High-pressure water injection device with immovable string and double-turn layer change

Abstract

The utility model discloses an immovable string double-turn layer-changing high-pressure water injection device, which relates to the technical field of downhole tools, and comprises an outer cylinder, and the outer cylinder is provided with an upper water injection layer upper injection groove and an upper water injection layer lower injection groove from top to bottom; an upper sliding sleeve is arranged on the inner wall of the outer barrel at the position of the upper injection groove of the upper water injection layer, covers the upper injection groove of the upper water injection layer and is in breakable connection with the outer barrel; and the inner wall of the outer cylinder is provided with a conduction closing composite sleeve at the lower injection groove of the upper water injection layer. According to the utility model, a layered high-pressure water injection well with two different pressures or water injection layers needing to be changed alternately can be realized, a water injection tubular column does not need to be replaced by a layered pressure-driven water injection well through operation, and two-turn layer-changing water injection is realized by throwing balls at a wellhead.

Description

Technical Field

[0001] The utility model relates to the technical field of downhole tools, in particular to a high-pressure water injection device with double-round layer change and fixed pipe string. Background Art

[0002] In the water injection development of deep low-permeability and ultra-low-permeability reservoirs, water wells often fail to inject water and oil wells fail to produce oil. To address this problem, high-pressure water injection is often used. In recent years, pressure-driven water injection development technology has been developed. Pressure-driven water injection has higher injection pressures than high-pressure water injection. When high-pressure water injection wells or pressure-driven water injection wells have two layers (layer A and layer B) with different formation pressures or requiring different injection times, one layer needs to be injected with water while the other layer is not. The current method to achieve the change from injecting water into layer A and not injecting water into layer B in medium- and low-pressure water injection wells is to use a test vehicle, lower a salvage device into the injection pipe, and salvage the water distribution cores of the two layers, replace them, and then insert them into the corresponding water distributors. However, this method cannot be implemented in high-pressure water injection wells. Currently, another method to achieve water injection in one layer of an injection well while not injecting water in the other layer is to operate upstream. This requires brine to pressure the well, and all the layered injection pipes are pulled out, and then the injection pipes for the changed layer are lowered. This method requires a lot of equipment and a long operation time. The injection well needs to be stopped for a long time, which is costly.

[0003] Publication No. CN113356795B discloses a fracturing and sand control production sleeve and its application. The sleeve comprises a sleeve outer sleeve, a production sleeve, and a fracturing sleeve. The sleeve outer sleeve is provided with a series of fracturing channels I and a series of production channels II. Sand control screens are welded to the exterior of the production channels I. Upper and lower limit rings are located within the sleeve outer sleeve. The fracturing sleeve has a stepped cross-section, with the inner diameter of the upper section corresponding to the outer diameter of the production sleeve lower section, the inner diameter of the middle section being the same as the inner diameter of the production sleeve, and the lower section being a ball seat I. The upper section is provided with a series of fracturing channels II, which correspond one-to-one with the fracturing channels I on the sleeve outer sleeve during fracturing. The production sleeve has a stepped cross-section, with the upper section being a ball seat II and the middle section being provided with a series of production channels II, which correspond one-to-one with the production channels I on the sleeve outer sleeve during production. The outer diameter of the lower section is the same as the inner diameter of the upper section of the fracturing sleeve. The sleeve has a repeatable opening and closing function, facilitating subsequent stratified control or repeated fracturing operations.

[0004] The secondary ball-casting conduction solution of the prior art is ball dissolution, which is different from the present invention.

[0005] Announcement No.: CN212272147U discloses a carbon dioxide composite stratified injection device, including a stratified injection cylinder, in which a first-stage sliding sleeve and a second-stage sliding sleeve are sleeved, and the second-stage sliding sleeve is located above the first-stage sliding sleeve. The second-stage sliding sleeve can fix and block the top of the axial hole, or move down to expose the top of the axial hole and block the radial through hole at the same time; the device also includes a first-stage sealing ball and a second-stage sealing ball. The first-stage sealing ball can block the first-stage sliding sleeve, and the second-stage sealing ball can block the second-stage sliding sleeve.

[0006] The secondary ball-casting conduction solution of the prior art is a bypass fluid, which is similar to the present invention, but the implemented structure is different. The structure of the present invention has a larger flow rate.

[0007] Announcement No.: CN201420536Y, discloses a completion-type sliding sleeve fracturing valve including an upper joint, an upper sliding sleeve, a lower sliding sleeve, and a lower joint. A shear cap is installed at the left end of the space where the upper joint and the lower joint are connected and the upper sliding sleeve and the lower sliding sleeve are connected, and is fixed to the upper sliding sleeve with a shear nail 1. A claw spring is installed at the right end and is fixed to the lower sliding sleeve with a shear nail 2. Steel balls 1 and 2 are installed at the left ends of the upper sliding sleeve and the lower sliding sleeve to increase the oil flow channel, ensure normal fracturing of the upper layer, and knock down the upper sliding sleeve so that the two layers of tiles do not interfere with each other during completion production and do not affect the production of the lower layer.

[0008] The secondary pitching conduction solution of the prior art is to suppress the ball, which is different from the present invention.

[0009] In short, the technical solutions of the above-disclosed technologies, the technical problems to be solved and the beneficial effects produced are all different from those of the present utility model. Regarding the more technical features, technical problems to be solved and the beneficial effects of the present utility model, the above-disclosed technical documents do not provide any technical inspiration. Utility Model Content

[0010] In view of the above-mentioned defects in the prior art, the purpose of the present invention is to provide a high-pressure water injection device with double-round layer change and fixed pipe string.

[0011] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0012] The utility model provides a double-round layer-changing high-pressure water injection device with a fixed pipe column, comprising an outer cylinder, wherein the outer cylinder is provided with an upper injection groove of an upper water injection layer and a lower injection groove of an upper water injection layer from top to bottom; an upper sliding sleeve is provided on the inner wall of the outer cylinder at the upper injection groove of the upper water injection layer, the upper sliding sleeve covers the upper injection groove of the upper water injection layer, and the upper sliding sleeve is disconnectably connected to the outer cylinder; and a conductive and closing composite sleeve is provided on the inner wall of the outer cylinder at the lower injection groove of the upper water injection layer.

[0013] Furthermore, the conduction-closing composite sleeve includes a closing sleeve and a sliding sleeve;

[0014] Specifically, the closing sleeve wall is provided with an upper connecting groove and a lower connecting groove from top to bottom, and the closing sleeve is connected to the outer cylinder through a ball-throwing unlocking and sealing mechanism;

[0015] Specifically, the lower connecting groove corresponds to and is connected to the lower injection groove of the upper water injection layer;

[0016] Specifically, the lower sliding sleeve covers the lower connecting groove, the lower sliding sleeve is fixedly connected to the closing sleeve through the lower sliding sleeve pin, and the ball-throwing unlocking and sealing mechanism is arranged above the lower sliding sleeve;

[0017] Specifically, the outer cylinder is provided with an expanded diameter section below the lower injection groove of the upper water injection layer, and the expanded diameter section is provided with a liquid-passing support member;

[0018] Specifically, when the closing sleeve is seated on the liquid support member, the upper connecting groove is connected to the expanded diameter section, and the closing sleeve covers and seals the lower injection groove of the upper water injection layer;

[0019] Specifically, a stop is provided on the inner wall of the lower end of the closing sleeve, the inner diameter of the stop is smaller than the outer diameter of the lower sleeve, and the distance from the lower end of the lower sleeve to the stop is greater than or equal to the distance from the upper end of the lower sleeve to the lower end of the lower connecting groove.

[0020] Furthermore, the ball-throwing unlocking and sealing mechanism comprises a middle sliding sleeve and a locking block;

[0021] Specifically, the inner wall of the outer cylinder is provided with an outer locking groove, the wall of the closing sleeve is provided with a through locking path, the outer locking groove and the locking path correspond to and overlap with each other, and the locking block is located in the outer locking groove and the locking path to lock the closing sleeve and the outer cylinder;

[0022] Specifically, the middle sliding sleeve is provided with a release groove, the middle sliding sleeve is fixedly connected to the closing sleeve through a middle sliding sleeve pin, the middle sliding sleeve is located above the lower sliding sleeve, the release groove is located above the lock track, the radial dimension of the release groove is greater than or equal to the radial dimension of the outer lock groove, and the groove surface of the outer lock groove is a guide surface.

[0023] Furthermore, the upper sliding sleeve is fixedly connected to the outer cylinder via an upper sliding sleeve pin.

[0024] Furthermore, the inner diameter of the lower sliding sleeve is less than the inner diameter of the closing sleeve and is less than the inner diameter of the upper sliding sleeve.

[0025] Furthermore, the upper end of the outer cylinder is threadedly connected to an upper joint and sealed by a sealing ring, the liquid-passing support is a lower joint, the lower end of the outer cylinder is threadedly connected to the lower joint and sealed by a sealing ring;

[0026] Specifically, the inner wall of the lower joint is provided with a flow wall located in the expanded diameter section. The inner diameter of the flow wall of the lower joint is smaller than the outer diameter of the lower end of the closing sleeve. A liquid groove is provided on the flow wall. There is a flow annulus between the flow wall and the wall of the outer tube.

[0027] Furthermore, the groove surface of the outer locking groove on the outer cylinder is conical, and the end of the locking block close to the outer cylinder is conical, and the conical shape of the outer locking groove on the outer cylinder matches the conical shape of the locking block.

[0028] Furthermore, the axial dimension of the release groove is greater than the axial dimension of the locking block.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The utility model can realize two-layer high-pressure water injection wells and layered pressure-driven water injection wells with two different pressures or the need to rotate the water injection layer without the need to replace the water injection string, and realize two rounds of layer-changing water injection by dropping a ball at the wellhead.

[0031] 2. The utility model adjusts the size of the parts in the tool, and the cooperation between the parts realizes a three-level sliding sleeve structure; the utility model significantly improves the working efficiency of the tool and does not require ball dissolving operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a structural diagram of a double-round layer-changing high-pressure water injection device with a fixed pipe string according to the present invention;

[0033] Figure 2 It is a structural diagram of an enlarged structural diagram of the upper part of the utility model;

[0034] Figure 3 It is a schematic diagram of the enlarged structure of the lower part of the utility model.

[0035] In the figure: 1. upper joint; 2. outer cylinder; 2-1. upper injection groove of upper water injection layer; 2-2. lower injection groove of upper water injection layer; 2-3. diameter expansion section; 3. upper sealing ring of upper sleeve; 4. lower sealing ring of upper sleeve; 5. upper sleeve; 6. upper closing sealing ring; 7. lower closing sealing ring; 8. closing sleeve; 8-1. upper connecting groove; 8-2. lower connecting groove; 9. upper sealing ring of middle sleeve; 10. middle sleeve; 10-1. release groove; 10-2. stopper; 11. pin of middle sleeve; 12. locking block; 13. lower sealing ring of middle sleeve; 14. outer upper sealing ring; 15. upper sealing ring of lower sleeve; 16. lower sleeve; 17. lower sealing ring of lower sleeve; 18. outer lower sealing ring; 19. lower joint; 20. pin of upper sleeve; 21. pin of lower sleeve. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] Example 1:

[0038] See also Figures 1 to 3 The utility model provides a double-round layer-changing high-pressure water injection device for a fixed tubing string, comprising an outer tube 2, wherein the outer tube 2 is provided with an upper injection groove 2-1 for an upper water injection layer and a lower injection groove 2-2 for an upper water injection layer from top to bottom; an upper sliding sleeve 5 is provided on the inner wall of the outer tube 2 at the upper injection groove 2-1 of the upper water injection layer, and the upper sliding sleeve 5 covers the upper injection groove 2-1 of the upper water injection layer, and the upper sliding sleeve 5 is fixedly connected to the outer tube 2 by an upper sliding sleeve pin 20; a conductive and closed composite sleeve is provided on the inner wall of the outer tube 2 at the lower injection groove 2-2 of the upper water injection layer.

[0039] Furthermore, the conduction and closing composite sleeve includes a closing sleeve 8 and a lowering sleeve 16; the closing sleeve 8 is provided with an upper connecting groove 8-1 and a lower connecting groove 8-2 on its wall from top to bottom, the closing sleeve 8 is connected to the outer cylinder 2 by a ball-throwing unlocking and two-sealing mechanism, the lower connecting groove 8-2 corresponds to and is connected to the lower injection groove 2-2 of the upper water injection layer, the lowering sleeve 16 covers the lower connecting groove 8-2, the lowering sleeve 16 is fixedly connected to the closing sleeve 8 by a lowering sleeve pin 21, the ball-throwing unlocking and two-sealing mechanism is provided above the lowering sleeve 16; the outer cylinder 2 is in the upper water injection layer. An expansion section 2-3 is provided below the lower injection groove 2-2 of the layer, and the expansion section 2-3 is provided with a liquid-excess support member. When the closing sleeve 8 sits on the liquid-excess support member, the upper connecting groove 8-1 is connected with the expansion section 2-3, and the closing sleeve 8 covers and seals the lower injection groove 2-2 of the upper water injection layer; a stop 10-2 is provided on the inner wall of the lower end of the closing sleeve 8, and the inner diameter of the stop 10-2 is smaller than the outer diameter of the lower sleeve 16, and the distance from the lower end of the lower sleeve 16 to the stop 10-2 is greater than or equal to the distance from the upper end of the lower sleeve 16 to the lower end of the lower connecting groove 8-2.

[0040] Among them, the diameter expansion section 2-3 is used to open the water injection channel of the lower water injection layer.

[0041] Among them, the baffle 10-2 is used to cooperate with the lower sleeve 16 to complete the primary sealing of the lower water injection layer.

[0042] Furthermore, the ball-throwing unlocking and sealing mechanism includes a middle sliding sleeve 10 and a locking block 12. The inner wall of the outer tube 2 is provided with an outer locking groove, and the sleeve wall of the closing sleeve 8 is provided with a through locking path. The outer locking groove corresponds to and coincides with the locking path. The locking block 12 is located in the outer locking groove and the locking path to lock the closing sleeve 8 with the outer tube 2. The middle sliding sleeve 10 is provided with a release groove 10-1. The middle sliding sleeve 10 is fixedly connected to the closing sleeve 8 through a middle sliding sleeve pin 11. The middle sliding sleeve 10 is located above the lower sleeve 16. The release groove 10-1 is located above the locking path. The radial dimension of the release groove 10-1 is greater than or equal to the radial dimension of the outer locking groove. The groove surface of the outer locking groove is a guide surface. When the release groove 10-1 coincides with the locking path, the locking block 12 moves outward under the guidance of the guide surface and under the action of gravity, so that the closing sleeve 8 is disconnected from the outer tube 2.

[0043] Specifically, the inner diameter of the lower sliding sleeve 16 is less than the inner diameter of the closing sleeve 8 and is less than the inner diameter of the upper sliding sleeve 5 .

[0044] Furthermore, the upper end of the outer tube 2 is threadedly connected to the upper joint 1 and sealed by a sealing ring. The liquid support is a lower joint 19. The lower end of the outer tube 2 is threadedly connected to the lower joint 19 and sealed by a sealing ring. The inner wall of the lower joint 19 is provided with a flow wall located in the expanded diameter section 2-3. The inner diameter of the flow wall of the lower joint 19 is smaller than the outer diameter of the lower end of the closing sleeve 8. A liquid groove 19-1 is provided on the flow wall. There is a flow annulus between the flow wall and the wall of the outer tube 2. The liquid groove 19-1 and the flow annulus serve to connect the flow channel to realize the second round of injection of the lower water injection layer.

[0045] Specifically, an upper sleeve upper sealing ring 3 is provided on the outer wall of the upper sleeve 5 above the upper injection groove 2-1 of the upper water injection layer, and an upper sleeve lower sealing ring 4 is provided on the outer wall of the upper sleeve 5 below the upper injection groove 2-1 of the upper water injection layer. The upper sleeve pin 20 is located between the upper sleeve upper sealing ring 3 and the lower sleeve upper sealing ring 4.

[0046] Specifically, an upper closing sealing ring 6 and a lower closing sealing ring 7 are provided on the outer wall of the closing sleeve 8 above the upper connecting groove 8-1, and the distance between the upper closing sealing ring 6 and the lower closing sealing ring 7 is greater than the lower injection groove 2-2 of the upper water injection layer.

[0047] Specifically, an outer upper sealing ring 14 is provided on the outer wall of the closing sleeve 8 between the lower connecting groove 8 - 2 and the upper connecting groove 8 - 1 , an outer lower sealing ring 18 is provided on the outer wall of the closing sleeve 8 below the lower connecting groove 8 - 2 , and the locking block is located above the outer upper sealing ring 14 .

[0048] Specifically, the outer wall of the lower sleeve 16 is provided with a lower sleeve upper sealing ring 15 above the lower connecting groove 8-2, and the outer wall of the lower sleeve 16 is provided with a lower sleeve lower sealing ring 17 below the lower connecting groove 8-2, and the lower sleeve pin 21 is located between the lower sleeve upper sealing ring 15 and the lower sleeve lower sealing ring 17.

[0049] Specifically, the outer wall of the middle sleeve 10 is provided with a middle sleeve upper sealing ring 9 and a middle sleeve lower sealing ring 13 , and the release groove 10 - 1 and the middle sleeve pin 11 are located between the middle sleeve upper sealing ring 9 and the middle sleeve lower sealing ring 13 .

[0050] Specifically, the upper sealing ring 3 of the upper sliding sleeve and the upper sealing ring 4 of the lower sliding sleeve are installed in the sealing groove on the outer wall of the upper sliding sleeve 5; the upper closing sealing ring 6, the lower closing sealing ring 7, the outer upper sealing ring 14, and the outer lower sealing ring 18 are installed in the sealing groove on the outer wall of the closing sleeve 8; the upper sealing ring 15 of the lower sliding sleeve and the lower sealing ring 17 of the lower sliding sleeve are installed in the sealing groove on the outer wall of the lower sleeve 16; the upper sealing ring 9 of the middle sliding sleeve and the lower sealing ring 13 of the middle sliding sleeve are installed in the sealing groove on the outer wall of the middle sliding sleeve 10.

[0051] Preferably, the groove surface of the outer locking groove on the outer cylinder 2 is conical, and the end of the locking block 12 close to the outer cylinder 2 is conical, and the conical shape of the outer locking groove on the outer cylinder 2 matches the conical shape of the locking block 12.

[0052] Preferably, the axial dimension of the release groove 10 - 1 is larger than the axial dimension of the locking block 12 , so as to facilitate the locking block 12 to enter the release groove 10 - 1 .

[0053] Preferably, the inner diameter of the lower sleeve 16 is smaller than the inner diameter of the middle sleeve 10, and the inner diameter difference is 3-6 mm, so that a valve ball with a diameter larger than the inner diameter of the lower sleeve 16 can pass through the upper sleeve 5 and the middle sleeve 10, and the inner diameter of the middle sleeve 10 is smaller than the inner diameter of the upper sleeve 5, and the inner diameter difference is 3-6 mm, so that a valve ball with a diameter larger than the inner diameter of the middle sleeve 10 can pass through the upper sleeve 5.

[0054] Preferably, a mounting hole needs to be opened on the outer cylinder 2 to install the middle sliding sleeve pin 11, and the mounting hole is sealed after the middle sliding sleeve pin 11 is installed.

[0055] Example 2:

[0056] Based on Example 1, this example provides a method for using a dual-round layer-changing high-pressure water injection device with a fixed string, including the following steps:

[0057] S1. The utility model is used in a water injection well that needs to inject water into two injection layers in two rounds. The utility model is lowered into the water injection well along with the water injection string and installed on the packer between the two layers. After the packer is set, the upper injection layer is sealed, and the lower injection layer can be injected at this time.

[0058] S2. When it is necessary to close the lower water injection layer and inject the upper water injection layer, a valve ball with a diameter larger than the inner diameter of the lower sleeve 16 and smaller than the inner diameter of the middle sleeve 10 is put in. The valve ball sits on the upper end of the lower sleeve 16 to close the lower sleeve 16. After pressure is applied and the lower sleeve pin 21 is cut off, the lower sleeve 16 moves downward to the stop 10-2 and is limited. The lower connecting groove 8-2 is opened, the lower water injection layer is closed, and water can be injected into the upper water injection layer only.

[0059] S3. When the lower water injection layer needs to be injected again to close the upper water injection layer, a valve ball with a diameter larger than the inner diameter of the middle sleeve 10 and smaller than the inner diameter of the upper sleeve 5 is injected. The injected valve ball sits on the upper end of the middle sleeve 10 to close the middle sleeve 10. Pressure is applied to break the middle sleeve pin 11, and the middle sleeve 10 moves downward. The release groove 10-1 is aligned with the locking block 12, and the locking block 12 can be separated from the outer cylinder 2, so that the closing sleeve 8 moves downward to the lower sleeve 16. The upper connecting groove 8-1 is connected to the expanded diameter section 2-3, and the upper closing sealing ring 6 is located above the lower injection groove 8-2 of the upper water injection layer, and the lower closing sealing ring 7 is located below the lower injection groove 8-2 of the upper water injection layer. The upper water injection layer is closed and the lower water injection layer is opened, so that only the lower water injection layer can be injected without injecting the upper water injection layer.

[0060] S4. When it is necessary to inject water into the upper water injection layer to close the lower water injection layer, a valve ball with a diameter larger than the inner diameter of the upper sliding sleeve 5 is inserted. The inserted valve ball sits on the upper port of the upper sliding sleeve 5 to close the upper sliding sleeve 5. Pressure is applied to break the upper sliding sleeve pin 20, and the upper sliding sleeve 5 moves downward. The upper injection groove 2-1 of the upper water injection layer is opened, and the lower water injection layer is closed. Then, it is possible to inject water into the upper water injection layer only.

[0061] All components not discussed in detail in this application and the connection methods of the components in this application are well-known technologies in the technical field and can be directly applied without further explanation.

[0062] In this utility model, the term "plurality" refers to two or more, unless otherwise specified. Terms such as "installed," "connected," "connected," and "fixed" should be interpreted broadly. For example, "connected" can mean fixed, removable, or integral; "connected" can mean directly or indirectly through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this utility model based on specific circumstances.

[0063] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as "up", "down", "left", "right", "front" and "back" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0064] Throughout this specification, terms such as "one embodiment," "some embodiments," and "specific embodiments" mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A high-pressure water injection device with double-round layer change and fixed pipe string, comprising an outer cylinder, wherein the outer cylinder is provided with an upper injection groove of the upper water injection layer and a lower injection groove of the upper water injection layer from top to bottom; It is characterized by: An upper sliding sleeve is provided on the inner wall of the outer cylinder at the upper injection groove of the upper water injection layer, and the upper sliding sleeve covers the upper injection groove of the upper water injection layer. The upper sliding sleeve is disconnectably connected to the outer cylinder; A conducting and closing composite sleeve is provided on the inner wall of the outer cylinder at the lower injection groove of the upper water injection layer.

2. The device for high-pressure water injection with double-round layer change of fixed pipe string according to claim 1 is characterized in that: The conduction and closing composite sleeve includes a closing sleeve and a sliding sleeve; The closing sleeve wall is provided with an upper connecting groove and a lower connecting groove from top to bottom, and the closing sleeve is connected to the outer cylinder through a ball-throwing unlocking and sealing mechanism; The lower connecting groove corresponds to and is connected to the lower injection groove of the upper water injection layer; The lower sliding sleeve covers the lower connecting groove, and the lower sliding sleeve is fixedly connected to the closing sleeve through the lower sliding sleeve pin, and the ball-throwing unlocking and sealing mechanism is arranged above the lower sliding sleeve; The outer cylinder is provided with an expanded diameter section below the lower injection groove of the upper water injection layer, and the expanded diameter section is provided with a liquid-excess support member; When the closing sleeve is seated on the liquid support member, the upper connecting groove is connected to the expanded diameter section, and the closing sleeve covers and seals the lower injection groove of the upper water injection layer; The inner wall of the lower end of the closing sleeve is provided with a stop, the inner diameter of the stop is smaller than the outer diameter of the lower sleeve, and the distance from the lower end of the lower sleeve to the stop is greater than or equal to the distance from the upper end of the lower sleeve to the lower end of the lower connecting groove.

3. The device for high-pressure water injection with double-round layer change of fixed pipe string according to claim 2, characterized in that: The ball-throwing unlocking and sealing mechanism comprises a middle sliding sleeve and a locking block; The inner wall of the outer cylinder is provided with an outer locking groove, and the wall of the closing sleeve is provided with a through locking path. The outer locking groove corresponds to and overlaps with the locking path. The locking block is located in the outer locking groove and the locking path to lock the closing sleeve and the outer cylinder. The middle sliding sleeve is provided with a release groove, and the middle sliding sleeve is fixedly connected to the closing sleeve through a middle sliding sleeve pin. The middle sliding sleeve is located above the lower sliding sleeve, and the release groove is located above the lock track. The radial dimension of the release groove is greater than or equal to the radial dimension of the outer lock groove, and the groove surface of the outer lock groove is a guide surface.

4. The device for high-pressure water injection with double-round layer change of fixed pipe string according to claim 3 is characterized in that: The upper sliding sleeve is fixedly connected to the outer cylinder via an upper sliding sleeve pin.

5. The device for high-pressure water injection with double-round layer change of fixed pipe string according to claim 4 is characterized in that: The inner diameter of the lower sleeve is less than the inner diameter of the closing sleeve and is less than the inner diameter of the upper sleeve.

6. The device for high-pressure water injection with double-round layer change of fixed pipe string according to claim 5, characterized in that: The upper end of the outer cylinder is threadedly connected to an upper joint and sealed by a sealing ring. The liquid-passing support is a lower joint. The lower end of the outer cylinder is threadedly connected to the lower joint and sealed by a sealing ring. The inner wall of the lower joint is provided with a flow wall located in the expanded diameter section. The inner diameter of the flow wall of the lower joint is smaller than the outer diameter of the lower end of the closing sleeve. A liquid groove is provided on the flow wall. There is a flow annulus between the flow wall and the wall of the outer cylinder.

7. The device for high-pressure water injection with double-round layer change of fixed pipe string according to claim 3 is characterized in that: The groove surface of the outer locking groove on the outer cylinder is conical, and the end of the locking block close to the outer cylinder is conical. The conical shape of the outer locking groove on the outer cylinder matches the conical shape of the locking block.

8. The device for high-pressure water injection with double-round layer change of fixed pipe string according to claim 3 is characterized in that: The axial dimension of the release groove is greater than the axial dimension of the locking block.

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