Multi-seal casing joint

Abstract

The present invention relates to a multi-seal casing patching device, which comprises an outer tube (1) and a guide shoe (2). The lower end of the outer tube (1) is connected to the upper end of the guide shoe (2). A lower sealing ring (22) is provided on the inner wall of the guide shoe (2). A lower spacer ring (3), a lead seal ring (4), an upper spacer ring (5), a control card (6) and an inner tube (7) are provided in the outer tube (1) in order from the guide shoe (2) upward. An upper sealing ring (13) is provided on the inner wall of the outer tube (1) above the inner tube (7). A spiral slip (8) is provided in the inner tube (7). A key mounted on the inner tube (7) is provided at the lower end of the spiral slip (8). A card block (61) mounted on the inner tube (7) is provided on the control card (6). A key block (72) is provided between the inner tube (7) and the outer tube (1). The multi-seal casing patching device combines the advantages of existing rubber seal casing patching devices and metal lead seal casing patching devices, adopts a triple sealing structure, has a better sealing effect, a longer service life and a more compact structure.

Description

Technical Field

[0001] The invention relates to a petroleum tool, in particular to a multi-seal casing connector. Background Art

[0002] The casing patching device is a connector between the old and new casings when the damaged casing is removed from the well and the new casing is lowered. It can keep the inner diameter of the casing unchanged and play a sealing role. At present, a type of packer casing patching device used in oil fields is sealed with rubber seals. Although the rubber seal has a good sealing effect, its sealing effect has a certain time limit and its general working life is difficult to exceed ten years. Another type of lead-sealed casing patching device uses metal lead to deform under pressure to seal the annulus and produce a sealing effect. Although the lead seal can have a long sealing life, due to structural limitations, the outer diameter of this type of casing patching device is designed to be relatively large, which limits its use in locations with smaller annuli. Summary of the invention

[0003] The object of the present invention is to provide a multi-seal casing jointer which has good sealing effect, long service life, more compact structure and can be used without restriction in locations with small annular spaces.

[0004] The technical solution of the present invention is: it comprises an outer tube and a guide shoe, the upper end of the outer tube is provided with an internal thread connected to the casing, the lower end of the outer tube is axially connected to the upper end of the guide shoe through a thread, a lower sealing ring groove is provided on the inner wall of the guide shoe, a lower sealing ring which is sealed and matched with the old casing is provided in the lower sealing ring groove, a lower spacer ring, a lead sealing ring, an upper spacer ring, a control card and an inner tube whose outer wall matches with the inner wall of the outer tube are provided in sequence from the guide shoe upward, the lower end face of the lower spacer ring matches with the upper end face of the guide shoe, the upper end face of the inner tube matches with the inner end face of the outer tube facing downward, and the inner end face of the outer tube at the upper position of the inner tube is matched with the lower end face of the outer tube. An upper sealing ring groove is provided on the wall, and an upper sealing ring is provided in the upper sealing ring groove for sealing with the old casing. The inner wall of the inner cylinder is a conical spiral surface which is thick at the top and thin at the bottom. The inner cylinder is provided with a spiral cava whose outer wall cooperates with the conical spiral surface of the inner cylinder. The lower end of the spiral cava is provided with a key installed in a keyway on the inner cylinder to prevent the lower end of the spiral cava from axially moving inside the inner cylinder. The control card is provided with a block installed in the keyway on the inner cylinder and cooperates with the lower end of the spiral cava to prevent the spiral cava from rotating in the inner cylinder. A key block is provided between the inner cylinder and the outer cylinder to prevent the inner cylinder from rotating in the outer cylinder.

[0005] The technical effect of the present invention is that it combines the advantages of the existing rubber seal casing patching device and the metal lead seal casing patching device, adopts a triple seal structure, has a better sealing effect, a longer service life, and a more compact structure. Since the outer diameter can be designed to be smaller, it can be used in a location with a smaller annulus, and the use occasions are no longer restricted, and has an ideal use effect and application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a cross-sectional structural diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0007] like Figure 1 As shown, it comprises an outer tube 1 and a guide shoe 2, the upper end of the outer tube 1 is provided with an internal thread 11 connected to the casing, the lower end of the outer tube 1 is axially connected to the upper end of the guide shoe 2 through a thread, a lower sealing ring groove 21 is provided on the inner wall of the guide shoe 2, a lower sealing ring 22 which is sealed and matched with the old casing is provided in the lower sealing ring groove 21, and a lower spacer ring 3, a lead sealing ring 4, an upper spacer ring 5, a control card 6 and an inner tube 7 whose outer wall matches the inner wall of the outer tube 1 are provided in sequence from the guide shoe 2 upwards in the outer tube 1, the lower end face of the lower spacer ring 3 matches the upper end face of the guide shoe 2, the upper end face of the inner tube 7 matches the inner end face of the outer tube 1 facing downwards, and an upper sealing ring 22 is provided on the inner wall of the outer tube 1 above the inner tube 7 A sealing ring groove 12 is provided in the upper sealing ring groove 12 with an upper sealing ring 13 that seals with the old sleeve. The inner wall of the inner cylinder 7 is a conical spiral surface that is thick at the top and thin at the bottom. The inner cylinder 7 is provided with a spiral cava 8 whose outer wall cooperates with the conical spiral surface of the inner cylinder 7. The lower end of the spiral cava 8 is provided with a key installed in a key groove 71 on the inner cylinder 7 to prevent the lower end of the spiral cava 8 from axially moving inside the inner cylinder 7. The control card 6 is provided with a block 61 that is installed in the key groove 71 on the inner cylinder 7 and cooperates with the lower end of the spiral cava 8 to prevent the spiral cava 8 from rotating in the inner cylinder 7. A key block 72 is provided between the inner cylinder 7 and the outer cylinder 1 to prevent the inner cylinder 7 from rotating in the outer cylinder 1.

[0008] The upper end of the guide shoe 2 is axially connected to the lower end of the outer tube 1 through an external thread. A sealing ring groove is provided on the outer wall of the guide shoe 2 below the external thread. An O-ring 23 is installed in the sealing ring groove to seal with the inner wall of the outer tube 1.

[0009] The lower sealing ring groove 21 is an annular dovetail groove, and the lower sealing ring 22 is a single-lip rubber sealing ring with a single sealing lip with an edge facing upwards provided on the inner wall at the lower opening.

[0010] The upper sealing ring groove 12 is an annular dovetail groove, and the upper sealing ring 13 is a double-lip rubber sealing ring with a lower sealing lip with an upward edge on the inner wall at the lower opening and an upper sealing lip with a downward edge on the inner wall at the upper opening.

[0011] A pressure test threaded hole 14 and an exhaust threaded hole 15 are radially provided on the side wall of the outer cylinder 1 between the upper end of the inner cylinder 7 and the upper sealing ring groove 12. Threaded plugs 16 are respectively installed in the pressure test threaded hole 14 and the exhaust threaded hole 15 through threads.

[0012] The conical helical surface on the inner wall of the inner cylinder 7 is a left-handed large-pitch conical helical surface.

[0013] The spiral slip 8 is a spring-shaped spiral body. The conical spiral surface on the outer wall of the spiral slip 8 is a left-handed large-pitch conical spiral surface that matches the inner wall of the inner tube 7. The inner wall of the spiral slip 8 is provided with a left-handed salvage thread that matches the outer wall of the casing. The inner diameter of the position where the spiral slip 8 is provided with the left-handed salvage thread is 2-3mm smaller than the outer diameter of the old casing. The spiral slip 8 uses the conical spiral surface on the inner wall of the inner tube 7 to tighten and grab the old casing.

[0014] The outer wall at the upper end of the inner cylinder 7 and the inner wall at the corresponding position of the outer cylinder 1 are respectively provided with matching arc-shaped key grooves, and the key block 72 is an arc-shaped block installed in the key grooves of the outer cylinder 1 and the inner cylinder 7. The key block 72 prevents the outer cylinder 1 and the inner cylinder 7 from rotating relative to each other, and the inner cylinder 7 can only maintain a certain range of up and down movement in the outer cylinder 1, so as to achieve the purpose of compressing the lead sealing ring 4.

[0015] The control card 6 is composed of a block 61 and a snap ring 62. The snap ring 62 is an annular body whose outer wall matches the inner wall of the outer cylinder 1. The block 61 is arranged on the upper end surface of the snap ring 62 and is installed in the keyway 71 at the lower end of the inner cylinder 7 to prevent the control card 6 from rotating relative to the inner cylinder 7. At the same time, it matches with the lower end of the spiral slip 8 to prevent the spiral slip 8 from rotating in the inner cylinder 7. The block 61 of the control card 6 and the key of the spiral slip 8 are respectively installed in the keyway 71 at the lower end of the inner cylinder 7, so that the spiral slip 8 cannot rotate in the inner cylinder 7. The outer wall of the spiral slip 8 matches with the conical spiral surface of the inner cylinder 7, so that the spiral slip 8 can only move up and down in a small range in the inner cylinder 7, so as to achieve the purpose of expanding and contracting the spiral slip 8.

[0016] A protective sleeve 9 is provided inside the outer cylinder 1 and is located above the inner cylinder 7 to protect the upper sealing ring 13 . The protective sleeve 9 is an annular body whose outer wall is axially slidably matched with the inner wall of the outer cylinder 1 .

[0017] The inner diameter of the outer cylinder 1 above the sheath 9 is smaller than the outer diameter of the sheath 9 , so as to limit the sheath 9 .

[0018] The inner diameters of the guide shoe 1, the lower spacer ring 3, the lead sealing ring 4, the upper spacer ring 5, the control card 6 and the inner tube 7 are larger than the outer diameter of the old casing.

[0019] Features:

[0020] 1. Compared with the old-fashioned casing patching device, the multi-seal casing patching device designs the upper joint and the cylinder as an integral part---the outer cylinder 1, thereby eliminating the rubber seal between the upper joint and the cylinder, avoiding the possibility of leakage between the upper joint and the cylinder due to failure of the rubber seal.

[0021] 2. A double-lip rubber sealing ring is installed below the internal thread 11 at the upper end of the outer tube 1 to form the first bidirectional seal between the new and old casings.

[0022] 3. Below the control card 6, a lead sealing ring 4 is designed between the upper spacer ring 5 and the lower spacer ring 3, which forms a second bidirectional seal between the new and old casings through extrusion deformation.

[0023] 4. A single-lip rubber sealing ring is installed on the inner wall of the guide shoe 2 to form a third two-way seal between the new and old casings.

[0024] 5. Among the three seals, the first and third seals are made of high-quality rubber materials. In the initial stage, the sealing performance is reliable and can seal the annulus of new and old casings alone, but there is a risk of aging and failure. The second seal is made of lead, which is not easy to fail and can extend the sealing service life of the casing jointer.

[0025] Working principle:

[0026] When the multi-seal casing jointer connected to the lower end of the new casing approaches the downhole casing, it slowly rotates and slowly lowers (if there is no resistance, the pipe string can be rotated without rotating). After the downhole casing enters the guide shoe 2, it enters the lower sealing ring 22 (single-lip rubber sealing ring) and the spiral slip 8 in turn. The spiral slip 8 is first pushed up in a small range, and then expanded by the casing to allow the casing to pass. After the casing passes through the spiral slip 8, it continues to move upward and enters the upper sealing ring 13 (double-lip rubber sealing ring), pushing the sheath 9 to push it against the outer tube 1. The upper sealing ring 13 clamps the outer wall of the casing to achieve sealing and complete the entry of the fish.

[0027] After the fish is put in, the pipe column is lifted. Since the inner diameter of the spiral slip 8 is 2-3mm smaller than the outer diameter of the casing in its natural state, the spiral slip 8 bites the casing by elastic force and does not move. The pipe column drives the other parts of the multi-seal casing patching device upward. The outer wall of the spiral slip 8 cooperates with the conical spiral surface of the inner tube 7 to make the spiral slip 8 produce an inward contraction force. The greater the lifting load, the tighter the fishing thread of the spiral slip 8 bites the outer wall of the casing. At this time, continue to add force to lift the pipe column, driving the multi-seal casing patching device to move upward. Since the spiral slip 8 limits the upward movement of the inner tube 7, the inner tube 7 produces axial compression on the lead seal ring 4 through the control card 6, the upper spacer ring 5 and the lower spacer ring 3, causing the lead seal ring 4 to expand radially. When the pulling force of the lifting pipe column reaches or exceeds the required pulling force, the lead seal ring 4 seals the annulus between the outer wall of the old casing and the inner wall of the outer tube 1, that is, the sealing between the new and old casings is achieved.

[0028] According to the needs of construction, if the tool needs to be withdrawn and the caught downhole casing needs to be released, the tool can be withdrawn by striking the pipe string downward, then slowly rotating rightward while lifting the tool pipe string. The purpose of striking downward is to make the conical spiral surface of the spiral slip 8 separate from the conical spiral surface of the inner tube 7. The purpose of rotating rightward is to utilize the friction between the spiral slip 8 and the downhole casing to keep the spiral slip 8 in an expanded state at all times, so as to facilitate the withdrawal of the downhole pipe string.

Claims

1. A multi-seal casing jointer, comprising an outer tube (1) and a guide shoe (2), wherein the upper end of the outer tube (1) is provided with an internal thread (11) connected to the casing, and the lower end of the outer tube (1) is axially connected to the upper end of the guide shoe (2) through a thread, characterized in that: The inner wall of the guide shoe (2) is provided with a lower sealing ring groove (21), and a lower sealing ring (22) is provided in the lower sealing ring groove (21) for sealing with the old casing. The outer tube (1) is provided with a lower spacer ring (3) whose outer wall is matched with the inner wall of the outer tube (1), a lead sealing ring (4), an upper spacer ring (5), a control card (6) and an inner tube (7) in sequence from the guide shoe (2) upward. The lower end surface of the lower spacer ring (3) is matched with the upper end surface of the guide shoe (2), and the upper end surface of the inner tube (7) is An upper sealing ring groove (12) is provided on the inner wall of the outer cylinder (1) above the inner cylinder (7) so as to match the inner end surface of the outer cylinder (1) facing downwards. An upper sealing ring (13) which is sealed and matched with the old sleeve is provided in the upper sealing ring groove (12). The inner wall of the inner cylinder (7) is a conical spiral surface which is thick at the top and thin at the bottom. The inner cylinder (7) is provided with a spiral slip (8) whose outer wall matches the conical spiral surface of the inner cylinder (7). The lower end of the spiral slip (8) is provided with a screw installed in the inner cylinder ( A key is provided in a keyway (71) on the inner cylinder (7) to prevent the lower end of the spiral cava (8) from axially moving inside the inner cylinder (7); a control card (6) is provided with a block (61) installed in the keyway (71) on the inner cylinder (7) and cooperating with the lower end of the spiral cava (8) to prevent the spiral cava (8) from rotating inside the inner cylinder (7); a key block (72) is provided between the inner cylinder (7) and the outer cylinder (1) to prevent the inner cylinder (7) from rotating inside the outer cylinder (1); the inner cylinder ( A pressure test threaded hole (14) and an exhaust threaded hole (15) are radially arranged on the side wall of the outer cylinder (1) between the upper end 7) and the upper sealing ring groove (12), and a threaded plug (16) is respectively installed in the pressure test threaded hole (14) and the exhaust threaded hole (15) through threads. A sheath (9) is arranged in the outer cylinder (1) and is located above the inner cylinder (7) to protect the upper sealing ring (13). The sheath (9) is an annular body whose outer wall is axially slidably matched with the inner wall of the outer cylinder (1).

2. The multi-seal casing joint according to claim 1, characterized in that The upper end of the guide shoe (2) is axially connected to the lower end of the outer cylinder (1) through an external thread, and a sealing ring groove is provided on the outer wall of the guide shoe (2) below the external thread, and an O-shaped sealing ring (23) is installed in the sealing ring groove and is sealed with the inner wall of the outer cylinder (1).

3. The multi-seal casing joint according to claim 1, characterized in that The lower sealing ring groove (21) is an annular dovetail groove, and the lower sealing ring (22) is a single-lip rubber sealing ring with a single sealing lip with an upward edge provided on the inner wall at the lower opening.

4. The multi-seal casing joint according to claim 1, characterized in that The upper sealing ring groove (12) is an annular dovetail groove, and the upper sealing ring (13) is a double-lip rubber sealing ring with a lower sealing lip with an upward edge on the inner wall at the lower opening and an upper sealing lip with a downward edge on the inner wall at the upper opening.

5. The multi-seal casing joint according to claim 1, characterized in that The conical helical surface on the inner wall of the inner cylinder (7) is a left-handed large-pitch conical helical surface.

6. The multi-seal casing joint according to claim 1, characterized in that The spiral slip (8) is a spring-shaped spiral body. The conical spiral surface on the outer wall of the spiral slip (8) is a left-handed large-pitch conical spiral surface that matches the inner wall of the inner tube (7). The inner wall of the spiral slip (8) is provided with a left-handed fishing thread that matches the outer wall of the casing.

7. The multi-seal casing joint according to claim 1, characterized in that The outer wall at the upper end of the inner cylinder (7) and the inner wall at the corresponding position of the outer cylinder (1) are respectively provided with matching arc-shaped key grooves, and the key block (72) is an arc-shaped block installed in the key grooves of the outer cylinder (1) and the inner cylinder (7).

8. The multi-seal casing joint according to claim 1, characterized in that The control card (6) is composed of a card block (61) and a card ring (62). The card ring (62) is an annular body whose outer wall matches the inner wall of the outer tube (1). The card block (61) is arranged on the upper end surface of the card ring (62) and is installed in the keyway (71) at the lower end of the inner tube (7).

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