A spiral downhole sealing tool and ball seat

Abstract

The present invention relates to the field of downhole oil construction, and specifically to a spiral downhole isolation tool and a ball seat. The downhole isolation tool comprises: a center tube with a conical outer surface, the center tube having an axial through hole; an anchoring sealing structure matchingly sleeved on the outer surface of the center tube, the anchoring sealing structure having a first sealing section and an anchoring section, the first sealing section being located at the large end of the center tube, the anchoring section comprising a plurality of slips, the first sealing section comprising a plurality of first spiral sealing rings, the plurality of slips and the plurality of first spiral sealing rings forming an integral structure. The plurality of slips are evenly spread out in the radial direction to achieve a uniform circumferential distribution of the slips, so that the slips are evenly anchored on the inner wall of the entire wellbore, ensuring the uniformity of the radial pressure bearing capacity of the downhole isolation tool and improving the sealing pressure bearing effect. Furthermore, since the sealing sections are first spiral sealing rings nested with each other, the sealing sections of the spiral structure require a certain initial force to expand, which can prevent premature sealing.

Description

Technical Field

[0001] The present invention relates to the field of petroleum downhole construction, and in particular to a spiral downhole isolation tool and a ball seat. Background Art

[0002] During the process of the downhole isolation tool completing the sealing process underground, the slips of the downhole isolation tool will be expanded and squeezed to the inner wall of the wellbore. The slips are generally composed of multiple slip pieces. During the expansion of the slips, due to the uneven force on the slips in the radial direction, the slips will be deployed first at the place with greater force. Since the force on the slips at the first deployed place will continue to increase, the slips at this place will be deployed more, and the slips at other places will be deployed less, resulting in uneven deployment and anchoring of the slips on the inner wall of the entire wellbore, which reduces the radial pressure-bearing capacity of the downhole isolation tool, affects the sealing and pressure-bearing effect of the downhole isolation tool, and further the central pipe will fall out, resulting in isolation failure. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides a spiral downhole isolation tool and a ball seat, so as to improve the axial pressure bearing capacity of the downhole isolation tool.

[0004] The present invention solves the above-mentioned technical problems with the following technical solutions: A spiral downhole isolation tool comprising:

[0005] a central tube with a tapered outer surface and an axial through hole;

[0006] An anchoring sealing structure, the anchoring sealing structure is matched and sleeved on the outer surface of the central tube, the anchoring sealing structure has a first sealing section and an anchoring section, the first sealing section is located at the large end of the central tube, the anchoring section includes a plurality of slips, the first sealing section includes a plurality of first spiral sealing rings, the plurality of slips correspond one-to-one with the plurality of first spiral sealing rings and respectively form an integral structure, the plurality of first spiral sealing rings are nested with each other to form the first sealing section.

[0007] The working principle and beneficial effects of the present invention are as follows: during the downhole isolation tool lowering process, the anchoring sealing structure is caused to move relative to the central pipe and expand radially by the downhole tool. Since the slip ring corresponds to the first spiral sealing ring one by one and forms an integral structure respectively, during the expansion process of the first sealing section, the slip ring is also subjected to its radial expansion force and expands. Among them, a plurality of the first spiral sealing rings are nested with each other to form the first sealing section. In the first sealing section, the radial expansion force received by each first spiral sealing ring is uniform. In this way, each first spiral sealing ring is also uniformly expanded in the radial direction, thereby driving a plurality of the slip rings to be uniformly expanded in the radial direction, achieving circumferential uniform distribution of the slip rings, so that the slip rings are uniformly expanded and anchored on the inner wall of the entire wellbore, ensuring the uniformity of the radial pressure bearing capacity of the downhole isolation tool and improving the sealing pressure bearing effect of the downhole isolation tool. Furthermore, since the sealing section is a first spiral sealing ring nested with each other, the sealing section of the spiral structure requires a certain initial force to expand and expand, which can prevent premature sealing.

[0008] On the basis of the above technical solution, the present invention can also be improved as follows.

[0009] Furthermore, a plurality of the slips are arranged in parallel in the axial direction of the central tube.

[0010] The beneficial effect of adopting the above further solution is that the slips are easily unfolded.

[0011] On the basis of the above technical solution, the present invention can also be improved as follows.

[0012] Furthermore, the gaps between the plurality of slips are parallel to the axis of the central tube and are evenly distributed around the circumference of the central tube.

[0013] The beneficial effect of adopting the above further solution is to ensure that the multiple slips are evenly deployed and form a uniform anchoring force on the inner wall of the wellbore.

[0014] On the basis of the above technical solution, the present invention can also be improved as follows.

[0015] Furthermore, the first spiral sealing ring forms at least one complete sealing length in the circumferential direction on the central tube.

[0016] The beneficial effect of adopting the above further solution is that the first sealing section formed by the multiple first spiral sealing rings has a sufficient sealing length in its radial direction, further improving the reliability of the seal.

[0017] On the basis of the above technical solution, the present invention can also be improved as follows.

[0018] Furthermore, a sealing rubber tube is provided on the central tube, and one end of the sealing rubber tube abuts against the first sealing section.

[0019] The beneficial effect of adopting the above further solution is that resealing is achieved by providing the sealing rubber cylinder.

[0020] On the basis of the above technical solution, the present invention can also be improved as follows.

[0021] Furthermore, a retaining ring is provided on the central tube, and the other end of the sealing rubber tube abuts against the retaining ring.

[0022] The beneficial effect of adopting the above further solution is that the retaining ring prevents the sealing rubber cylinder from expanding axially upward, thereby improving the sealing reliability of the sealing rubber cylinder.

[0023] On the basis of the above technical solution, the present invention can also be improved as follows.

[0024] Furthermore, the retaining ring is a spiral retaining ring.

[0025] The beneficial effects of adopting the above-mentioned further scheme are: the spiral retaining ring spirally expands in the radial direction, and the retaining ring will not break or rupture, thereby improving the axial containment effect of the sealing rubber tube; at the same time, the spiral retaining ring requires a certain initial force to expand, which also prevents the downhole sealing tool from being prematurely sealed.

[0026] On the basis of the above technical solution, the present invention can also be improved as follows.

[0027] Furthermore, a sealing boss is provided on the outer surface of the first spiral sealing ring.

[0028] The beneficial effect of adopting the above further scheme is that when the first spiral sealing ring is subjected to radial pressure, the surface area of ​​the boss is smaller. Under the condition of equal pressure, the pressure at the boss position is greater, making it easy for the boss to squeeze into the inner wall of the wellbore and form a seal with the inner wall of the wellbore, thereby improving the sealing effect.

[0029] On the basis of the above technical solution, the present invention can also be improved as follows.

[0030] Furthermore, anti-retraction structures for mutual locking are provided on the outer surface of the central tube and the inner surface of the anchoring sealing structure.

[0031] The beneficial effect of adopting the above further solution is that by providing an anti-retraction structure, it is ensured that the anchoring sealing structure will not be displaced, thereby improving the reliability of the sealing anchoring.

[0032] On the basis of the above technical solution, the present invention can also be improved as follows.

[0033] Furthermore, the plurality of slips are interconnected at one end away from the first sealing section to form an integral structure.

[0034] The beneficial effect of adopting the above further solution is that the effect of preventing premature seating is further improved.

[0035] The present invention also provides a ball seat, comprising a lower joint and the above-mentioned spiral downhole isolation tool, wherein the lower joint is located at one end of the slip.

[0036] The beneficial effect of the ball seat is as follows: during the downhole isolation tool lowering process, the anchoring sealing structure is caused to move relative to the center pipe and expand radially through the downhole tool. Since the slip ring corresponds to the first spiral sealing ring one by one and forms an integral structure, during the expansion of the first sealing section, the slip ring is also subjected to its radial expansion force and expands. Among them, multiple first spiral sealing rings are nested with each other to form the first sealing section. In the first sealing section, the radial expansion force received by each first spiral sealing ring is uniform. In this way, each first spiral sealing ring is also uniformly expanded in the radial direction, thereby driving multiple slip rings to be uniformly expanded in the radial direction, achieving uniform circumferential distribution of slip rings, so that the slip rings are uniformly expanded and anchored on the inner wall of the entire wellbore, ensuring the uniformity of the radial pressure bearing capacity of the downhole isolation tool and improving the sealing pressure bearing effect of the downhole isolation tool. Furthermore, since the sealing section is a first spiral sealing ring nested with each other, the sealing section of the spiral structure requires a certain initial force to expand and expand, which can prevent premature sealing. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 1 is a schematic diagram of the three-dimensional structure of a spiral downhole isolation tool according to a first embodiment of the present invention;

[0038] Figure 2 is a cross-sectional view in one direction of the first embodiment;

[0039] Figure 3 This is a schematic diagram of the first working state of Example 1;

[0040] Figure 4 This is a schematic diagram of the second working state of Example 1;

[0041] Figure 5 1 is a schematic diagram of the three-dimensional structure of a second embodiment of a spiral downhole isolation tool according to the present invention;

[0042] Figure 6 is a cross-sectional view of embodiment 2 in one direction;

[0043] Figure 7 This is a schematic diagram of the first working state of the second embodiment;

[0044] Figure 8 This is a schematic diagram of the second working state of the second embodiment;

[0045] Figure 9 This is a schematic diagram of the second working state of Example 3;

[0046] Figure 10 This is a schematic diagram of the second working state of the fourth embodiment;

[0047] Figure 11 is a schematic diagram of the three-dimensional structure of embodiment 5;

[0048] Figure 12 It is a cross-sectional view of embodiment 6 in one direction.

[0049] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0050] 1. Central pipe, 2. Anchoring seal structure, 21. First sealing section, 211. First spiral sealing ring, 22. Anchoring section, 221. Slip, 222. Slip teeth, 23. Second sealing section, 231. Second spiral sealing ring, 3. Sealing rubber tube, 4. Retaining ring, 5. Wellbore. DETAILED DESCRIPTION

[0051] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0052] The structural diagram of the spiral downhole isolation tool embodiment 1 of the present invention is shown in FIG. Figures 1 to 4 .

[0053] In this embodiment, a central tube 1 having a conical outer surface and an axial through hole is provided; an anchoring sealing structure 2 is provided, and the anchoring sealing structure 2 is matched and sleeved on the outer surface of the central tube 1. The anchoring sealing structure 2 has a first sealing section 21 and an anchoring section 22. The first sealing section 21 is located at the large end of the central tube 1. The anchoring section 22 includes a plurality of slips 221. The first sealing section 21 includes a plurality of first spiral sealing rings 211. The plurality of slips 221 correspond one-to-one to the plurality of first spiral sealing rings 211 and respectively form an integral structure. The plurality of first spiral sealing rings 211 are nested with each other to form the first sealing section 21.

[0054] Five slips 221 are arranged axially parallel to the center tube 1, with the gaps between the slips 221 parallel to the axis of the center tube 1 and evenly distributed around the circumference of the center tube 1. This corresponds to five first spiral sealing rings 211, which are nested together to form the first sealing section 21. Each slip 221 is equipped with nine slip teeth 222.

[0055] The working principle and beneficial effects of this embodiment are as follows: during the downhole isolation tool running into the well, the anchoring sealing structure 2 is caused to move relative to the central pipe 1 and expand in the radial direction by the downhole tool. Since the slips 221 correspond one-to-one with the first spiral sealing ring 211 and form an integral structure respectively, during the expansion of the first sealing section 21, the slips 221 are also expanded by their radial expansion force; wherein, the five first spiral sealing rings 211 are nested with each other to form the first sealing section 21, and the radial expansion force exerted on each first spiral sealing ring 211 in the first sealing section 21 is uniform, so that each first spiral sealing ring 211 is also uniformly expanded in the radial direction, thereby driving multiple slips 221 to be uniformly expanded in the radial direction, realizing circumferential uniform distribution of the slips, so that the slips 221 are evenly anchored on the inner wall of the entire wellbore, ensuring the uniformity of the radial pressure-bearing capacity of the downhole isolation tool and improving the sealing pressure-bearing effect of the downhole isolation tool. Furthermore, since the sealing sections are nested first spiral sealing rings 211, the spirally structured sealing sections require a certain initial force to expand, thereby preventing premature setting.

[0056] The plurality of slips 221 are evenly distributed around the circumference of the central pipe 1 to ensure that the plurality of slips are evenly deployed and form a uniform anchoring force on the inner wall of the wellbore. In this embodiment, a step is provided between the first sealing section 21 and the anchoring section 22.

[0057] The structural diagram of the spiral downhole isolation tool embodiment 2 of the present invention is shown in FIG. Figures 5 to 8 .

[0058] A spiral downhole isolation tool comprises a central pipe 1 with a conical outer surface and an axial through hole.

[0059] Anchoring sealing structure 2, the anchoring sealing structure 2 is matched and sleeved on the outer surface of the central tube 1, the anchoring sealing structure 2 has a first sealing section 21 and an anchoring section 22, the first sealing section 21 is located at the large end of the central tube 1, the anchoring section 22 includes a plurality of slips 221, the first sealing section 21 includes a plurality of first spiral sealing rings 211, the plurality of slips 221 correspond one-to-one to the plurality of first spiral sealing rings 211 and respectively form an integral structure, and the plurality of first spiral sealing rings 211 are nested with each other to form the first sealing section 21.

[0060] In this embodiment, there are five slips 221, that is, there are also five corresponding first spiral sealing rings 211. The five first spiral sealing rings 211 are nested with each other to form the first sealing section 21. Each slip 221 is provided with nine slip teeth 222.

[0061] The working principle and beneficial effects of this embodiment are as follows: during the downhole isolation tool running into the well, the anchoring sealing structure 2 is caused to move relative to the central pipe 1 and expand in the radial direction by the downhole tool. Since the slips 221 correspond one-to-one with the first spiral sealing ring 211 and form an integral structure respectively, during the expansion of the first sealing section 21, the slips 221 are also expanded by their radial expansion force; wherein, the five first spiral sealing rings 211 are nested with each other to form the first sealing section 21, and the radial expansion force exerted on each first spiral sealing ring 211 in the first sealing section 21 is uniform, so that each first spiral sealing ring 211 is also uniformly expanded in the radial direction, thereby driving multiple slips 221 to be uniformly expanded in the radial direction, realizing circumferential uniform distribution of the slips, so that the slips 221 are evenly anchored on the inner wall of the entire wellbore, ensuring the uniformity of the radial pressure-bearing capacity of the downhole isolation tool and improving the sealing pressure-bearing effect of the downhole isolation tool. Furthermore, since the sealing sections are nested first spiral sealing rings 211, the spirally structured sealing sections require a certain initial force to expand, thereby preventing premature setting.

[0062] In this embodiment, if Figure 8 As shown, when the five first spiral sealing rings 211 are nested with each other to form a first sealing section 21 that is sealed and connected to the inner wall of the wellbore 5 , the slip teeth 222 on the slips 221 are anchored to the inner wall of the wellbore 4 .

[0063] In this embodiment, the five first spiral sealing rings 211 are located in the same plane at the ends, ensuring that the pressure of the well fluid on the anchoring sealing structure 2 is balanced after setting.

[0064] In this embodiment, the anchoring sealing structure 2 also has a second sealing section 23, which is located at the other end of the anchoring section 22 (i.e., the right position in the figure). The second sealing section 23 includes multiple second spiral sealing rings 231, and corresponds one-to-one with multiple cavas 221 and forms an integral structure respectively. The multiple second spiral sealing rings 231 are nested with each other to form the second sealing section 23.

[0065] The second sealing section 23 is provided to achieve a multi-stage sealing effect of the downhole isolation tool, thereby improving the sealing reliability.

[0066] The structural diagram of the third embodiment of the present invention is shown in FIG. Figure 9 In this embodiment, the difference from the first embodiment is that a sealing rubber tube 3 and a retaining ring 4 are provided on the central tube 1. One end of the sealing rubber tube 3 abuts against the first sealing section 21, and the other end of the sealing rubber tube 3 abuts against the retaining ring 4. The retaining ring 4 is a spiral retaining ring.

[0067] The provision of the sealing rubber sleeve 3 achieves multi-stage sealing. Simultaneously, the retaining ring 4 prevents the sealing rubber sleeve 3 from axially expanding, thereby improving the sealing reliability of the sealing rubber sleeve 3. Furthermore, the spiral retaining ring expands radially without breaking or cracking, thus enhancing the axial containment of the sealing rubber sleeve 3. Because the spiral retaining ring requires a certain radial pressure during expansion, it further enhances the effectiveness of preventing premature setting.

[0068] The sealing rubber tube 3 may be a soluble sealing rubber tube that is easily soluble in the downhole environment. The retaining ring 4 may also be a soluble metal that is easily soluble in the downhole environment.

[0069] The structural diagram of the fourth embodiment of the present invention is shown in FIG. Figure 10 In this embodiment, the difference from the second embodiment is that a sealing rubber tube 3 and a retaining ring 4 are provided on the central tube 1. One end of the sealing rubber tube 3 abuts against the first sealing section 21, and the other end of the sealing rubber tube 3 abuts against the retaining ring 4. The retaining ring 4 is a spiral retaining ring.

[0070] In a specific embodiment, a sealing boss is provided on the outer surface of the first spiral sealing ring 211 .

[0071] When the first spiral sealing ring 211 is subjected to radial pressure, the surface area of ​​the boss is small. Under the condition of equal pressure, the pressure at the boss position is greater, making it easy for the boss to squeeze into the inner wall of the wellbore 5 and form a seal with the inner wall of the wellbore, thereby improving the sealing effect.

[0072] In a specific embodiment, a sealing boss may also be provided on the outer surface of the second spiral sealing ring 231 .

[0073] Similarly, when the second spiral sealing ring 231 is subjected to radial pressure, the surface area of ​​the boss is smaller. Under the same pressure conditions, the boss is subjected to greater pressure, making it easy for the boss to squeeze into the inner wall of the wellbore and form a seal with the inner wall of the wellbore, thereby improving the sealing effect.

[0074] In a specific embodiment, anti-retraction structures (not shown) are provided on the outer surface of the base pipe 1 and the inner surface of the anchor seal 2 for interlocking. Specifically, the anti-retraction structures are intermeshing concave-convex structures. When the spiral downhole isolation tool completes the seal anchoring, the outer surface of the base pipe 1 and the inner surface of the anchor seal 2 engage and lock with each other through the concave-convex structures, preventing axial displacement between them. This ensures that the anchor seal does not move, improving the reliability of the seal anchoring.

[0075] The present invention further provides an embodiment of a ball seat, which includes a lower joint and the above-mentioned spiral downhole isolation tool, wherein the lower joint is located at one end of the slip 221.

[0076] When the specific product is working, the adapter is fixed to the lower joint, the slips 221 are pushed to move by the tool, and the central pipe is pushed by the push tube to anchor and seal the anchoring sealing structure to the inner wall of the wellbore.

[0077] The structural diagram of the fifth embodiment of the present invention is shown in FIG. Figure 11 The structure of this embodiment is different from that of the first embodiment in that a plurality of cavas 221 are arranged as an integrated structure connected to each other at the end away from the first sealing section 21 (the lower right end face in the figure is an integrated structure), which further improves the effect of preventing premature sealing.

[0078] The cross-sectional view of the sixth embodiment of the present invention in one direction is shown in FIG. Figure 12 The structure of this embodiment is different from that of the first embodiment in that no step is provided between the first sealing segment 21 and the anchoring segment 22 .

[0079] In a specific embodiment, in order to match the corresponding downhole isolation tool of the second embodiment, the lower joint is located at one end of the second sealing section 23 .

[0080] In a specific embodiment, the total number of the first spiral sealing ring 211 , the second spiral sealing ring 231 and the slips 221 can be adjusted according to actual use needs.

[0081] In a specific embodiment, the length of the first spiral sealing ring 211 can be set to at least one turn. In this way, the first sealing segment 21 formed by multiple first spiral sealing rings 211 has sufficient sealing length in its radial direction, further improving the reliability of the seal. Similarly, the length of the second spiral sealing ring 231 can be set to at least one turn. In this way, the second sealing segment 23 formed by multiple second spiral sealing rings 231 has sufficient sealing length in its radial direction, ensuring the reliability of the seal.

[0082] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A spiral downhole isolation tool, characterized in that: include: A central tube (1) with a tapered outer surface, the central tube (1) having an axial through hole; An anchoring sealing structure (2), wherein the anchoring sealing structure (2) is matched and sleeved on the outer surface of the central tube (1), and the anchoring sealing structure (2) comprises a first sealing section (21) and an anchoring section (22), wherein the first sealing section (21) is located at the large end of the central tube (1), and the anchoring section (22) comprises a plurality of slips (221), and the first sealing section (21) comprises a plurality of first spiral sealing rings (211), wherein the plurality of slips (221) correspond one-to-one to the plurality of first spiral sealing rings (211) and respectively form an integral structure, and the plurality of first spiral sealing rings (211) are nested with each other to form the first sealing section (21).

2. A spiral downhole isolation tool according to claim 1, characterized in that: The plurality of slips (221) are arranged in parallel in the axial direction of the central tube (1).

3. A spiral downhole isolation tool according to claim 2, characterized in that: The gaps between the plurality of slips (221) are parallel to the axis of the central tube (1) and are evenly distributed in the circumferential direction of the central tube (1).

4. The spiral downhole isolation tool according to claim 1, characterized in that: The first spiral sealing ring (211) forms at least one complete sealing length in the circumferential direction of the central tube (1).

5. A spiral downhole isolation tool according to any one of claims 1 to 4, characterized in that: A sealing rubber tube (3) is provided on the central tube (1), and one end of the sealing rubber tube (3) abuts against the first sealing section (21).

6. The spiral downhole isolation tool according to claim 5, characterized in that: A retaining ring (4) is provided on the central tube (1), and the other end of the sealing rubber tube (3) abuts against the retaining ring (4).

7. The spiral downhole isolation tool according to claim 6, characterized in that: The retaining ring (4) is a spiral retaining ring.

8. The spiral downhole isolation tool according to any one of claims 1 to 4, characterized in that: A sealing boss is provided on the outer surface of the first spiral sealing ring (211).

9. The spiral downhole isolation tool according to any one of claims 1 to 4, characterized in that: Anti-retraction structures for mutual locking are provided on the outer surface of the central tube (1) and the inner surface of the anchoring sealing structure (2).

10. The spiral downhole isolation tool according to any one of claims 1 to 4, characterized in that: The plurality of slips (221) are connected to each other at one end away from the first sealing section (21) to form an integral structure.

11. A ball seat, characterized in that: It comprises a lower joint and the spiral downhole isolation tool according to any one of claims 1 to 10, wherein the lower joint is located at one end of the slip (221).

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