Soluble key to open multi-stage fracturing sliding sleeve

Abstract

The application provides a soluble key opening multistage fracturing sliding sleeve, and relates to the technical field of oil and gas field operation construction tools.The multistage fracturing sliding sleeve belongs to a separate layer fracturing tool, can be used for multistage fracturing of a cementing string or in-hole separate layer fracturing; wherein, the solid structure of the soluble key meets the high-pressure construction strength requirement; after the fracturing construction is completed, the soluble key is completely dissolved, and the requirement of the large-diameter multistage fracturing sliding sleeve is met; meanwhile, a structure similar to a lock core is designed in the sliding sleeve, only the corresponding soluble key can successfully open the sliding sleeve, through this principle, various keys and various lock cores can be designed, one key corresponds to one lock core, the same size fracturing sliding sleeve can meet the fracturing construction requirements of dozens of layer positions, after the fracturing is completed, the soluble key is automatically dissolved, the inner diameters of all the sliding sleeves are the same, and thus the full-diameter sliding sleeve target is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas field operation construction tools, in particular to a multi-stage fracturing sliding sleeve opened by soluble key. BACKGROUND

[0002] Multi-layer fracturing is the main means for increasing production and reconstruction of tight oil reservoirs at present. Special tools are needed for staged fracturing. The main staged fracturing tools at present are coiled tubing drag fracturing tools, ball sliding sleeve fracturing tools, and infinite extreme fracturing sliding sleeve tools. Coiled tubing drag fracturing requires coiled tubing equipment, and is shot through the casing by means of sandblasting perforation, which is not conducive to offshore platform operation, and there are problems of difficult control of perforation quality and long operation time.

[0003] Among them, the ball sliding sleeve is a relatively mature fracturing tool, and the ball seat is gradually reduced in diameter, so that the fracturing stage number is limited by the inner diameter size. For small size tubular column, it is difficult to achieve the staged fracturing target of multiple layers due to the small inner diameter.

[0004] And the infinite extreme fracturing sliding sleeve is opened by a soluble ball with an elastic pawl sleeve. In actual application, there are the following two problems:

[0005] 1. The elastic pawl itself has low strength, and when high pressure (≥70 MPa) is applied, the soluble ball exerts a large thrust on the elastic pawl, which can reach tens of tons, and the pawl sleeve is easily crushed;

[0006] 2. After the fracturing operation is completed, the soluble ball dissolves, but the elastic pawl sleeve is not soluble, and the inner diameter of the elastic pawl sleeve is the inner diameter of the multi-stage fracturing sliding sleeve, which cannot meet the requirements of the large-diameter multi-stage fracturing sliding sleeve.

[0007] To solve the above problems, we propose a multi-stage fracturing sliding sleeve opened by soluble key to solve the above problems. SUMMARY

[0008] To solve the problems in the background art, the present application provides a multi-stage fracturing sliding sleeve opened by soluble key.

[0009] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0010] The application discloses a soluble key opening multistage fracturing sliding sleeve, which comprises an upper joint and a lower joint installed at the right end of the upper joint; the upper joint is threadedly connected with the lower joint and is locked through a plurality of sets of locking pins; two sets of second sealing elements are arranged at the connection position of the upper joint and the lower joint and are used for sealing the connection of the upper joint and the lower joint; a core sleeve is arranged in the inner cavity of the upper joint; four sets of first sealing elements are arranged on the left side of the outer surface of the core sleeve; a blocking sleeve is connected to the right end of the core sleeve and is locked through a plurality of sets of shearing pins; and the blocking sleeve is arranged in the inner cavity of the lower joint.

[0011] A plurality of sets of locking blocks are circumferentially and uniformly arranged at the middle portions of the two ends of the core sleeve; two sets of elastic sheets are arranged on the middle portions of the outer surfaces of the locking blocks; the outer walls of the elastic sheets are in contact with the inner cavity of the upper joint; a soluble key is arranged in the inner cavity of the core sleeve; and the soluble key is clamped to the inner side of the middle portion of the locking block.

[0012] Preferably, the left end opening of the upper joint is provided with an internal thread structure, the right end opening surface of the upper joint is provided with an external thread structure, and two sets of first sealing installation grooves are formed at the right side of the external thread structure, and the two sets of second sealing elements are respectively arranged in the two sets of first sealing installation grooves.

[0013] Preferably, a through liquid hole is formed in the middle portion of the left end of the upper joint, and when the core sleeve is arranged at the left side of the inner cavity of the upper joint, the through liquid hole is sealed.

[0014] Preferably, the inner hole of the lower joint is provided with a double-step structure, the right side of the inner hole of the lower joint is provided with a limiting groove, a plurality of sets of pin thread holes are circumferentially and uniformly formed in the left end of the lower joint, the left end opening of the lower joint is provided with an internal thread structure, and the right end outer surface of the lower joint is provided with an external thread structure.

[0015] Preferably, the left end of the core sleeve is provided with four sets of second sealing installation grooves, four sets of the first sealing elements are respectively arranged in the four sets of second sealing installation grooves, a plurality of sets of countersunk long strip holes are arranged in the middle portion of the core sleeve, and the locking blocks are arranged in the countersunk long strip holes.

[0016] Preferably, the right end of the core sleeve is provided with a plurality of sets of shearing pin thread holes and a blocking ring groove, the blocking ring groove is arranged at the right side of the shearing pin thread hole, and an elastic blocking ring is arranged in the blocking ring groove.

[0017] Preferably, the outer surface of the locking block is provided with two sets of elastic sheet grooves, two sets of the elastic sheets are respectively arranged in the two sets of elastic sheet grooves, and two sets of tooth grooves are arranged on the right side of the inner wall of the locking block.

[0018] Preferably, the outer surface of the soluble key is provided with a sealing groove at both ends, a V-shaped seal is installed in the middle of the inner side of the sealing groove, and the middle of the soluble key is provided with two groups of lock teeth.

[0019] Preferably, the left end surface of the blocking sleeve is provided with a locking groove; when the blocking sleeve is installed at the right end of the core sleeve, the locking groove is located on the inner side of the shear pin threaded hole and is in an overlapping state, and the shear pin is inserted into the locking groove through the shear pin threaded hole, so that the connection of the core sleeve and the blocking sleeve is locked.

[0020] Preferably, the main body of the first seal and the second seal is a sealing ring, and a sealing ring retainer is arranged at both ends of the sealing ring.

[0021] Compared with the prior art, the beneficial effects of the present application are:

[0022] The soluble key opening multi-stage fracturing sliding sleeve of the present application belongs to a layered fracturing tool, and can be used for multi-stage fracturing of a cementing string or in-hole layered fracturing. The soluble key opening multi-stage fracturing sliding sleeve is opened by a soluble key, wherein the soluble key has a solid structure, meets the high pressure (≥70 MPa) construction strength requirement, and is completely dissolved after fracturing construction, meeting the requirement of large-diameter multi-stage fracturing sliding sleeve.

[0023] Meanwhile, a structure similar to a lock core is designed in the sliding sleeve, and only the corresponding soluble key can successfully open it. According to this principle, a plurality of keys and a plurality of lock cores can be designed, one key corresponds to one lock core, and the same size fracturing sliding sleeve can meet the fracturing construction requirement of dozens of layers, and the soluble key is dissolved automatically after fracturing, and the inner diameters of all sliding sleeves are the same, so as to achieve the goal of full sliding sleeve diameter. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a closed state sectional view of the multi-stage fracturing sliding sleeve of the present application;

[0025] Figure 2 It is an open state sectional view of the multi-stage fracturing sliding sleeve of the present application;

[0026] Figure 3 It is a sectional view of the upper joint in the present application;

[0027] Figure 4 It is a sectional view of the lower joint in the present application;

[0028] Figure 5 It is a sectional view of the core sleeve in the present application;

[0029] Figure 6 It is a sectional view of the blocking sleeve in the present application;

[0030] Figure 7 A sectional view of the soluble key in the present application;

[0031] Figure 8 A sectional view of the lock block in the present application;

[0032] Figure 9 A sectional view of the engagement state of the lock teeth and the tooth groove of the soluble key in the present application.

[0033] In the figure: 1, upper joint; 2, core sleeve; 3, soluble key; 4, lock block; 5, spring piece; 6, blocking sleeve; 7, lower joint; 8, first sealing element; 9, V-shaped seal; 10, set pin; 11, second sealing element; 12, cutting pin; 13, elastic blocking ring;

[0034] 101, first sealing installation groove; 102, liquid passage hole; 201, second sealing installation groove; 202, countersunk long hole; 203, cutting pin threaded hole; 204, blocking ring groove; 301, sealing groove; 302, lock tooth; 401, spring piece groove; 402, tooth groove; 601, locking groove; 701, pin threaded hole; 702, limiting groove. DETAILED DESCRIPTION

[0035] The technical solution in the embodiments of the present application is to solve the problems in the above background art, and the general idea is as follows:

[0036] Embodiment: Referring to Figure 1 - Figure 9 The soluble key opening multi-stage fracturing sliding sleeve of the embodiment includes an upper joint 1 and a lower joint 7 installed at the right end of the upper joint 1. The upper joint 1 is threadedly connected with the lower joint 7 and is locked by a plurality of set pins 10. Two groups of second sealing elements 11 are arranged at the connection between the upper joint 1 and the lower joint 7, and the two groups of second sealing elements 11 are used to seal the connection between the upper joint 1 and the lower joint 7.

[0037] The left end opening of the upper joint 1 is arranged as an internal thread structure, the right end opening surface of the upper joint 1 is arranged as an external thread structure, two groups of first sealing installation grooves 101 are arranged at the right side of the external thread structure, and the two groups of second sealing elements 11 are respectively installed in the two groups of first sealing installation grooves 101.

[0038] The inner hole of the lower joint 7 is arranged as a double-step structure, the right side of the inner hole of the lower joint 7 is arranged as a limiting groove 702, a plurality of pin threaded holes 701 are circumferentially and uniformly arranged at the left end of the lower joint 7, the left end opening of the lower joint 7 is arranged as an internal thread structure, and the right end outer surface of the lower joint 7 is arranged as an external thread structure.

[0039] The inner cavity of the upper joint 1 is provided with a core sleeve 2, the outer surface of the core sleeve 2 is provided with four groups of first sealing pieces 8 on the left side, which play a sealing role, the right end of the core sleeve 2 is connected with a blocking sleeve 6, and is locked through a plurality of shear nails 12, and the blocking sleeve 6 is located in the inner cavity of the lower joint 7; the middle part of the two ends of the core sleeve 2 is uniformly provided with a plurality of lock blocks 4 in a circumferential direction, the outer surface of the lock block 4 is provided with two groups of elastic sheets 5 in the middle part, the outer wall of the elastic sheet 5 is in contact with the inner cavity of the upper joint 1; the inner cavity of the core sleeve 2 is provided with a soluble key 3, the soluble key 3 is clamped in the inner side of the lock block 4, and the elastic sheet 5 plays a role on the lock block 4, so that the soluble key 3 can slide down until it is locked with the lock block 4.

[0040] The left end of the core sleeve 2 is provided with four groups of second sealing installation grooves 201, and the four groups of first sealing pieces 8 are respectively installed in the four groups of second sealing installation grooves 201. The four groups of first sealing pieces 8 play a sealing role, so that the core sleeve 2 is sealingly installed in the inner cavity of the upper joint 1. The middle part of the core sleeve 2 is provided with a plurality of circumferentially distributed countersunk long strip holes 202, and the lock block 4 is installed in the countersunk long strip hole 202.

[0041] The left end of the upper joint 1 is provided with a through type liquid passing hole 102, when the core sleeve 2 is located in the inner cavity of the upper joint 1, the liquid passing hole 102 is sealed, and vice versa, when the core sleeve 2 slides down, the liquid passing hole 102 is leaked.

[0042] In some examples, the right end of the core sleeve 2 is provided with a plurality of shear nail threaded holes 203 and a stop ring groove 204, the stop ring groove 204 is located on the right side of the shear nail threaded hole 203, and the elastic stop ring 13 is installed in the stop ring groove 204, wherein the plurality of shear nail threaded holes 203 are uniformly distributed in a circumferential direction.

[0043] In some examples, the outer surface of the lock block 4 is provided with two groups of elastic sheet grooves 401, and the two groups of elastic sheets 5 are respectively installed in the two groups of elastic sheet grooves 401; the inner wall of the lock block 4 is provided with two groups of tooth grooves 402 on the right side; the outer surface of the soluble key 3 is provided with a sealing groove 301 at both ends, the inner side of the sealing groove 301 is provided with a V-shaped sealing piece 9 in the middle part, and the middle part of the soluble key 3 is provided with two groups of lock teeth 302.

[0044] When the soluble key 3 is installed into the core sleeve 2, the two groups of lock teeth 302 are engaged with the two groups of tooth grooves 402.

[0045] In some examples, the left end surface of the blocking sleeve 6 is provided with a locking groove 601; when the blocking sleeve 6 is installed at the right end of the core sleeve 2, the locking groove 601 is located in the inner side of the shear nail threaded hole 203 at this time, and is in an overlapping mode, the shear nail 12 is inserted into the locking groove 601 through the shear nail threaded hole 203, so that the connection of the core sleeve 2 and the blocking sleeve 6 is locked.

[0046] In some examples, the first seal 8 and the main body of the second seal 11 are both sealing rings, and sealing ring stop rings are arranged at both ends of the sealing rings to improve the sealing effect.

[0047] The working principle of the present application is as follows:

[0048] The sliding sleeve is connected to the completion pipe string on the ground and is lowered into the target layer along with the completion pipe string in use, and the sliding sleeve is in a closed state, and the liquid passage 102 is in a closed state;

[0049] The sliding sleeve is connected to the completion pipe string on the ground and is lowered into the target layer along with the completion pipe string in use, and the sliding sleeve is in a closed state, and the liquid passage 102 is in a closed state;

[0050] Through the above steps, the final state of the sliding sleeve fracturing is completed, wherein after the separate layer fracturing is completed, the soluble key 3 is dissolved automatically, and the inner diameters of all the fracturing sliding sleeves are consistent.

[0051] The basic principle and main features of the present application and the advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principle of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A dissolvable key-opening multistage fracturing sleeve, characterized in that, Including the upper joint (1) and install in the right end of upper joint (1) lower joint (7); The upper joint (1) is connected with the lower joint (7) by screwing, and is locked by a plurality of sets of locking pins (10). Two sets of second sealing elements (11) are arranged at the connection between the upper joint (1) and the lower joint (7), and the two sets of second sealing elements (11) are used for sealing the connection between the upper joint (1) and the lower joint (7). A core sleeve (2) is arranged in the inner cavity of the upper joint (1). Four sets of first sealing elements (8) are arranged on the left side of the outer surface of the core sleeve (2). A blocking sleeve (6) is connected to the right end of the core sleeve (2), and is locked by a plurality of sets of shear pins (12). The blocking sleeve (6) is located in the inner cavity of the lower joint (7). A plurality of sets of locking blocks (4) are evenly arranged on the middle part of the core sleeve (2) in a circumferential direction. Two sets of elastic sheets (5) are arranged on the outer surface of each of the plurality of sets of locking blocks (4). The outer wall of the elastic sheet (5) is in contact with the inner cavity of the upper joint (1). A soluble key (3) is arranged in the inner cavity of the core sleeve (2). The soluble key (3) is clamped on the inner side of the plurality of sets of locking blocks (4).

2. The dissolvable key-opening multi-stage fracturing sleeve of claim 1, wherein, The left end opening of the upper joint (1) is arranged as an internal thread structure. The right end opening surface of the upper joint (1) is arranged as an external thread structure. Two sets of first sealing installation grooves (101) are formed on the right side of the external thread structure. Two sets of second sealing elements (11) are respectively arranged in the two sets of first sealing installation grooves (101).

3. The dissolvable key-opening multi-stage fracturing sleeve of claim 2, wherein, A through liquid hole (102) is formed in the middle part of the left end of the upper joint (1). When the core sleeve (2) is located on the left side of the inner cavity of the upper joint (1), the through liquid hole (102) is sealed.

4. The dissolvable key-opening multi-stage fracturing sleeve of claim 3, wherein, The inner hole of the lower joint (7) is arranged as a double-step structure. A limiting groove (702) is arranged on the right side of the inner hole of the lower joint (7). A plurality of sets of pin thread holes (701) are evenly formed on the left end of the lower joint (7) in a circumferential direction. The left end opening of the lower joint (7) is arranged as an internal thread structure. The right end outer surface of the lower joint (7) is arranged as an external thread structure.

5. The dissolvable key-opening multi-stage fracturing sleeve of claim 4, wherein, Four sets of second sealing installation grooves (201) are arranged on the left end of the core sleeve (2). Four sets of first sealing elements (8) are respectively arranged in the four sets of second sealing installation grooves (201). A plurality of sets of countersunk long hole (202) are arranged on the middle part of the core sleeve (2). The locking block (4) is arranged in the countersunk long hole (202).

6. The dissolvable key-opening multi-stage fracturing sleeve of claim 5, wherein, A plurality of sets of shear pin thread holes (203) and a blocking ring groove (204) are arranged on the right end of the core sleeve (2). The blocking ring groove (204) is located on the right side of the shear pin thread hole (203). An elastic blocking ring (13) is arranged in the blocking ring groove (204).

7. The dissolvable key-opening multi-stage fracturing sleeve of claim 6, wherein, Two sets of elastic sheet grooves (401) are arranged on the outer surface of the locking block (4). Two sets of elastic sheets (5) are respectively arranged in the two sets of elastic sheet grooves (401). Two sets of tooth grooves (402) are arranged on the right side of the inner wall of the locking block (4).

8. The dissolvable key-opening multi-stage fracturing sleeve of claim 7, wherein, The outer surface of the soluble key (3) is provided with a sealing groove (301) at both ends, the inner side of the sealing groove (301) is provided with a V-shaped seal (9) in the middle, the middle of the soluble key (3) is provided with two groups of lock teeth (302), wherein when the soluble key (3) is installed into the core sleeve (2), the two groups of lock teeth (302) are engaged with the two groups of tooth grooves (402).

9. The dissolvable key-opening multi-stage fracturing sleeve of claim 8, wherein, The left end surface of the blocking sleeve (6) is provided with a locking groove (601); When the blocking sleeve (6) is installed at the right end of the core sleeve (2), the locking groove (601) is located inside the cutting nail threaded hole (203) at this time, and is in an overlapping mode, and the cutting nail (12) is inserted into the locking groove (601) by passing through the cutting nail threaded hole (203), so that the connection of the core sleeve (2) and the blocking sleeve (6) is locked.

10. The dissolvable key-opening multi-stage fracturing sleeve of claim 9, wherein, The main bodies of the first sealing element (8) and the second sealing element (11) are both sealing rings, and the sealing ring stop ring is arranged at both ends of the sealing ring.

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