Segmented filling well completion device

Abstract

The subsection filling well completion device comprises an outer filling server and an inner filling server, a center pipe is arranged in the outer filling server, center pipe filling openings are formed in the outer filling server, a first sealing assembly capable of moving between a first position and a second position is arranged in the center pipe in the axial direction, and at the first position, the two filling openings completely coincide, and at the second position, the two filling openings completely coincide; at the second position, the two filling openings are completely staggered, a second sealing assembly is connected outside the pipe wall of the central pipe, and in the non-pressurized state, the second sealing assembly blocks the filling opening of the central pipe and opens the filling opening of the central pipe in the pressurized state; the inner filling server comprises an inner filling cylinder and an elastic positioning cylinder, when the inner filling server is filled into the outer filling server, a plurality of elastic positioning keys are clamped with a plurality of positioning grooves one by one, and an inner filling opening is overlapped with the central pipe filling opening and the sliding sleeve filling opening. According to the device, segmented gravel packing is achieved, backflow of gravel after gravel packing is effectively prevented, the inner drift diameter is not reduced, and later-period in-pipe action construction is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas development, and in particular to a segmented filling completion device. Background Art

[0002] As one of the most advanced sand control methods, horizontal well open hole gravel packing technology is the leading process technology for horizontal well completion in loose sandstone reservoirs. During the gravel packing process, horizontal wells with long horizontal sections are prone to sedimentation and sand bridge blockage, thus prematurely interrupting the gravel packing process, resulting in low gravel packing rate, poor sand control effect and short sand control life.

[0003] The utility model patent "A Gravel Packing Device for Horizontal Wells to Prevent Backflow" (authorized patent number ZL2014208647689) published on June 10, 2015, mainly consists of an upper joint, an upper closing assembly, a lower closing assembly, a buckle joint, a switch sleeve, and a sealing cannula with a filling port on the guide head. In view of the problem of gravel filling in multi-oil layer well sections and long horizontal well sections, the current solution is to use a one-stage gravel packing device. The tool has the following main shortcomings: First, the sealing effect of this type of filling device is poor, and the filling port cannot be fully closed or is not closed tightly after gravel filling, resulting in gravel spitting back. Second, this type of filling device is difficult to locate, which is easy to cause unsuccessful positioning during on-site construction, affecting the construction progress. Third, this type of filling device has a pipe string shrinkage, and the inner diameter of the lower end of the pipe string is getting smaller and smaller, which affects the later pipe string re-entry operation construction.

[0004] Therefore, there is a need in the prior art for improving the packing completion device. Summary of the invention

[0005] In view of this, the purpose of an embodiment of the present invention is to propose a segmented filling completion device. The device of the present invention can realize segmented gravel filling, implement refined filling, mining, and implement segmented gravel filling construction needs, effectively prevent gravel backflow after gravel filling, and the internal diameter of the segmented gravel filling does not shrink, which is conducive to the later in-pipe action construction.

[0006] Based on the above purpose, the embodiment of the present invention provides a segmented filling completion device, including an outer filling server and an inner filling server which can be connected to each other, wherein:

[0007] A central tube is arranged in the external filling server, a central tube filling port is provided on the central tube, a first sealing component is arranged axially in the central tube, the first sealing component is located above the plane where the central tube filling port is located, and comprises elastic petal claws and a positioning sleeve connected in sequence, a sleeve filling port is provided on the positioning sleeve, a plurality of positioning grooves are provided on the surface of the positioning sleeve, the first sealing component is movable between a first position and a second position, at the first position, the sleeve filling port coincides with the central tube filling port, at the second position, the sleeve filling port is staggered with the central tube filling port, a second sealing component is connected to the outside of the central tube wall, in a non-pressurized state, the second sealing component blocks the central tube filling port, and in a pressurized state, the second sealing component opens the central tube filling port;

[0008] The inner filling server includes an inner filling tube and an elastic positioning tube which are arranged along the axial direction and connected in sequence. The inner filling tube is provided with an inner filling port, and the surface of the elastic positioning tube has a plurality of elastic positioning keys. When the inner filling server is filled into the outer filling server, the plurality of elastic positioning keys are engaged with the plurality of positioning grooves one by one, and the inner filling port coincides with the filling port of the center tube and the filling port of the sliding sleeve.

[0009] In some embodiments, the inner filling server also includes a limit assembly, which is fixed on the radial inner side of the elastic positioning cylinder. When the inner filling server is filled into the outer filling server, under the pressurized state, the limit assembly presses the elastic positioning key and multiple positioning grooves to limit the movement of the elastic positioning cylinder.

[0010] In some embodiments, the limit assembly includes a limit piston, a stop block, and a piston return spring. One end of the stop block is rotatably fixed on the radial inner side of the elastic positioning key. One end of the piston return spring abuts against the limit piston, and the other end abuts against the inner wall of the inner filling server. In the pressurized state, the limit piston compresses the piston return spring axially and drives the stop block to be pressed toward the elastic positioning key. In the non-pressurized state, the piston return spring pushes the limit piston to reset and drives the stop block to reset.

[0011] In some embodiments, the second sealing assembly includes a switch sleeve and a sleeve return spring that are axially connected and movable along the axial direction. A switch sleeve shear pin is provided at the end of the switch sleeve. In a non-pressurized state, the switch sleeve shear pin is aligned with the center tube filling port and blocks the center tube filling port. In a pressurized state, the switch sleeve shear pin is disconnected and causes the switch sleeve to move downward, compressing the sleeve return spring to expose the center tube filling port.

[0012] In some embodiments, an outer layer of the second sealing component is provided with an outer protective cover, and the outer protective cover is threadedly connected to the central pipe.

[0013] In some embodiments, the external filling server also includes an upper joint, a lifting short section, and a lower joint. The upper joint, the lifting short section, the center tube, and the lower joint are fixedly connected in sequence along the axial direction, and the axial movable range of the first sealing assembly is limited between the upper joint and the lower joint.

[0014] In some embodiments, a guide key is provided on the lifting nipple, and the radial inner side of the guide key is connected to the positioning sleeve to limit the circumferential rotation of the first sealing assembly.

[0015] In some embodiments, the surface of the elastic split claw has a protrusion, and a limiting groove is further provided at the upper end of the lifting short section. When the first sealing assembly is in the second position, the protrusion is embedded in the limiting groove.

[0016] In some embodiments, the upper joint, the lifting nipple, the central pipe and the lower joint are fixedly connected by threaded engagement.

[0017] In some embodiments, there are two positioning grooves and two elastic positioning keys, the two positioning grooves are axially spaced apart on the positioning sleeve, and the two elastic positioning keys are axially spaced apart on the elastic positioning cylinder. When the inner filling server is filled into the outer filling server, the elastic positioning keys engage with the positioning grooves.

[0018] The present invention has at least the following beneficial technical effects:

[0019] (1) An external filling server and an internal filling server are set up to coordinate filling. Multiple external filling servers are arranged in sections in the area to be filled, and one internal filling server completes the filling in sections to improve the efficiency of gravel filling in the long horizontal well section of the oil and gas well;

[0020] (2) Multiple sealing components are set to automatically seal in the non-filling state. When the inner filling server is filled into the outer filling server, and when filling gravel, the hole position is automatically aligned and automatically sealed according to the pressure state and structural coordination. After the gravel is filled, the filling port is fully closed in time to effectively prevent the gravel spitting phenomenon, and the device has a double sealing effect;

[0021] (3) Multiple positioning components are provided to enable the internal filling server to quickly locate itself during the segmented filling process and prevent it from shifting during the filling process. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying creative work.

[0023] Figure 1A schematic diagram of an embodiment of an external filling server of a segmented filling device provided by the present invention;

[0024] Figure 2 A schematic diagram of an embodiment of an inner filling server of a segmented filling device provided by the present invention;

[0025] Figure 3 This is a schematic diagram of the segmented filling device provided by the present invention in the filling state.

[0026] Description of reference numerals:

[0027] 1. Upper joint; 2. Limiting groove; 3. Lifting short section; 4. Elastic split claw; 5. Guide key; 6. Guide groove; 7. Switch sleeve shear nail; 8. Center tube filling port; 9. Positioning sleeve filling port; 10. Switch sleeve; 11. Center tube; 12. Reset spring; 13. Outer protective cover; 14. Positioning sleeve; 15. Lower joint; 16. Positioning groove; 17. Oil pipe short section; 18. Inner filling cylinder; 19. Inner filling port; 20. Elastic positioning cylinder; 21. Elastic positioning key; 22. Piston retaining ring; 23. Limiting piston; 24. Block bolt; 25. Block; 26. Piston reset spring; 27. Block rod; 28. Shift joint; 29. ​​Guide head; 30. "O" shaped rubber ring. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field of the present invention; the terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For example, the directions or positions indicated by the terms "length", "width", "up", "down", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the directions or positions shown in the drawings, which are only for the convenience of description and should not be understood as limitations on the present technical solution.

[0030] The terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions; the terms "first", "second", etc. in the specification and claims of the present invention or the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order. "Multiple" means two or more, unless otherwise clearly and specifically defined.

[0031] In the specification and claims of the present invention and the above-mentioned drawings, when an element is referred to as being "fixed to" or "mounted on" or "disposed on" or "connected to" another element, it may be directly or indirectly located on the other element. For example, when an element is referred to as being "connected to" another element, it may be directly or indirectly connected to the other element.

[0032] In addition, reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0033] The present invention provides a segmented filling completion device, comprising an outer filling server and an inner filling server which can be connected to each other, such as Figure 1 FIG. 1 is a schematic diagram of an embodiment of an external filling server of a segmented filling device provided by the present invention. Figure 2 FIG. 1 is a schematic diagram of an embodiment of an inner filling server. Figure 3 The diagram is shown in the filling state, including:

[0034] A central tube 11 is arranged in the external filling server, a central tube filling port 8 is provided on the central tube 11, a first sealing component is arranged axially in the central tube 11, the first sealing component is located above the plane where the central tube filling port 8 is located, and comprises an elastic petal claw 4 and a positioning sleeve 14 connected in sequence, a sleeve filling port 9 is provided on the positioning sleeve 14, a plurality of positioning grooves 16 are provided on the surface of the positioning sleeve 14, the first sealing component 4, 14 is movable between a first position and a second position, at the first position, the sleeve filling port 9 coincides with the central tube filling port 8, at the second position, the sleeve filling port 9 is staggered with the central tube filling port 8, a second sealing component is connected to the outside of the central tube 11 wall, in a non-pressurized state, the second sealing component blocks the central tube filling port 8, and in a pressurized state, the second sealing component opens the central tube filling port 8;

[0035] The inner filling server includes an inner filling cylinder 18 and an elastic positioning cylinder 20 which are arranged along the axial direction and connected in sequence. The inner filling cylinder 18 is provided with an inner filling port 19. The surface of the elastic positioning cylinder 20 has a plurality of elastic positioning keys 21. When the inner filling server is filled into the outer filling server, the plurality of elastic positioning keys 21 are engaged one by one with the plurality of positioning grooves 16, and the inner filling port 19 coincides with the center tube filling port 8 and the sleeve filling port 9.

[0036] Further, the inner filling server also includes a limit assembly, which is fixed on the radial inner side of the elastic positioning cylinder 20. When the inner filling server is filled into the outer filling server, the limit assembly presses the elastic positioning key 21 and the plurality of positioning grooves 16 in the pressurized state to limit the movement of the elastic positioning cylinder 20. In some embodiments, the limit assembly includes a limit piston 23, a stopper 25, and a piston return spring 26. One end of the stopper 25 is rotatably fixed on the radial inner side of the elastic positioning key 21. One end of the piston return spring 26 abuts against the limit piston 23, and the other end abuts against the inner wall of the inner filling server. In the pressurized state, the limit piston 23 axially compresses the piston return spring 26 and drives the stopper 25 to press against the elastic positioning key 21. In the non-pressurized state, the piston return spring 26 pushes the limit piston 23 to reset and drives the stopper 25 to reset. Further, the second sealing assembly 10, 12 comprises a switch sleeve 10 and a sleeve return spring 12 connected in the axial direction and movable in the axial direction, and a switch sleeve shear pin 7 is provided at the end of the switch sleeve 10. In the non-pressurized state, the switch sleeve shear pin 7 is aligned with the central tube filling port 8 and blocks the central tube filling port 8. In the pressurized state, the switch sleeve shear pin 7 is disconnected and the switch sleeve 10 compresses the sleeve return spring 12 to expose the central tube filling port 8. In some embodiments, the outer layer of the second sealing assembly is provided with an outer protective cover 13, and the outer protective cover 13 is threadedly connected to the central tube 11.

[0037] Furthermore, there are two positioning grooves 16 and two elastic positioning keys 21. The two positioning grooves 16 are axially spaced apart in the positioning sleeve 14, and the two elastic positioning keys 21 are axially spaced apart in the elastic positioning tube 20. When the inner filling server is filled into the outer filling server, the elastic positioning keys 21 engage with the positioning grooves 16.

[0038] Furthermore, the external filling server also includes an upper joint 1, a lifting short section 3, and a lower joint 15. The upper joint 1, the lifting short section 3, the central tube 11, and the lower joint 15 are fixedly connected in sequence along the axial direction, and the axial movable range of the first sealing assembly is limited between the upper joint 1 and the lower joint 15. In some embodiments, a guide key 5 is provided on the lifting short section 3, and the radial inner side of the guide key 5 is connected to the positioning sleeve 14 to limit the circumferential rotation of the first sealing assembly. The surface of the elastic split claw 4 has a protrusion, and a limiting groove 2 is further provided at the upper end of the lifting short section 3. When the first sealing assembly is in the second position, the protrusion is embedded in the limiting groove 2.

[0039] The present invention is further explained below by a specific embodiment, and the specific drawings are referred to Figures 1 to 3 .

[0040] External filling server part: upper joint 1, lifting short section 3, central tube 11, lower joint 15 are connected together by threads in sequence, elastic split claw 4 and positioning sleeve 14 are connected by threads, elastic split claw 4 and positioning sleeve 14 are arranged in the central tube 11 as a whole and can move axially on the inner wall of the central tube 11, and the upper and lower ends of the elastic split claw 4 and positioning sleeve 14 as a whole can move to the root of the upper joint 1 and the lower joint 15 respectively. The guide key 5 is threadedly installed at the lower end of the lifting short section 3. Figure 1 The lower end is the right end of the lifting short section 3, and the upper end of the guide key 5 is fixed in the guide groove 6 of the positioning sleeve 14 and has a gap with the guide groove 6, ensuring that the elastic petal claw 4 and the positioning sleeve 14 only move axially without radial rotation, thereby ensuring that the center tube filling port 8 and the positioning sleeve filling port 9 are highly overlapped after the positioning sleeve 14 descends into place.

[0041] The upper end of the elastic petal claw 4 has an external protruding part, which is not shown in the figure. When the internal filling server moves upward, it drives the elastic petal claw 4 and the positioning sleeve 14 to move upward as a whole at the same time. Due to the limiting effect of the lower guide key 5 and the guide groove 6, the elastic petal claw 4 and the positioning sleeve 14 will not continue to move upward during the process but will shift axially. At this time, the filling port 8 of the central tube and the filling port 9 of the positioning sleeve are staggered. After moving upward to the limiting position, the external protruding part of the elastic petal claw 4 opens and is embedded in the limiting groove 2 at the upper end of the lifting short section 3, ensuring that the elastic petal claw 4 and the positioning sleeve 14 are fixed in this position after the filling is completed, thereby realizing that the filling port 8 of the central tube is sealed by the positioning sleeve 14.

[0042] The switch sleeve 10, the sleeve return spring 12 and the outer protective cover 13 are installed on the outer wall of the central tube 11. The outer protective cover 13 and the central tube 11 are threadedly connected. The outer protective cover 13 protects the switch sleeve 10 and the sleeve return spring 12 outside the switch sleeve 10 and the sleeve return spring 12. The switch sleeve 10 can slide axially between the outer protective cover 13 and the central tube 11. After the gravel filling starts, the switch sleeve shear pins 7 on the switch sleeve 10 can be cut off under the action of liquid pressure, so that the switch sleeve 10 moves downward and compresses the sleeve return spring 12. After the gravel filling is completed, the switch sleeve 10 moves upward under the elastic force of the sleeve return spring 12, thereby sealing the central tube filling port 8 of the central tube 11, thereby realizing the double sealing function of the central tube filling port 8 on the central tube 11 of the filling device.

[0043] Internal filling server part: the tubing nipple 17, the internal filling tube 18, the elastic positioning tube 20, the gear joint 28 and the guide head 29 are connected by threads. The internal filling port 19 is opened on the internal filling tube 18. After the elastic positioning tube 20 is successfully positioned, the three holes of the internal filling port 19, the center tube filling port 8 and the positioning sleeve filling port 9 are overlapped, and gravel filling can be carried out. There are two raised elastic positioning keys 21 on the elastic positioning tube 20, which are just engaged with the two positioning grooves 16 on the positioning sleeve 14 in the filling state, ensuring the accurate positioning of the tool and ensuring that the internal filling server will not shift axially. In addition, the present invention further provides a piston limiting structure, wherein a piston retaining ring 22 is threadedly connected in the inner filling cylinder 18, and below is a limiting piston 23 that can freely move axially along the inner filling cylinder 18, and a piston return spring 26 is sleeved outside the retaining rod 27 and there is a gap between the retaining rod 27, and the piston return spring 26 is in a slightly compressed state, with the upper end abutting against the limiting piston 23 and the lower end abutting against the guide head 29. The block bolt 24 connects one end of the block 25 to the opening of the side wall of the inner filling tube 18, and the block 25 can rotate around the block bolt 24. The function of the piston limiting structure is that when filling, the pressure in the tube increases, and the pressure impacts the limit piston 23 to move downward, further squeezing the inner side of the block 25 to make the block 25 rotate outward, pressing the elastic positioning key 21 and the positioning groove 16 to prevent the elastic positioning key 21 from shrinking inward, and further positioning the inner filling server to prevent it from moving axially. When the filling stops and the pressure is released, the elastic force of the piston reset spring 26 resets the limit piston 23, and the block 25 automatically returns to its original position.

[0044] The operation process of the staged well completion device of the present invention is as follows:

[0045] During the gravel filling construction process, the inner filling server is inserted into the outer filling server. When the two raised elastic positioning keys 21 on the elastic positioning cylinder 20 reach the two positioning grooves 16 of the positioning sleeve 14, the elastic positioning keys 21 open and embed into the positioning grooves 16. The inner filling server pushes the elastic petal claws 4 and the positioning sleeve 14 connected together by threads to move downward and are blocked by the lower joint 15. At this time, the central tube filling port 8 and the positioning sleeve filling port 9 coincide with each other, and the wellhead pump fluid is pressurized. After reaching a certain pressure, the switch sleeve shear pin 7 is cut off, and the switch sleeve 10 moves downward to compress the reset spring 12, exposing the central tube filling port 8, so that the tool is connected inside and outside to implement gravel filling operations. After the gravel filling construction is completed, the wellhead is no longer pumped for pressurization. The switch sleeve 10 moves upward under the elastic force of the reset spring 12, closing the central tube filling port 8 and connecting it to the outside. At the same time, the inner filling server is lifted up, driving the elastic split claw 4 and the positioning sleeve 14 connected together by threads to move upward. When the elastic split claw 4 moves up to the position of the limit groove 2, the elastic split claw 4 opens and embeds into the groove, so that the central tube filling port 8 and the positioning sleeve filling port 9 are staggered, ensuring the sealing of the central tube filling port 8 again, playing a double sealing role. Continue to lift the inner filling server and the outer filling server. The gravel filling construction of this section is completed, and repeat the above steps to another section to complete the gravel filling operation of another section.

[0046] The present invention provides a segmented filling completion device. During the filling process, multiple external filling servers can be set underground for multi-segment connection, and the internal filling servers can fill the segments one by one, thereby improving the gravel filling efficiency of long horizontal well sections, implementing refined filling, mining, and implementing segmented gravel filling construction needs, and effectively preventing gravel backflow after gravel filling. In addition, in the segmented gravel filling, the internal diameter does not shrink, which is conducive to the later in-pipe action construction.

[0047] The above are exemplary embodiments disclosed in the present invention, but it should be noted that various changes and modifications may be made without departing from the scope disclosed in the embodiments of the present invention as defined in the claims. The functions, steps and / or actions of the method claims according to the disclosed embodiments described herein do not need to be performed in any particular order. In addition, although the elements disclosed in the embodiments of the present invention may be described or required in individual form, they may also be understood as multiple unless explicitly limited to the singular.

[0048] It should be understood that, as used herein, the singular forms "a", "an" are intended to include the plural forms as well, unless the context clearly supports an exception. It should also be understood that, as used herein, "and / or" refers to any and all possible combinations including one or more of the associated listed items.

[0049] The serial numbers of the embodiments disclosed in the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0050] A person skilled in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the disclosure of the embodiments of the present invention, including the claims, is limited to these examples; under the idea of ​​the embodiments of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the embodiments of the present invention as above, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the embodiments of the present invention.

Claims

1. A staged filling completion device, characterized in that: It includes an external filling server and an internal filling server which can be connected to each other, wherein: The external filling server is provided with a central tube (11), a central tube filling port (8) is provided on the central tube (11), a first sealing component is axially provided in the central tube (11), the first sealing component is located above the plane where the central tube filling port (8) is located, and comprises elastic petal claws (4) and a positioning sleeve (14) connected in sequence, a sleeve filling port (9) is provided on the positioning sleeve (14), a plurality of positioning grooves (16) are provided on the surface of the positioning sleeve (14), the first sealing component is movable between a first position and a second position, in the first position, the sleeve filling port (9) coincides with the central tube filling port (8), in the second position, the sleeve filling port (9) is offset from the central tube filling port (8), a second sealing component is connected to the outside of the central tube (11) wall, in a non-pressurized state, the second sealing component blocks the central tube filling port (8), and in a pressurized state, the second sealing component opens the central tube filling port (8); The inner filling server comprises an inner filling tube (18) and an elastic positioning tube (20) which are arranged along the axial direction and connected in sequence. The inner filling tube (18) is provided with an inner filling port (19). The surface of the elastic positioning tube (20) has a plurality of elastic positioning keys (21). When the inner filling server is filled into the outer filling server, the plurality of elastic positioning keys (21) engage with the plurality of positioning grooves (16) one by one, and the inner filling port (19) coincides with the central tube filling port (8) and the sleeve filling port (9).

2. The staged filling completion device according to claim 1, characterized in that: The inner filling server also includes a limit assembly, which is fixed on the radial inner side of the elastic positioning cylinder (20). When the inner filling server is filled into the outer filling server, under the pressurized state, the limit assembly presses the elastic positioning key (21) and the plurality of positioning grooves (16) to limit the movement of the elastic positioning cylinder (20).

3. The staged filling completion device according to claim 2, characterized in that: The limit assembly comprises a limit piston (23), a stopper (25), and a piston return spring (26); one end of the stopper (25) is rotatably fixed on the radial inner side of the elastic positioning key (21); one end of the piston return spring (26) abuts against the limit piston (23), and the other end abuts against the inner wall of the inner filling server; in a pressurized state, the limit piston (23) compresses the piston return spring (26) axially and drives the stopper (25) to be pressed toward the elastic positioning key (21); in a non-pressurized state, the piston return spring (26) pushes the limit piston (23) to be reset and drives the stopper (25) to be reset.

4. The staged filling completion device according to claim 1, characterized in that: The second sealing component comprises a switch sleeve (10) and a sleeve return spring (12) which are axially connected and movable in the axial direction. A switch sleeve shear pin (7) is provided at the end of the switch sleeve (10). In a non-pressurized state, the switch sleeve shear pin (7) is aligned with the center tube filling port (8) and blocks the center tube filling port (8). In a pressurized state, the switch sleeve shear pin (7) is disconnected and causes the switch sleeve (10) to compress the sleeve return spring (12) to expose the center tube filling port (8).

5. The staged filling completion device according to claim 4, characterized in that: The outer layer of the second sealing component is provided with an outer protective cover (13), and the outer protective cover (13) is threadedly connected to the central pipe (11).

6. The staged filling completion device according to claim 1, characterized in that: The external filling server also includes an upper joint (1), a lifting short joint (3), and a lower joint (15); the upper joint (1), the lifting short joint (3), the central tube (11), and the lower joint (15) are fixedly connected in sequence along the axial direction; and the axial movable range of the first sealing component is limited between the upper joint (1) and the lower joint (15).

7. The staged filling completion device according to claim 6, characterized in that: The lifting nipple (3) is provided with a guide key (5), and the radial inner side of the guide key (5) is connected to the positioning sleeve (14) to limit the circumferential rotation of the first sealing assembly.

8. The staged filling completion device according to claim 6, characterized in that: The surface of the elastic split claw (4) has a protrusion, and the upper end of the lifting short section (3) is further provided with a limiting groove (2), and when the first sealing component is in the second position, the protrusion is embedded in the limiting groove (2).

9. The staged filling completion device according to claim 6, characterized in that: The upper joint (1), the lifting nipple (3), the central pipe (11) and the lower joint (15) are fixedly connected by threaded engagement.

10. The staged filling completion device according to claim 1, characterized in that: There are two positioning grooves (16) and two elastic positioning keys (21). The two positioning grooves (16) are axially spaced apart on the positioning sleeve (14), and the two elastic positioning keys (21) are axially spaced apart on the elastic positioning tube (20). When the inner filling server is filled into the outer filling server, the elastic positioning key (21) engages with the positioning groove (16).

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