Petroleum operation toe end sliding sleeve capable of being opened in delayed mode

Abstract

The invention belongs to the technical field of oil exploitation, and particularly relates to a toe-end sliding sleeve capable of being opened in a delayed mode and used for oil operation, the toe-end sliding sleeve comprises an upper connector and a lower connector, an external cylinder assembly and an internal cylinder assembly are connected between the upper connector and the lower connector, and a sliding cavity is reserved between the external cylinder assembly and the internal cylinder assembly; the external cylinder assembly comprises an outer cylinder and outward sand blasting holes formed in the outer cylinder, and the internal cylinder assembly comprises an inner cylinder and inward sand blasting holes formed in the inner cylinder. The outward thin films and the inward thin films are mounted on the outward sides of the outward sand blasting holes and the inward sides of the inward sand blasting holes correspondingly, and cement paste is prevented from entering the outward sand blasting holes and the inward sand blasting holes through the outward thin films and the inward thin films; the hollow plugs support the outward film and the inward film by being inserted into the outward sand blasting holes and the inward sand blasting holes, so that the outward film and the inward film are prevented from being crushed by slurry inside the inner cylinder and outside the outer cylinder.

Description

Technical Field

[0001] This invention belongs to the field of oil extraction technology, and specifically relates to a toe-end sliding sleeve for oil operations that can be opened with a delay. Background Technology

[0002] The toe-end fracturing sleeve is a key piece of equipment in downhole fracturing operations. Its structure mainly consists of an inner cylinder, an outer cylinder, and a sleeve located between the two. The main function of the sleeve is to seal the blasting holes on the inner and outer cylinders, thereby effectively blocking fluid flow between the two cylinders. Once the sleeve moves under external force, allowing the blasting holes to connect, the fracturing operation can proceed smoothly.

[0003] The existing toe-end fracturing sleeve has the following technical problems when used. First, before fracturing operations, when the sliding sleeve blocks the blasting holes of both cylinders, cement slurry in the inner cylinder can easily deposit inside the blasting holes. If the blasting holes are completely blocked by cement, the sliding sleeve may not be able to open in time according to the design pressure, affecting the establishment of the fracturing channel. The existing technical solution is to place a pre-placed spacer ring of soluble material on the blasting holes of the inner cylinder to block the mud, such as the invention patent with publication number CN113803024B. However, as the spacer ring dissolves, the blasting holes will still be exposed, which cannot fundamentally solve the problem of the blasting holes being blocked by cement.

[0004] Secondly, during fracturing operations, the sliding sleeve is driven to move by the increased pressure difference between the inner and outer cylinders, and the cavity between the inner and outer cylinders is connected to the blasting hole. Furthermore, to prevent malfunction of the sliding sleeve during wellbore pressure testing, multiple shear pins are typically used to fix the sliding sleeve to the inner or outer cylinder, as described in invention patent publication number CN115247546B. However, the shearing fracturing of these shear pins often has an error of about 15%, increasing the gap between the sliding sleeve and the cavity, allowing cement slurry to easily seep in, hindering the sliding movement of the sleeve, and making it difficult to open. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a delayed-opening toe sleeve for oil operations, thereby solving the technical problems in the prior art.

[0006] The objective of this invention can be achieved through the following technical solution: a toe-end sliding sleeve for oilfield operations capable of delayed opening, comprising an upper connector and a lower connector, wherein an external cylinder assembly and an internal cylinder assembly are respectively connected between the upper and lower connectors, and a sliding cavity is reserved between the external cylinder assembly and the internal cylinder assembly; the external cylinder assembly includes an outer cylinder and outward sandblasting holes formed on the outer cylinder, and the internal cylinder assembly includes an inner cylinder and inward sandblasting holes formed on the inner cylinder; a hollow sliding sleeve is slidably installed in the sliding cavity, a constant pressure ignition assembly is installed in the sliding cavity, and a spacer assembly is installed on the hollow sliding sleeve. The hollow sleeve has a transmission component that is slidably installed inside, and the constant pressure ignition component drives the transmission component to move. The diaphragm component includes a hollow plug and a push plate that is slidably installed inside the hollow plug. The hollow plug is inserted into the outward sandblasting hole and the inward sandblasting hole. An outward film and an inward film are respectively installed on the outward sandblasting hole and the inward sandblasting hole. The transmission component includes a pull ring, an annular plate is installed on the pull ring, the annular plate is connected to the push plate through a connecting rod, a pin is installed on the push plate, a pin hole is opened on the hollow plug, and the pin passes through the pin hole and pierces the edge of the outward film and the inward film.

[0007] As a further optimization or improvement of this solution, an inclined ring platform is installed on the annular plate, and a sealing assembly is installed on the hollow sliding sleeve. The sealing assembly includes a sealing ring gasket, and an inclined platform is installed on the inner side of the sealing ring gasket. The inclined ring platform and the inclined platform cooperate with each other.

[0008] As a further optimization or improvement of this solution, a baffle is installed inside the sliding cavity, and the baffle is connected to the external cylinder assembly and the internal cylinder assembly respectively. The constant pressure ignition assembly includes a triggering mechanism, which is connected to an electronic ignition device through a wiring harness. An explosive chamber is reserved inside the sliding cavity and filled with explosive material. A push ring is installed on the pull ring, and the push ring and pull ring are moved by igniting the constant pressure ignition assembly.

[0009] As a further optimization or improvement to this solution, a buffer pad is installed on the hollow sliding sleeve. When the hollow sliding sleeve hits the baffle, the buffer pad provides cushioning.

[0010] As a further optimization or improvement to this solution, a guide post is installed on the pull ring, and the guide post slides in conjunction with the hollow sliding sleeve.

[0011] As a further optimization or improvement of this solution, an anti-sticking material is sprayed onto the outward and inward films.

[0012] The beneficial effects of this invention are: (1) Before fracturing, the hollow sliding sleeve blocks the outward and inward sandblasting holes on the outer and inner cylinders. In this invention, an outward membrane and an inward membrane are installed on the outward side of the outward sandblasting hole and the inward side of the inward sandblasting hole, respectively. The outward and inward membranes prevent cement slurry from entering the outward and inward sandblasting holes. At the same time, the hollow plug supports the outward and inward membranes by inserting it into the outward and inward sandblasting holes, so as to prevent the mud inside the inner cylinder and outside the outer cylinder from crushing the outward and inward membranes.

[0013] (2) During fracturing operations, the constant pressure ignition assembly drives the pull ring to move axially. The pull ring first pushes the push plate to move through the connecting rod, so that the pin on the push plate passes through the pin hole on the hollow plug and pierces the edge of the outward and inward films. As the pull ring moves, the push plate drives the hollow plug to move synchronously. The hollow plug pushes the entire outward and inward films out of the outward and inward sandblasting holes, avoiding the outward and inward films from being stuck inside the outward and inward sandblasting holes and obstructing the flow of fluid. The fluid flow rate is reduced, which can easily cause the outward and inward films to become blocked.

[0014] (3) During fracturing operations, the pull ring drives the hollow sliding sleeve to move, and the outward sandblasting hole and the inward sandblasting hole are connected. When the hollow sliding sleeve contacts the baffle, the hollow sliding sleeve stops moving. At this time, as the pull ring continues to move, the pull ring drives the inclined ring platform to move synchronously. The inclined ring platform compresses the sealing ring gasket through the inclined platform to fill the gap between the hollow sliding sleeve and the sliding cavity, preventing cement slurry from seeping into the sliding cavity through the gap between the hollow sliding sleeve and the sliding cavity, hindering the sliding movement of the sliding sleeve, and causing difficulty in opening the sliding sleeve. Furthermore, as the inclined ring platform compresses the sealing ring gasket, the resistance between the hollow sliding sleeve and the sliding cavity increases, thereby inhibiting the movement of the pull ring and preventing the constant pressure ignition assembly from generating extremely strong shock waves that could damage the components around the transmission assembly, thus affecting the normal extraction of oil and gas. Attached Figure Description

[0015] The invention will now be further described with reference to the accompanying drawings.

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0017] Figure 2 This is a schematic diagram of the disassembled structure of the present invention.

[0018] Figure 3 This is a cross-sectional view of the overall structure of the present invention.

[0019] Figure 4 for Figure 3 Enlarged view of the structure of part A.

[0020] Figure 5 for Figure 3 Enlarged view of the structure of part B.

[0021] Figure 6 This is a schematic diagram of the internal structure of the sliding cavity.

[0022] Figure 7 This is a diagram showing the fit between the hollow sliding sleeve and the transmission assembly.

[0023] Figure 8 This is a schematic diagram of the overall structure of the transmission assembly.

[0024] The diagram shows: 1. Upper connector; 2. Lower connector; 3. External cylinder assembly; 301. Outer cylinder; 302. Outward sandblasting hole; 303. Outward membrane; 4. Internal cylinder assembly; 401. Inner cylinder; 402. Inward sandblasting hole; 403. Inward membrane; 5. Hollow sliding sleeve; 6. Transmission assembly; 601. Pull ring; 602. Inclined ring platform; 603. Annular plate; 604. Guide post; 605. 7. Push ring; 8. Divider assembly; 9. Hollow plug; 10. Pinhole; 11. Push plate; 2. Ejector pin; 3. Connecting rod; 4. Sealing assembly; 5. Sealing ring gasket; 6. Inclined platform; 7. Constant pressure ignition assembly; 8. Triggering mechanism; 9. Wiring harness; 12. Electronic ignition device; 13. Explosive chamber; 14. Buffer pad; 15. Baffle; 16. Sliding cavity. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] See Figures 1-8A delayed-opening toe sleeve for oilfield operations includes an upper connector 1 and a lower connector 2, with an outer cylinder assembly 3 and an inner cylinder assembly 4 respectively connected between the upper connector 1 and the lower connector 2, and a pre-reserved sliding cavity 12 between the outer cylinder assembly 3 and the inner cylinder assembly 4; the outer cylinder assembly 3 includes an outer cylinder 301 and outward sandblasting holes 302 formed on the outer cylinder 301, and the inner cylinder assembly 4 includes an inner cylinder 401 and inward sandblasting holes 402 formed on the inner cylinder 401; a hollow sliding sleeve 5 is slidably installed in the sliding cavity 12, a constant pressure ignition assembly 9 is installed in the sliding cavity 12, a partition assembly 7 is installed on the hollow sliding sleeve 5, and a transmission assembly 6 is slidably installed inside the hollow sliding sleeve 5, driving the constant pressure ignition assembly 9. The transmission assembly 6 moves; the diaphragm assembly 7 includes a hollow plug 701 and a push plate 703 slidably installed inside the hollow plug 701, and the hollow plug 701 is inserted into the outward sandblasting hole 302 and the inward sandblasting hole 402. The outward sandblasting hole 302 and the inward sandblasting hole 402 are respectively installed with an outward film 303 and an inward film 403. The transmission assembly 6 includes a pull ring 601, and an annular plate 603 is installed on the pull ring 601. The annular plate 603 is connected to the push plate 703 through a connecting rod 705. A pin 704 is installed on the push plate 703. A pin hole 702 is opened on the hollow plug 701, and the pin 704 passes through the pin hole 702 and pokes the edges of the outward film 303 and the inward film 403.

[0027] Specifically, a baffle 11 is installed inside the sliding cavity 12, and the baffle 11 is connected to the external cylinder assembly 3 and the internal cylinder assembly 4 respectively. The constant pressure ignition assembly 9 includes a triggering mechanism 901, which is connected to an electronic ignition device 903 through a wiring harness 902. An explosive chamber 904 is reserved inside the sliding cavity 12 and filled with explosive material. A push ring 605 is installed on the pull ring 601. The push ring 605 and the pull ring 601 are moved by igniting the constant pressure ignition assembly 9.

[0028] It should be noted that the pinhole 702 and the ejector pin 704 are arranged in a circle, and the pinhole 702 corresponds to the ejector pin 704.

[0029] It should be noted that before fracturing operations, please refer to... Figures 4-6 The hollow sliding sleeve 5 blocks the outward sandblasting holes 302 and 402 on the outer cylinder 301 and inner cylinder 401. In this invention, an outward membrane 303 and an inward membrane 403 are respectively installed on the outward side of the outward sandblasting hole 302 and the inward side of the inward sandblasting hole 402. The outward membrane 303 and the inward membrane 403 prevent cement slurry from entering the outward sandblasting hole 302 and the inward sandblasting hole 402. At the same time, the hollow plug 701 supports the outward membrane 303 and the inward membrane 403 by inserting it into the outward sandblasting hole 302 and the inward sandblasting hole 402, so as to prevent the mud inside the inner cylinder 401 and the outside of the outer cylinder 301 from crushing the outward membrane 303 and the inward membrane 403.

[0030] See Figure 4 and Figure 8 An inclined annular platform 602 is installed on the annular plate 603, and a sealing component 8 is installed on the hollow sliding sleeve 5. The sealing component 8 includes a sealing ring gasket 801, and an inclined platform 802 is installed on the inner side of the sealing ring gasket 801. The inclined annular platform 602 and the inclined platform 802 cooperate with each other.

[0031] It should be noted that during fracturing operations, the hydraulic pressure inside the inner cylinder 401 increases, triggering the triggering mechanism 901 by external force to meet the triggering conditions, thereby activating the electronic ignition device 903, which detonates the explosive material in the explosive chamber 904. The pressure in the explosive chamber 904 increases rapidly, thereby pushing the push ring 605 and pull ring 601 to move axially.

[0032] The pull ring 601 first pushes the push plate 703 to move via the connecting rod 705. The push plate 703 slides along the inner cavity of the hollow plug 701, causing the ejector pin 704 on the push plate 703 to pass through the pin hole 702 on the hollow plug 701 and puncture the edges of the outward membrane 303 and the inward membrane 403. As the pull ring 601 moves, the push plate 703 drives the hollow plug 701 to move synchronously. The hollow plug 701 pushes the entire outward membrane 303 and the inward membrane 403 out of the outward blasting hole 302 and the inward blasting hole 402, thus preventing the outward membrane 303 and the inward membrane 403 from being stuck inside the outward blasting hole 302 and the inward blasting hole 402 and obstructing the flow of fluid. This reduces the fluid flow rate and makes it easier for the outward membrane 303 and the inward membrane 403 to become blocked. As the pull ring 601 continues to move, the pull ring 601 drives the push plate 703 to pull the hollow plug head 701 through the connecting rod 705. After the hollow plug head 701 is retracted into the hollow sliding sleeve 5, the pull ring 601 drives the hollow sliding sleeve 5 to move. As the hollow sliding sleeve 5 moves, the outward sandblasting hole 302 on the outer cylinder 301 is connected to the inward sandblasting hole 402 on the inner cylinder 401.

[0033] When the pull ring 601 moves the hollow sliding sleeve 5, the outward sandblasting hole 302 and the inward sandblasting hole 402 are connected. When the hollow sliding sleeve 5 contacts the baffle 11, the hollow sliding sleeve 5 stops moving. At this time, as the pull ring 601 continues to move, the pull ring 601 drives the inclined ring platform 602 to move synchronously. Through the cooperation between the inclined surface on the inclined ring platform 602 and the inclined platform 802, the inclined ring platform 602 compresses the sealing ring gasket 801 through the inclined platform 802, filling the gap between the hollow sliding sleeve 5 and the sliding cavity 12, preventing cement slurry from seeping into the sliding cavity 12 through the gap between the hollow sliding sleeve 5 and the sliding cavity 12, hindering the sliding movement of the sliding sleeve, and causing difficulty in opening the sliding sleeve. At the same time, as the inclined ring platform 602 compresses the sealing ring gasket 801, the resistance between the hollow sliding sleeve 5 and the sliding cavity 12 increases, thereby inhibiting the movement of the pull ring 601, preventing the constant pressure ignition assembly 9 from generating extremely strong shock waves that damage the components around the transmission assembly 6, thereby affecting the normal extraction of oil and gas.

[0034] See Figure 6 A buffer pad 10 is installed on the hollow sliding sleeve 5. When the hollow sliding sleeve 5 hits the baffle 11, the buffer pad 10 provides cushioning.

[0035] Specifically, a guide post 604 is installed on the pull ring 601, and the guide post 604 is in sliding engagement with the hollow sliding sleeve 5.

[0036] Specifically, an anti-sticking material is sprayed onto the outward-facing film 303 and the inward-facing film 403.

[0037] It should be noted that, in order to buffer the impact of the hollow sliding sleeve 5 on the baffle 11 under the impact inertia of the constant pressure ignition assembly 9, a buffer pad 10 is installed on the hollow sliding sleeve 5. The buffer pad 10 buffers the impact between the hollow sliding sleeve 5 and the baffle 11. The guide post 604 is precisely matched with the hollow sliding sleeve 5 to improve the guiding accuracy of the hollow sliding sleeve 5 and the transmission assembly 6. The electronic ignition device 903 can also be controlled by a delay program to adapt to various operating conditions.

[0038] The implementation principle of this invention is as follows: Before fracturing operations, see Figures 4-6 The hollow sliding sleeve 5 blocks the outward sandblasting holes 302 and 402 on the outer cylinder 301 and inner cylinder 401. In this invention, an outward membrane 303 and an inward membrane 403 are respectively installed on the outward side of the outward sandblasting hole 302 and the inward side of the inward sandblasting hole 402. The outward membrane 303 and the inward membrane 403 prevent cement slurry from entering the outward sandblasting hole 302 and the inward sandblasting hole 402. At the same time, the hollow plug 701 supports the outward membrane 303 and the inward membrane 403 by inserting it into the outward sandblasting hole 302 and the inward sandblasting hole 402, so as to prevent the mud inside the inner cylinder 401 and the outside of the outer cylinder 301 from crushing the outward membrane 303 and the inward membrane 403.

[0039] During fracturing operations, the hydraulic pressure inside the inner cylinder 401 increases, triggering the triggering mechanism 901 by external force to meet the triggering conditions, thereby activating the electronic ignition device 903 and detonating the explosive material in the explosive chamber 904. The pressure in the explosive chamber 904 increases rapidly, thereby pushing the push ring 605 and pull ring 601 to move axially. The pull ring 601 first pushes the push plate 703 to move via the connecting rod 705. The push plate 703 slides along the inner cavity of the hollow plug 701, causing the ejector pin 704 on the push plate 703 to pass through the pin hole 702 on the hollow plug 701 and puncture the edges of the outward membrane 303 and the inward membrane 403. As the pull ring 601 moves, the push plate 703 drives the hollow plug 701 to move synchronously. The hollow plug 701 pushes the entire outward membrane 303 and the inward membrane 403 out of the outward blasting hole 302 and the inward blasting hole 402, preventing the outward membrane 303 and the inward membrane 403 from being stuck inside the outward blasting hole 302 and the inward blasting hole 402 and obstructing the flow of fluid, which would reduce the flow rate and make it easier for the outward membrane 303 and the inward membrane 403 to become blocked. As the pull ring 601 continues to move, the pull ring 601 drives the push plate 703 to pull the hollow plug head 701 through the connecting rod 705. After the hollow plug head 701 is retracted into the hollow sliding sleeve 5, the pull ring 601 drives the hollow sliding sleeve 5 to move. As the hollow sliding sleeve 5 moves, the outward sandblasting hole 302 on the outer cylinder 301 is connected to the inward sandblasting hole 402 on the inner cylinder 401, and fracturing operations can be carried out.

[0040] When the pull ring 601 moves the hollow sliding sleeve 5, the outward sandblasting hole 302 and the inward sandblasting hole 402 are connected. When the hollow sliding sleeve 5 contacts the stop plate 11, the hollow sliding sleeve 5 stops moving. At this time, as the pull ring 601 continues to move, the pull ring 601 drives the inclined ring platform 602 to move synchronously. Through the cooperation between the inclined surface on the inclined ring platform 602 and the inclined platform 802, the inclined ring platform 602 compresses the sealing ring gasket 801 through the inclined platform 802, filling the gap between the hollow sliding sleeve 5 and the sliding cavity 12. The gap created between the hollow sliding sleeve 5 and the sliding cavity 12 prevents cement slurry from seeping into the sliding cavity 12 through the gap, hindering the sliding movement of the sliding sleeve and making it difficult to open the sliding sleeve; at the same time, as the inclined ring platform 602 compresses the sealing ring gasket 801, the resistance between the hollow sliding sleeve 5 and the sliding cavity 12 increases, thereby inhibiting the movement of the pull ring 601, and preventing the constant pressure ignition assembly 9 from generating extremely strong shock waves that could damage the pull ring 601 and the surrounding components of the transmission assembly 6, thereby affecting the normal extraction of oil and gas.

[0041] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A toe-end sliding sleeve for oilfield operations capable of delayed opening, characterized in that: It includes an upper connector (1) and a lower connector (2), with an external cylinder assembly (3) and an internal cylinder assembly (4) respectively connected between the upper connector (1) and the lower connector (2), and a sliding cavity (12) reserved between the external cylinder assembly (3) and the internal cylinder assembly (4); the external cylinder assembly (3) includes an outer cylinder (301) and an outward sandblasting hole (302) opened on the outer cylinder (301), and the internal cylinder assembly (4) includes an inner cylinder (401) and an inward sandblasting hole (402) opened on the inner cylinder (401); A hollow sliding sleeve (5) is slidably installed inside the sliding cavity (12). A constant pressure ignition assembly (9) is installed inside the sliding cavity (12). A diaphragm assembly (7) is installed on the hollow sliding sleeve (5). A transmission assembly (6) is slidably installed inside the hollow sliding sleeve (5). The constant pressure ignition assembly (9) drives the transmission assembly (6) to move. The diaphragm assembly (7) includes a hollow plug (701) and a push plate (703) slidably installed inside the hollow plug (701). The hollow plug (701) is inserted into the outward sandblasting hole (302) and the inward sandblasting hole (402). Outward blasting hole (302) and inward blasting hole (402) are respectively installed with outward diaphragm (303) and inward diaphragm (403). The transmission assembly (6) includes a pull ring (601), an annular plate (603) is installed on the pull ring (601), the annular plate (603) is connected to the push plate (703) through the connecting rod (705), the push plate (703) is installed with a pin (704), the hollow plug (701) has a pin hole (702), and the pin (704) passes through the pin hole (702) and pokes the edges of the outward diaphragm (303) and the inward diaphragm (403).

2. The toe sleeve for oilfield operations capable of delayed opening according to claim 1, characterized in that: An inclined ring platform (602) is installed on the annular plate (603), and a sealing assembly (8) is installed on the hollow sliding sleeve (5). The sealing assembly (8) includes a sealing ring gasket (801), and an inclined platform (802) is installed on the inner side of the sealing ring gasket (801). The inclined ring platform (602) cooperates with the inclined platform (802).

3. The toe sleeve for oilfield operations capable of delayed opening according to claim 1, characterized in that: The slide cavity (12) is equipped with a baffle (11), which is connected to the external cylinder assembly (3) and the internal cylinder assembly (4) respectively. The constant pressure ignition assembly (9) includes a triggering mechanism (901), which is connected to an electronic ignition device (903) through a wire harness (902). The slide cavity (12) has a reserved explosive chamber (904), which is filled with explosive material. The pull ring (601) is equipped with a push ring (605), which is pushed by igniting the constant pressure ignition assembly (9).

4. A toe-end sliding sleeve for oilfield operations capable of delayed opening according to claim 1, characterized in that: A buffer pad (10) is installed on the hollow sliding sleeve (5). When the hollow sliding sleeve (5) hits the baffle (11), the buffer pad (10) provides cushioning.

5. A toe-end sliding sleeve for oilfield operations capable of delayed opening according to claim 1, characterized in that: The pull ring (601) is equipped with a guide post (604), and the guide post (604) slides in conjunction with the hollow sliding sleeve (5).

6. A toe-end sliding sleeve for oilfield operations capable of delayed opening according to claim 1, characterized in that: Anti-sticking material is sprayed onto the outward-facing film (303) and the inward-facing film (403).

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