 21. Outer tube opening; 22. Second shear pin; 23. Second snap ring; 3. Sealing ball; 4. Inner sleeve; 5. Locking block; 6. Connector; 61. Lower connector; 611. First slot; 62. Sealing connector; 621. Second slot. Detailed Implementation

[0033] The present application will be further described in detail below with reference to the accompanying drawings.

[0034] Example 1:

[0035] This application discloses a shut-off dual-stage sliding sleeve sandblasting device. See also... Figure 1 and Figure 2 The system includes a main tube 1, an outer sliding sleeve 2, an inner sliding sleeve 4, and a connector 6. The connector 6 includes a lower connector 61 coaxially fixed to the main tube 1 and a sealing connector 62 coaxially fixed to the lower connector 61. In other embodiments, the sealing connector 62 and the lower connector 61 can also be threaded together. The main tube 1, outer sliding sleeve 2, inner sliding sleeve 4, lower connector 61, and sealing connector 62 are interconnected. Since this embodiment simulates fracturing of the lowest formation, the end of the sealing connector 62 facing away from the main tube 1 is sealed to ensure stable release of formation pressure through the production tubing. In other embodiments, such as during fracturing of a three-layer formation, the bottom end of the packer in the intermediate formation is connected to the top end of the main tube 1. In this case, the sealing connector 62 is not required; instead, the lower connector 61 is directly used to connect to the packer of the next formation.

[0036] The outer sliding sleeve 2 is fitted onto the inner sliding sleeve 4, and the main body tube 1 is fitted onto the outer sliding sleeve 2. The outer sliding sleeve 2 has an outer tube opening 21 that penetrates the side wall in a radial direction. The main body tube 1 has a main tube opening 11 that penetrates the side wall in a radial direction. The main tube opening 11 and the outer tube opening 21 are located on the same side of the outer sliding sleeve 2. By sliding the outer sliding sleeve 2 along the axial direction of the main body tube 1, the main tube opening 11 and the outer tube opening 21 can be made coaxial and connected. By sliding the inner sliding sleeve 4 along the axial direction of the main body tube 1, the inner sliding sleeve 4 can cover and close the outer tube opening 21.

[0037] See Figure 2 and Figure 3 In other embodiments, the inner wall of the outer sliding sleeve 2 is provided with a sealing ring that abuts against the outer wall of the inner sliding sleeve 4, and the inner wall of the main tube 1 is provided with a sealing ring that abuts against the outer wall of the outer sliding sleeve 2.

[0038] See Figure 3 and Figure 4A first shear pin 12 is fixedly installed on the inner wall of the main tube 1. The first shear pin 12 penetrates the side wall of the main tube 1 and is fixedly connected to the outer sliding sleeve 2. The outer sliding sleeve 2 is fixed to the main tube 1 by the first shear pin 12, so that the outer tube opening 21 and the main tube opening 11 are coaxially connected. A second shear pin 22 is fixedly connected to the side wall of the outer sliding sleeve 2. The second shear pin 22 penetrates the side wall of the outer sliding sleeve 2 and is fixedly connected to the inner sliding sleeve 4. The inner sliding sleeve 4 is fixedly connected to the outer sliding sleeve 2 by the second shear pin 22, while covering and sealing the outer tube opening 21. After the packer is set and oil needs to be extracted, the sealing ball 3 used to set the packer will fall on the top of the inner sliding sleeve 4 and close the top port of the inner sliding sleeve 4. Pressure is applied to the space above the inner sliding sleeve 4 through the working tubing and the inside of the packer. The sealing ball 3 will drive the inner sliding sleeve 4 to move downward until the pressure breaks the first shear pin 12. The sealing ball 3 will carry the inner sliding sleeve 4 downward to the inside of the joint 6. At this time, the inner sliding sleeve 4 no longer covers the outer pipe port 21. The outer pipe port 21 is connected to the formation space through the main pipe port 11. At this time, the pressure in the production tubing is removed and the oil production equipment on the surface is turned on. The oil in the formation can be injected to the surface through the main pipe port 11, the outer pipe port 21, and the outer sliding sleeve 2 under the pressure inside the formation.

[0039] The top of the lower connector 61 has a stepped surface, making the top of the lower connector 61 constricted. The inner wall of the main body tube 1 has a stepped surface adapted to the top of the lower connector 61. A locking block 5 is slidably connected to the side wall of the outer sliding sleeve 2 along its radial direction. In this embodiment, a groove is opened on the outer wall of the outer sliding sleeve 2, and a countersunk groove is opened inside this groove to penetrate the outer wall of the outer sliding sleeve 2 radially. The structure of the locking block 5 is a steel block that is seamlessly inserted into the countersunk groove and welded to a steel block that is seamlessly inserted into the groove. When the first shear pin 12 and the second shear pin 22 are both intact, the two end faces of the locking block 5 abut against the outer wall of the inner sliding sleeve 4 and the inner wall of the main body tube 1, respectively. In this embodiment, the function of the locking block 5 is to reduce the possibility that the first shear pin 12 will break during the process of opening the inner sliding sleeve 4 by the sealing ball 3 and applying pressure, thereby causing the outer sliding sleeve 2 to move with the inner sliding sleeve 4 towards the lower connector 61. Therefore, a clearance groove is formed on the inner wall of the main tube 1. This clearance groove is located above the stepped surface of the main tube 1, allowing the top of the lower connector 61 to directly abut against the side wall of the locking block 5, and the end face of the locking block 5 to abut against the inside of this clearance groove. In this way, when the sealing ball 3 applies downward pressure to the inner sliding sleeve 4, although the outer sliding sleeve 2 also tends to move downward, the end of the locking block 5 abuts against the side wall of the inner sliding sleeve 4, and at the same time, the locking block 5 abuts against the top of the lower connector 61, so that neither the locking block 5 nor the outer sliding sleeve 2 can move downward until the inner sliding sleeve 4 moves downward and no longer abuts against the locking block 5. Only then can the locking block 5 move into the inner space of the outer sliding sleeve 2, and no longer abut against the top of the lower connector 61, allowing the outer sliding sleeve 2 to move downward. Consequently, the outer pipe opening 21 moves downward and is blocked and sealed by the inner wall of the main tube 1. This step is the process of sealing the formation pressure when it is necessary to lower the production tubing. In order to enable the locking block 5 to smoothly disengage from the top of the lower connector 61, the locking block 5 has an inclined surface at the end edge of the inner wall of the main tube 1. At the same time, the top of the lower connector 61 also has an inclined surface that matches this inclined surface. When the outer sliding sleeve 2 needs to move towards the lower connector 61, the locking block 5 can move more smoothly along the radial direction of the outer sliding sleeve 2, reducing the possibility that the top of the lower connector 61 will obstruct the movement of the locking block 5.

[0040] See Figure 3 and Figure 4 In other embodiments, a first retaining ring 13 is embedded on the bottom outer wall of the outer sliding sleeve 2, and a first retaining groove 611 adapted to the first retaining ring 13 is provided on the inner wall of the lower connector 61. That is, when the outer sliding sleeve 2 slides into the lower connector 61, the first retaining ring 13 on the outer sliding sleeve 2 can be locked in the first retaining groove 611, reducing the possibility of the outer sliding sleeve 2 moving towards the top of the main tube 1.

[0041] See Figure 3 and Figure 5In other embodiments, a second retaining ring 23 is embedded in the outer wall of the bottom end of the inner sliding sleeve 4, and a second retaining groove 621 adapted to the second retaining ring 23 is provided on the inner wall of the sealing joint 62. That is, when the inner sliding sleeve 4 moves into the sealing joint 62, the second retaining ring 23 on the inner sliding sleeve 4 will be locked in the second retaining groove 621, reducing the possibility of the inner sliding sleeve 4 moving towards the top of the main tube 1.

[0042] Example 2:

[0043] A fracturing method capable of raising and lowering a tubing string under pressure includes the following steps:

[0044] s1, After the packer is set, continue to pressurize until the sealing ball drives the inner sliding sleeve to move downwards and the inner sliding sleeve falls on the top of the outer sliding sleeve of the lower connector or the next layer of sandblasting device, so that the main pipe port is connected to the outer pipe port, thereby allowing the oil in the formation to be smoothly injected to the surface through the production tubing.

[0045] s2, when it is necessary to remove the production tube column, insert the sealing ball and apply pressure. The sealing ball drives the upper inner sliding sleeve to move downward to the top of the lower outer sliding sleeve. Continue to apply pressure to break the shear component that fixes the lower outer sliding sleeve. The upper inner sliding sleeve drives the lower outer sliding sleeve to move downward to the bottom of the main body. After the outer tube opening is blocked and sealed by the side wall of the main tube, the production tube column is removed.

[0046] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A closable two-stage sliding sleeve sandblaster, characterized in that: It comprises a main body tube (1), an outer sliding sleeve (2), an inner sliding sleeve (4) and a joint (6); The main body pipe (1): the bottom end is fixedly connected to the top end of the joint (6), the two are coaxially arranged, and a main pipe port (11) is opened on the side wall to directly connect the outside with the inside; The outer sleeve (2) is coaxially inserted into the main pipe (1), and an outer pipe opening (21) is provided on the side wall for directly connecting the outside with the inside. The main pipe (1) is provided with a shear member for fixing the outer sleeve (2), and the outer pipe opening (21) and the main pipe opening (11) are located on the same side of the outer sleeve (2); Inner sliding sleeve (4): the coaxial line is inserted into the inner part of the outer sliding sleeve (2), and the outer sliding sleeve (2) is provided with a shear member for fixing the inner sliding sleeve (4); The joint (6) has a closed bottom end, and the interior is connected to the interior of the main pipe (1) through the top end of the joint (6). The joint (6) is provided with spaces for accommodating the inner sleeve (4) and the outer sleeve (2). When the outer sleeve (2) is located in the joint (6), the side wall of the outer sleeve (2) covers and closes the main pipe opening (11); A locking block (5) is slidably connected to the side wall of the outer sleeve (2) in the radial direction thereof, one end of the locking block (5) abuts against the outer wall of the inner sleeve (4), and the other end abuts against the inner wall of the main tube (1); a guiding inclined surface is provided on the side wall of the locking block (5), and the top end of the joint (6) abuts against the guiding inclined surface and applies pressure on the locking block (5) in the direction of the inner sleeve (4); The joint (6) comprises a lower joint (61) fixedly connected to the main body tube (1) and a sealing joint (62) fixedly arranged at the bottom end of the lower joint (61); a step surface for receiving the outer sliding sleeve (2) is provided on the inner wall of the lower joint (61); and a step surface for receiving the inner sliding sleeve (4) is provided on the inner wall of the sealing joint (62).

2. The closable two-stage sliding sleeve sandblaster according to claim 1, characterized in that: The shear members include shear nails.

3. The closable two-stage sliding sleeve sandblaster according to claim 1, characterized in that: The inner wall of the outer sliding sleeve (2) is provided with a sealing ring which abuts against the outer wall of the inner sliding sleeve (4).

4. The closable two-stage sliding sleeve sandblaster according to claim 1, characterized in that: The inner wall of the main body tube (1) is provided with a sealing ring which abuts against the outer wall of the outer sliding sleeve (2).

5. The closable two-stage sliding sleeve sandblaster according to claim 1, characterized in that: A retaining spring abutting against the inner wall of the main tube (1) is provided on the outer wall of the outer sliding sleeve (2), and a groove for accommodating the retaining spring is provided on the inner wall of the joint (6).

6. The closable two-stage sliding sleeve sandblaster according to claim 1, characterized in that: A retaining spring abutting against the inner wall of the outer sliding sleeve (2) is provided on the outer wall of the inner sliding sleeve (4), and a groove for accommodating the retaining spring is provided on the inner wall of the joint (6).

7. A fracturing method capable of lifting a pipe string under pressure, characterized in that: The closable two-stage sliding sleeve sandblaster according to any one of claims 1 to 6 further comprises the following steps: s1, after the packer is set, continue to pressurize until the sealing ball drives the inner sleeve to move downward and the inner sleeve falls on the top of the outer sleeve of the lower joint or the next layer of sandblaster, so that the main pipe port is connected with the outer pipe port, so that the oil in the formation can be smoothly sprayed to the ground through the production string; s2. When it is necessary to lift and lower the production tubing, insert the sealing ball and apply pressure. The sealing ball drives the upper inner sleeve to move downward to the top of the lower outer sleeve. Continue to apply pressure to break the shear member fixing the lower outer sleeve. The upper inner sleeve drives the lower outer sleeve to move downward to the bottom of the main body. After the outer pipe opening is blocked and closed by the side wall of the main pipe, lift and lower the production tubing.

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