Drilling-free grading hoop capable of coring

Abstract

The invention discloses a coring drilling-free classification hoop, which belongs to the technical field of well cementation, and comprises a separation sleeve, a packing sealing structure, an upper joint, a circulating sleeve, a centralizing short section, a leather cup sealing structure and a lower joint, the upper connector, the circulating sleeve, the centralizing short section, the packing cup sealing structure, the packing sealing structure and the lower connector are sequentially distributed from top to bottom. Leather cup sealing structures are mounted on the outer side of the short central pipe and the outer side of the lower end of the centralizing short section; the lower end of the short central pipe is fixedly connected with the upper end of the packing sealing structure; the lower end of the packing sealing structure is fixedly connected with the upper end of the lower joint; an opening and closing assembly is arranged between the circulating sleeve and the neck bush; separable separating sleeves are installed in the upper connector, the circulating sleeve, the centralizing short section and the leather cup sealing structure. By means of the mode, pressing setting is conducted through the packing sealing structure and the leather cup sealing structure, pressing continues, and the opening and closing assembly between the circulating sleeve and the neck bush is opened; and after well cementation is completed, the separation sleeve is taken out through a fishing spear.

Description

Technical Field

[0001] The invention relates to the technical field of well cementing, and in particular to a coring and drilling-free grading collar. Background Art

[0002] Before drilling through the oil layer, the oil, gas and water are isolated by the formation. Therefore, it is necessary to lower the oil layer casing and inject cement before drilling through to isolate the oil, gas and water layers and prevent the oil, gas and water layers from being connected as one.

[0003] For example, Chinese patent CN216517920U discloses a cementing device, which is provided with a sleeve structure and a detachably connected cannula switch tool; through the cannula switch tool and the cementing sleeve structure, after cementing is completed, the cannula switch tool is lifted up to separate the cannula switch tool from the sleeve.

[0004] However, some oil and gas wells have high pressure and temperature and small annular space, which makes it difficult to recover the drill plug and inner liner during the cementing process.

[0005] Based on this, the present invention designs a coring and drilling-free grading collar to solve the above problems. Summary of the invention

[0006] In view of the above-mentioned shortcomings of the prior art, the present invention provides a coring and drilling-free grading collar.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: A coring and drilling-free grading collar comprises a separation sleeve, a sealing structure for isolation, an upper joint, a circulation sleeve, a straightening nipple, a leather cup sealing structure and a lower joint; The upper joint, the circulation sleeve, the righting nipple, the leather cup sealing structure, the packing sealing structure and the lower joint are arranged in sequence from top to bottom; The outer side of the lower end of the upper joint is fixedly connected to the upper end of the circulation sleeve, and the inner side of the lower end of the upper joint is fixedly connected to the upper end of the inner sleeve; the lower end of the circulation sleeve is fixedly connected to the outer side of the upper end of the righting pup joint, and the lower end of the inner sleeve is fixedly connected to the inner side of the upper end of the righting pup joint; the inner side of the lower end of the righting pup joint is fixedly connected to the upper end of the short center pipe; the outer side of the short center pipe and the outer side of the lower end of the righting pup joint are equipped with a leather cup sealing structure; the lower end of the short center pipe is fixedly connected to the upper end of the isolation sealing structure, and the lower end of the isolation sealing structure is fixedly connected to the upper end of the lower joint; An opening and closing assembly is arranged between the circulation sleeve and the inner liner; a cementing hole connected to the opening and closing assembly is opened on the upper side of the separation sleeve; a liquid inlet hole is arranged on the short central pipe and the isolation sealing structure; A detachable separation sleeve is installed inside the upper joint, circulation sleeve, straightening nipple and leather cup sealing structure; an upper plugging assembly is installed on the upper side of the separation sleeve, and a lower valve body assembly is installed on the lower side of the separation sleeve.

[0008] Furthermore, the separation sleeve is fixedly connected to the inner sleeve by shear nails; sealing rings are arranged on the outer sides of the upper and lower ends of the separation sleeve.

[0009] Furthermore, the upper sealing assembly includes a plug seat, a clamp and an upper limit sleeve. The upper limit sleeve is fixedly installed on the inner side of the separation sleeve through a locking block. The plug seat is fixedly installed on the inner side of the upper limit sleeve. A clamp that is clamped with the separation sleeve is fixedly installed between the upper limit sleeve and the plug seat.

[0010] Furthermore, the upper plugging assembly also includes a rubber plug, which is clamped with the rubber plug seat.

[0011] Furthermore, the lower valve body assembly includes a lower limit sleeve, a valve seat, a valve core, a self-priming valve pressure cap and a spring. The lower limit sleeve is fixedly installed on the inner side of the separation sleeve through a locking block. The valve seat is fixedly installed on the inner side of the lower limit sleeve. The self-priming valve pressure cap is fixedly installed on the inner side of the lower limit sleeve. The self-priming valve pressure cap is located on the upper side of the valve seat; the inner side of the self-priming valve pressure cap is fixedly connected to one end of the spring, and the other end of the spring is fixedly connected to the valve core.

[0012] Furthermore, the opening and closing assembly includes an opening sleeve, a closing sleeve, an inner circulation hole, a circulation hole, an upper locking ring and a locking ring cap; the opening sleeve and the closing sleeve are slidingly installed between the circulation sleeve and the inner sleeve; the closing sleeve is located on the upper side of the opening sleeve, and the upper locking ring is fixedly installed on the upper end of the closing sleeve through the locking ring cap; the circulation sleeve is provided with a circulation hole, and the inner sleeve is provided with an inner circulation hole; in the initial state, the opening sleeve is blocked between the inner circulation hole and the circulation hole, and the cementing hole is aligned with the inner circulation hole.

[0013] Furthermore, the leather cup sealing structure includes a leather cup cylinder, a leather cup piston, a leather cup cone sleeve and a leather cup. The upper end of the leather cup cylinder is fixedly mounted on the outer side of the lower end of the straightening short section. The leather cup piston slides within a limited position between the short center tube and the leather cup cylinder. The lower end of the leather cup piston is fixedly mounted with a leather cup cone sleeve for opening the leather cup through a lower locking ring. The leather cup is fixedly mounted on the lower side of the short center tube.

[0014] Furthermore, the isolation sealing structure includes a long hydraulic cylinder, a packer base pipe, a lower connecting sleeve and a sealing assembly, the upper end of the long hydraulic cylinder is fixedly installed on the outer side of the lower end of the short center pipe, and the upper end of the lower connecting sleeve is fixedly installed on the inner side of the lower end of the short center pipe; the inner side of the lower end of the lower connecting sleeve is fixedly connected to the upper end of the packer base pipe; a sleeve is provided on the upper side of the packer base pipe; the lower end of the packer base pipe is fixedly connected to the inner side of the upper end of the lower joint; the piston slides within a limited position on the outer side of the packer base pipe; and a liquid inlet hole is opened on the packer base pipe.

[0015] Furthermore, the sealing assembly includes a shear pin sleeve, a main rubber cylinder and a packer force transmission sleeve. The packer force transmission sleeve slides between the packer base pipe and the long hydraulic cylinder, and the upper end of the packer force transmission sleeve is fixedly connected to the piston; a limit ring for limiting is fixedly installed on the outer side of the lower end of the packer force transmission sleeve; the middle part of the shear pin sleeve is fixedly installed on the outer side of the packer base pipe through shear pins, and a base pipe locking ring is fixedly installed on the inner side of the lower end of the shear pin sleeve; the upper end of the shear pin sleeve is fixedly connected to the lower end of the packer force transmission sleeve, and the lower end of the shear pin sleeve is fixedly connected to the upper end of the main rubber cylinder through the upper rubber cylinder pressure cap; the lower end of the main rubber cylinder is fixedly connected to the outer side of the upper end of the lower joint through the lower rubber cylinder pressure cap.

[0016] Furthermore, a coring and drilling-free grading collar is also provided with a fishing spear for fishing out the separation sleeve; the fishing spear is threadedly connected to the upper end of the separation sleeve.

[0017] Compared with the prior art, the present invention has the following beneficial effects: the separation sleeve is located inside the upper joint, the circulation sleeve, the straightening short joint and the leather cup sealing structure; the upper joint, the circulation sleeve, the straightening short joint, the leather cup sealing structure, the isolation sealing structure and the lower joint are put into the well, so that the upper joint, the circulation sleeve, the straightening short joint, the leather cup sealing structure, the isolation sealing structure and the lower joint are arranged in order from top to bottom; the lower joint contacts the oil layer, and the upper joint is connected to the outside; then, the isolation sealing structure and the leather cup sealing structure are used to pressurize and seal, and the cementing tool is fixed to the inner side of the well wall through the isolation sealing structure and the leather cup sealing structure; and then the sealing structure and the leather cup sealing structure are used to seal. The pressure is applied to open the opening and closing assembly between the circulation sleeve and the inner sleeve, and the opening and closing assembly is now connected to the cementing hole; cementing fluid is injected through the cementing hole to perform cementing; during this process, the lower valve body assembly in the separation sleeve is used to prevent oil and gas from surging up, and at the same time, the cementing fluid is prevented from falling and causing pollution; after cementing is completed, the upper end of the separation sleeve is closed by the upper plugging assembly, and pressure is continued to be applied to move the separation sleeve downward, and at the same time, pressure is continued to be applied to close the opening and closing assembly to prevent cementing fluid from overflowing; the separation sleeve is then taken out by a spear; thereby cementing is achieved, and there is no need to drill plugs during the entire process, and the separation sleeve can be directly recovered after cementing is completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 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 prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 The structure of a core-removable, drill-free grading collar of the present invention is schematically shown. Figure 1 ; Figure 2 A schematic diagram of a fishing spear and its connection structure; Figure 3The structure of a core-removable, drill-free grading collar of the present invention is schematically shown. Figure 2 ; Figure 4 It is a schematic diagram of the circulation sleeve and its connection structure; Figure 5 It is a schematic diagram of the leather cup and its connection structure; Figure 6 It is a schematic diagram of a long hydraulic cylinder and its connection structure; Figure 7 Schematic diagram of the main rubber cylinder and its connection structure.

[0020] The numbers in the figure represent: 10. Shear pins; 1. Separation sleeve; 111. Rubber plug seat; 112. Stuck; 113. Upper limit sleeve; 114. Rubber plug; 121. Lower limit sleeve; 122. Valve seat; 123. Valve core; 124. Self-priming valve cap; 125. Spring; 13. Lock block; 14. Sealing ring; 15. Cementing hole; 2. Packing sealing structure; 21. Long hydraulic cylinder; 211. Piston; 22. Packer base pipe; 223. Bushing; 23. Shear pin sleeve; 232. Base pipe locking ring; 24. Main rubber cylinder; 241. Upper rubber cylinder cap; 242. Lower rubber cylinder pressure cap; 25. Lower connecting sleeve; 26. Packer force transmission sleeve; 261. Limiting ring; 3. Upper joint; 4. Circulation sleeve; 41. Inner liner; 411. Inner circulation hole; 412. Circulation hole; 42. Opening sleeve; 43. Closing sleeve; 431. Upper locking ring; 432. Locking ring cap; 5. Righting pup joint; 51. Short center pipe; 6. Leather cup sealing structure; 61. Leather cup hydraulic cylinder; 62. Leather cup piston; 63. Leather cup cone sleeve; 631. Lower locking ring; 64. Leather cup; 7. Lower joint; 8. Spear. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Embodiment 1: In some embodiments, please refer to the drawings of the specification Figure 1-Figure 6 , a coring and drilling-free grading collar, comprising a separation sleeve 1, a sealing structure 2, an upper joint 3, a circulation sleeve 4, a straightening nipple 5, a leather cup sealing structure 6 and a lower joint 7; The upper joint 3, the circulation sleeve 4, the straightening nipple 5, the leather cup sealing structure 6, the packing sealing structure 2 and the lower joint 7 are arranged in sequence from top to bottom; The outer side of the lower end of the upper joint 3 is fixedly connected to the upper end of the circulation sleeve 4, and the inner side of the lower end of the upper joint 3 is fixedly connected to the upper end of the inner sleeve 41; the lower end of the circulation sleeve 4 is fixedly connected to the outer side of the upper end of the righting pup joint 5, and the lower end of the inner sleeve 41 is fixedly connected to the inner side of the upper end of the righting pup joint 5; the inner side of the lower end of the righting pup joint 5 is fixedly connected to the upper end of the short center tube 51; the outer side of the short center tube 51 and the outer side of the lower end of the righting pup joint 5 are installed with a leather cup sealing structure 6; the lower end of the short center tube 51 is fixedly connected to the upper end of the isolation sealing structure 2, and the lower end of the isolation sealing structure 2 is fixedly connected to the upper end of the lower joint 7; An opening and closing assembly is provided between the circulation sleeve 4 and the inner liner 41; a cementing hole 15 connected to the opening and closing assembly is provided on the upper side of the separation sleeve 1; a liquid inlet hole is provided on the short central pipe 51 and the isolation sealing structure 2; A detachable separation sleeve 1 is installed inside the upper joint 3, the circulation sleeve 4, the straightening nipple 5 and the leather cup sealing structure 6; an upper plugging assembly is installed on the upper side of the separation sleeve 1, and a lower valve body assembly is installed on the lower side of the separation sleeve 1.

[0023] The separation sleeve 1 is fixedly connected to the inner liner sleeve 41 through shear nails 10 ; sealing rings 14 are provided on the outer sides of the upper and lower ends of the separation sleeve 1 .

[0024] In this embodiment, when the coring and drilling-free grading collar is working normally, the separation sleeve 1 is located inside the upper joint 3, the circulation sleeve 4, the straightening short joint 5 and the leather cup sealing structure 6, and the upper joint 3, the circulation sleeve 4, the straightening short joint 5, the leather cup sealing structure 6, the isolation sealing structure 2 and the lower joint 7 are put into the well, so that the upper joint 3, the circulation sleeve 4, the straightening short joint 5, the leather cup sealing structure 6, the isolation sealing structure 2 and the lower joint 7 are arranged in order from top to bottom; the lower joint 7 is in contact with the oil layer, and the upper joint 3 is connected to the outside; then, the isolation sealing structure 2 and the leather cup sealing structure 6 are pressurized and sealed, and the cementing tool is fixed by the isolation sealing structure 2 and the leather cup sealing structure 6 On the inner side of the well wall; continue to pressurize to open the opening and closing assembly between the circulation sleeve 4 and the inner liner sleeve 41, and at this time the opening and closing assembly is connected to the cementing hole 15; fill the cementing fluid through the cementing hole 15 to perform cementing; in this process, the lower valve body assembly in the separation sleeve 1 is used to prevent oil and gas from surging up, and at the same time, to prevent the cementing fluid from falling and causing pollution; after cementing is completed, the upper end of the separation sleeve 1 is closed by the upper plugging assembly, and the separation sleeve 1 is continuously pressurized to move downward, and at the same time, the opening and closing assembly is continuously pressurized to close to prevent the cementing fluid from overflowing; the separation sleeve 1 is then taken out by the spear 8; thereby cementing is achieved, and there is no need to drill plugs during the entire process, and the separation sleeve 1 can be directly recovered after cementing is completed.

[0025] Embodiment 2: In some embodiments, Figure 1-Figure 7As shown, as a preferred embodiment of the present invention, the upper plugging assembly includes a plug seat 111, a clamp 112 and an upper limit sleeve 113, the upper limit sleeve 113 is fixedly installed on the inner side of the separation sleeve 1 through a locking block 13, the plug seat 111 is fixedly installed on the inner side of the upper limit sleeve 113, and the clamp 112 that is clamped with the separation sleeve 1 is fixedly installed between the upper limit sleeve 113 and the plug seat 111; The upper plugging assembly also includes a rubber plug 114, which is clamped with the rubber plug seat 111; The lower valve body assembly includes a lower limit sleeve 121, a valve seat 122, a valve core 123, a self-priming valve pressure cap 124 and a spring 125. The lower limit sleeve 121 is fixedly installed on the inner side of the separation sleeve 1 through a locking block 13. The valve seat 122 is fixedly installed on the inner side of the lower limit sleeve 121. The self-priming valve pressure cap 124 is fixedly installed on the inner side of the lower limit sleeve 121. The self-priming valve pressure cap 124 is located on the upper side of the valve seat 122; the inner side of the self-priming valve pressure cap 124 is fixedly connected to one end of the spring 125, and the other end of the spring 125 is fixedly connected to the valve core 123; The opening and closing assembly comprises an opening sleeve 42, a closing sleeve 43, an inner circulation hole 411, a circulation hole 412, an upper locking ring 431 and a locking ring cap 432. The opening sleeve 42 and the closing sleeve 43 are installed between the circulation sleeve 4 and the inner liner sleeve 41 in a limited sliding manner; the closing sleeve 43 is located on the upper side of the opening sleeve 42, and the upper end of the closing sleeve 43 is fixedly installed with the upper locking ring 431 through the locking ring cap 432; the circulation sleeve 4 is provided with a circulation hole 412, and the inner liner sleeve 41 is provided with an inner circulation hole 411; in the initial state, the opening sleeve 42 is blocked between the inner circulation hole 411 and the circulation hole 412, and the cementing hole 15 is aligned with the inner circulation hole 411; The leather cup sealing structure 6 includes a leather cup cylinder 61, a leather cup piston 62, a leather cup cone sleeve 63 and a leather cup 64. The upper end of the leather cup cylinder 61 is fixedly installed on the outer side of the lower end of the straightening short section 5. The leather cup piston 62 slides between the short center tube 51 and the leather cup cylinder 61. The lower end of the leather cup piston 62 is fixedly installed with a leather cup cone sleeve 63 for opening the leather cup 64 through a lower locking ring 631. The leather cup 64 is fixedly installed on the lower side of the short center tube 51. The isolation sealing structure 2 comprises a long hydraulic cylinder 21, a packer base pipe 22, a lower connecting sleeve 25 and a sealing assembly. The upper end of the long hydraulic cylinder 21 is fixedly mounted on the outer side of the lower end of the short central pipe 51, and the upper end of the lower connecting sleeve 25 is fixedly mounted on the inner side of the lower end of the short central pipe 51; the inner side of the lower end of the lower connecting sleeve 25 is fixedly connected to the upper end of the packer base pipe 22; a bushing 223 is arranged on the upper side of the packer base pipe 22; the lower end of the packer base pipe 22 is fixedly connected to the inner side of the upper end of the lower joint 7; the piston 211 slides on the outer side of the packer base pipe 22; and a liquid inlet hole is provided on the packer base pipe 22; The sealing assembly includes a shearing nail sleeve 23, a main rubber cylinder 24 and a packer force transmission sleeve 26. The packer force transmission sleeve 26 slides between the packer base pipe 22 and the long hydraulic cylinder 21, and the upper end of the packer force transmission sleeve 26 is fixedly connected to the piston 211; a limiting ring 261 for limiting is fixedly installed on the outer side of the lower end of the packer force transmission sleeve 26; the middle part of the shearing nail sleeve 23 is fixedly installed on the outer side of the packer base pipe 22 through the shear nail 10, and a base pipe locking ring 232 is fixedly installed on the inner side of the lower end of the shearing nail sleeve 23; the upper end of the shearing nail sleeve 23 is fixedly connected to the lower end of the packer force transmission sleeve 26, and the lower end of the shearing nail sleeve 23 is fixedly connected to the upper end of the main rubber cylinder 24 through the upper rubber cylinder pressure cap 241; the lower end of the main rubber cylinder 24 is fixedly connected to the outer side of the upper end of the lower joint 7 through the lower rubber cylinder pressure cap 242.

[0026] The core-removable and drill-free grading collar is also provided with a fishing spear 8 for fishing out the separation sleeve 1 ; the fishing spear 8 is threadedly connected to the upper end of the separation sleeve 1 .

[0027] In this embodiment, the separation sleeve 1 is located inside the upper joint 3, the circulation sleeve 4, the straightening short section 5 and the leather cup sealing structure 6. The separation sleeve 1 is kept stable by the shear nails 10, and the shear nails 10 are broken by pressurizing during the recovery stage to achieve the recovery of the separation sleeve 1; the upper joint 3, the circulation sleeve 4, the straightening short section 5, the leather cup sealing structure 6, the isolation sealing structure 2 and the lower joint 7 are put into the well; the liquid flows into the space between the isolation base pipe 22 and the piston 211 through the liquid inlet hole on the isolation base pipe 22 The piston 211 is pushed to move vertically, the piston 211 pushes the packer force transmission sleeve 26 to move vertically, the packer force transmission sleeve 26 pushes the shear nail sleeve 23 to disconnect the shear nail 10 on the shear nail sleeve 23, the packer force transmission sleeve 26 continues to push the shear nail sleeve 23 to move, thereby pushing the main rubber cylinder 24 to move through the upper rubber cylinder pressure cap 241, the main rubber cylinder 24 is filled with liquid and expanded and fixed in the well; at the same time, the liquid flows into the short central tube 51 and the leather cup piston 62 through the liquid inlet hole on the short central tube 51, thereby The leather cup piston 62 is pushed to move, and the leather cup piston 62 pushes the leather cup 64 through the leather cup cone sleeve 63. The leather cup 64 expands and is fixed in the well due to the liquid, thereby completing the fixation of the cementing tool; then the wellhead pressure drives the opening sleeve 42 to slide downward, so that the opening sleeve 42 no longer blocks the inner circulation hole 411 and the circulation hole 412. At this time, the inner circulation hole 411, the circulation hole 412 and the cementing hole 15 are connected, and cementing fluid is injected through the cementing hole 15, the inner circulation hole 411 and the circulation hole 412 to perform cementing; cementing is completed After that, the rubber plug 114 is put in. After the rubber plug 114 hits the rubber plug seat 111 and the card 112, the pressure at the wellhead is continued to be maintained, so that the rubber plug 114 drives the separation sleeve 1 to move vertically downward through the rubber plug seat 111, the card 112 and the upper limit sleeve 113, until the cementing hole 15 and the inner circulation hole 411 are offset; the pressure is continued to be applied to make the closing sleeve 43 move vertically downward, and the closing sleeve 43 is blocked between the circulation hole 412 and the inner circulation hole 411 to prevent the cementing fluid from overflowing; then the separation sleeve 1 is salvaged out by the fishing spear 8.

[0028] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A coring and drilling-free grading collar, comprising a separation sleeve (1), a sealing structure (2), an upper joint (3), a circulation sleeve (4), a righting nipple (5), a leather cup sealing structure (6) and a lower joint (7), characterized in that: The upper joint (3), the circulation sleeve (4), the righting nipple (5), the leather cup sealing structure (6), the packing sealing structure (2) and the lower joint (7) are arranged in sequence from top to bottom; The outer side of the lower end of the upper joint (3) is fixedly connected to the upper end of the circulation sleeve (4), and the inner side of the lower end of the upper joint (3) is fixedly connected to the upper end of the inner sleeve (41); the lower end of the circulation sleeve (4) is fixedly connected to the outer side of the upper end of the righting pup joint (5), and the lower end of the inner sleeve (41) is fixedly connected to the inner side of the upper end of the righting pup joint (5); the inner side of the lower end of the righting pup joint (5) is fixedly connected to the upper end of the short center tube (51); a leather cup sealing structure (6) is installed on the outer side of the short center tube (51) and the outer side of the lower end of the righting pup joint (5); the lower end of the short center tube (51) is fixedly connected to the upper end of the isolation sealing structure (2), and the lower end of the isolation sealing structure (2) is fixedly connected to the upper end of the lower joint (7); An opening and closing assembly is provided between the circulation sleeve (4) and the inner liner sleeve (41); a cementing hole (15) communicating with the opening and closing assembly is provided on the upper side of the separation sleeve (1); and a liquid inlet hole is provided on the short central pipe (51) and the isolation sealing structure (2); A detachable separation sleeve (1) is installed inside the upper joint (3), the circulation sleeve (4), the straightening nipple (5) and the leather cup sealing structure (6); an upper plugging assembly is installed on the upper side of the separation sleeve (1), and a lower valve body assembly is installed on the lower side of the separation sleeve (1).

2. The corable and drill-free grading collar according to claim 1, characterized in that: The separation sleeve (1) is fixedly connected to the inner liner sleeve (41) via shear pins (10); sealing rings (14) are provided on the outer sides of both upper and lower ends of the separation sleeve (1).

3. The corable and drill-free grading collar according to claim 2, characterized in that: The upper plugging assembly comprises a rubber plug seat (111), a clamp (112) and an upper limit sleeve (113); the upper limit sleeve (113) is fixedly mounted on the inner side of the separation sleeve (1) via a locking block (13); the rubber plug seat (111) is fixedly mounted on the inner side of the upper limit sleeve (113); and the clamp (112) which is clamped with the separation sleeve (1) is fixedly mounted between the upper limit sleeve (113) and the rubber plug seat (111).

4. The corable and drill-free grading collar according to claim 3 is characterized in that: The upper plugging assembly also includes a rubber plug (114), and the rubber plug (114) is clamped with the rubber plug seat (111).

5. The core-removable, drill-free grading collar according to claim 4, characterized in that: The lower valve body assembly comprises a lower limit sleeve (121), a valve seat (122), a valve core (123), a self-priming valve pressure cap (124) and a spring (125); the lower limit sleeve (121) is fixedly mounted on the inner side of the separation sleeve (1) via a locking block (13); the valve seat (122) is fixedly mounted on the inner side of the lower limit sleeve (121); the self-priming valve pressure cap (124) is fixedly mounted on the inner side of the lower limit sleeve (121); the self-priming valve pressure cap (124) is located on the upper side of the valve seat (122); the inner side of the self-priming valve pressure cap (124) is fixedly connected to one end of the spring (125); and the other end of the spring (125) is fixedly connected to the valve core (123).

6. The core-recoverable, drill-free grading collar according to claim 5, characterized in that: The opening and closing assembly comprises an opening sleeve (42), a closing sleeve (43), an inner circulation hole (411), a circulation hole (412), an upper locking ring (431) and a locking ring cap (432); the opening sleeve (42) and the closing sleeve (43) are installed between the circulation sleeve (4) and the inner liner sleeve (41) in a limited sliding manner; the closing sleeve (43) is located on the upper side of the opening sleeve (42), and the upper end of the closing sleeve (43) is fixedly installed with the upper locking ring (431) through the locking ring cap (432); the circulation sleeve (4) is provided with a circulation hole (412), and the inner liner sleeve (41) is provided with an inner circulation hole (411); in an initial state, the opening sleeve (42) is blocked between the inner circulation hole (411) and the circulation hole (412), and the cementing hole (15) is aligned with the inner circulation hole (411).

7. The corable and drill-free grading collar according to claim 6, characterized in that: The leather cup sealing structure (6) comprises a leather cup cylinder (61), a leather cup piston (62), a leather cup cone sleeve (63) and a leather cup (64). The upper end of the leather cup cylinder (61) is fixedly mounted on the outer side of the lower end of the straightening short section (5). The leather cup piston (62) slides in a limited position between the short center tube (51) and the leather cup cylinder (61). The lower end of the leather cup piston (62) is fixedly mounted with a leather cup cone sleeve (63) for opening the leather cup (64) via a lower locking ring (631). The leather cup (64) is fixedly mounted on the lower side of the short center tube (51).

8. The core-removable, drill-free grading collar according to claim 7, characterized in that: The isolation sealing structure (2) comprises a long hydraulic cylinder (21), a packer base pipe (22), a lower connecting sleeve (25) and a sealing assembly, wherein the upper end of the long hydraulic cylinder (21) is fixedly mounted on the outer side of the lower end of the short central pipe (51), and the upper end of the lower connecting sleeve (25) is fixedly mounted on the inner side of the lower end of the short central pipe (51); the inner side of the lower end of the lower connecting sleeve (25) is fixedly connected to the upper end of the packer base pipe (22); a bushing (223) is provided on the upper side of the packer base pipe (22); the lower end of the packer base pipe (22) is fixedly connected to the inner side of the upper end of the lower joint (7); the piston (211) slides in a limited manner on the outer side of the packer base pipe (22); and a liquid inlet hole is provided on the packer base pipe (22).

9. The corable and drill-free grading collar according to claim 8, characterized in that: The sealing assembly comprises a shearing nail sleeve (23), a main rubber cylinder (24) and a packer force transmission sleeve (26); the packer force transmission sleeve (26) slides between the packer base pipe (22) and the long hydraulic cylinder (21); the upper end of the packer force transmission sleeve (26) is fixedly connected to the piston (211); a limiting ring (261) for limiting is fixedly installed on the outer side of the lower end of the packer force transmission sleeve (26); the middle part of the shearing nail sleeve (23) is connected by the shearing nail (10) The shear nail sleeve (23) is fixedly mounted on the outside of the packer base pipe (22), and a base pipe locking ring (232) is fixedly mounted on the inner side of the lower end of the shear nail sleeve (23); the upper end of the shear nail sleeve (23) is fixedly connected to the lower end of the packer force transmission sleeve (26), and the lower end of the shear nail sleeve (23) is fixedly connected to the upper end of the main rubber sleeve (24) through an upper rubber sleeve pressure cap (241); the lower end of the main rubber sleeve (24) is fixedly connected to the outer side of the upper end of the lower joint (7) through a lower rubber sleeve pressure cap (242).

10. The corable and drill-free grading collar according to claim 9, characterized in that: The core-removable, drill-free grading collar is also provided with a fishing spear (8) for fishing the separation sleeve (1); the fishing spear (8) is threadedly connected to the upper end of the separation sleeve (1).

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