Full-drillable deblocking packer with detachable safety connector, system and method
By designing a fully drillable and unsealable packer and special grinding and milling tool, the problem of long construction cycle and high cost when the packer cannot be unsealed is solved, and efficient grinding and milling is achieved, saving construction time and cost.
Patent Information
- Application Number
- CN202311096951.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-29
- Publication Date
- 2025-02-28
AI Technical Summary
In the existing oilfield water injection technology, when the packer cannot be unsealed, the construction period is long, the cost is high, and the grinding and milling work time is long, which is high.
A fully drillable and unsealed packer for disconnectable safety joints is designed, with upper gear ring, rubber cylinder, partition ring, lower gear ring, seat seal piston and well washing piston made of easy-to-mill materials, and is equipped with special grinding and milling tools to only mill parts on the outer side of the liner or center tube to achieve rapid unsealing.
It improves the grinding and milling efficiency of the packer, shortens the construction cycle, reduces costs, and saves secondary salvage construction, saving time and expenses.
Smart Images
Figure CN119531767A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of oilfield water injection, and in particular relates to a fully drillable packer with a detachable safety joint, a system and a method. Background Art
[0002] During the oil field development process, it is necessary to install packers underground to isolate the formation to ensure the smooth implementation of various processes.
[0003] In actual production, the packer installed underground for a long time will have corrosion and scaling problems, which may easily cause the packer to lose its function and the pipe string cannot be pulled out, that is, the packer cannot be unsealed. If the packer cannot be unsealed in the set way, then it is necessary to use overhaul and well repair equipment. This overhaul treatment method not only has a long construction period and high cost, but also seriously affects production operations.
[0004] In order to solve the above problems, technicians used a packer with a safety joint assembly at the upper end. When the packer in the well cannot be unsealed, the part above the safety joint can be detached from the packer body and lifted out of the well by pressing the tubing, lifting the tubing, rotating the tubing, etc., and then the milling tool is lowered to mill the packer body to unseal it. However, the milling workload of the packer body in the prior art is very large, the milling time is very long, and the construction cost is still high. In addition, in the prior art, after the milling is completed, it is necessary to lower the salvage tool to remove the tubing that falls to the bottom of the well after unsealing, which further increases the construction cost. Summary of the invention
[0005] The present invention provides a fully drillable packer with a detachable safety joint, a system and a method, aiming to solve the problems of long construction period and high cost when the packer in the prior art cannot be unsealed by optimizing the prior art.
[0006] To achieve the above object, the technical solution adopted by the present invention is: A fully drillable and unsealed packer with a detachable safety joint, comprising a packer body, a safety joint assembly and a joint connecting sleeve; the packer body comprises a center pipe, a liner, an upper retaining ring, a rubber tube, a spacer ring, a lower retaining ring, a setting piston and a well flushing piston; the liner is fixedly connected to the outside of the center pipe, and the outer wall of the liner is sequentially connected with an upper retaining ring, a plurality of rubber tubes and a lower retaining ring from top to bottom, and spacer rings are connected between adjacent rubber tubes; a well flushing piston is connected to the outer wall of the center pipe below the lower retaining ring; a setting piston is connected to the space enclosed by the lower retaining ring, the well flushing piston, the center pipe and the liner; the safety joint assembly is connected to the upper end of the center pipe via a joint connecting sleeve.
[0007] The upper retaining ring, the rubber cylinder, the spacer ring, the lower retaining ring, the setting piston and the well flushing piston are all made of easy-to-grind and mill materials.
[0008] The easy-to-grind and mill material is polyetheretherketone, non-metallic structural material or composite material.
[0009] The safety joint assembly comprises an upper connecting sleeve, a lower connecting sleeve, a piston sleeve, a sliding sleeve, a locking ball, a safety pin, a rotating pin and a slideway pin; the upper connecting sleeve is sleeved on the outer side wall of the joint connecting sleeve; the upper end of the lower connecting sleeve is connected to the inner side wall of the lower end of the upper connecting sleeve by a thread; the upper end of the piston sleeve is connected to the outer side wall of the lower end of the upper connecting sleeve by a thread; the sliding sleeve is sleeved on the outer side wall of the lower connecting sleeve and is placed in the annular space between the piston sleeve and the lower connecting sleeve, and the sliding sleeve is connected to the lower connecting sleeve by a safety pin; a through hole is provided on the side wall of the lower connecting sleeve, and a locking ball is placed in the through hole of the locking ball; a blind hole matching the through hole accommodating the locking ball is provided on the outer wall of the joint connecting sleeve, the locking ball extends into the blind hole, and the locking ball rests on the inner side wall of the sliding sleeve; A withdrawal hole for the locking ball to withdraw is also provided on the inner wall, and the withdrawal hole is located above the locking ball; a liquid hole is provided on the side wall of the lower connecting sleeve, and the liquid hole corresponds to the space above the sliding sleeve; the rotating pin is laterally installed on the lower connecting sleeve, and a blind hole is provided on the outer side of the joint connecting sleeve at a position corresponding to the rotating pin, and the end of the rotating pin is inserted into the blind hole; an L-shaped slide is provided on the outer side of the joint connecting sleeve, and the L-shaped slide is composed of a horizontal section and a vertical section; the slide pin is laterally installed on the lower connecting sleeve, and the end of the slide pin is inserted in the horizontal section of the L-shaped slide to prevent the joint connecting sleeve from axially disengaging from the center tube.
[0010] The joint connecting sleeve is a hollow cylindrical structure, and its lower outer diameter is larger than the upper outer diameter; an annular protrusion is arranged on the lower outer wall of the joint connecting sleeve, and two groups of horizontally arranged blind holes are opened on the upper and lower outer walls above the annular protrusion, and multiple blind holes in each group are arranged in a circular matrix.
[0011] A detachable safety joint fully drillable unsealing system comprises at least a detachable safety joint fully drillable unsealing packer and a milling tool; the milling tool is used for milling parts outside a liner or a central pipe.
[0012] The milling tool comprises an upper joint, a knife barrel, a cylindrical cutter head and a salvage spear matching the inner diameter of the center pipe; a connecting pipe is arranged at the upper part of the upper joint; the upper end of the knife barrel is connected to the lower end of the upper joint; the upper end of the salvage spear is detachably connected to the lower end of the connecting pipe; the cylindrical cutter head is connected to the lower end of the knife barrel, and the lower end of the salvage spear extends out of the cylindrical cutter head; an annular space is arranged between the knife barrel and the salvage spear, and between the cylindrical cutter head and the salvage spear; an axial through hole is axially arranged at the connection between the connecting pipe and the inner wall of the upper joint, and the axial through hole connects the annular space with the internal space of the oil pipe string.
[0013] There is a gap between the lower outer wall of the connecting pipe and the inner wall of the upper joint; a through hole for connecting with a salvage spear is opened on the side wall of the lower end of the connecting pipe; radial through holes are opened at positions corresponding to the lower end of the knife barrel and the connecting pipe.
[0014] A method for unsealing a detachable safety joint fully drillable unsealing system, using a detachable safety joint fully drillable unsealing system, comprising the following steps: Step 1: lower the fully drillable packer with detachable safety joint into the predetermined position underground to complete the installation of the packer; Step 2: When the fully drillable packer with detachable safety joint fails to be unsealed, pressurize the pipe string. The pressure reaches the upper side of the sliding sleeve through the fluid hole and pushes the sliding sleeve to cut off the safety pin. Step 3: The sliding sleeve slides downward. When the retreat hole on the sliding sleeve is aligned with the locking ball, the locking ball comes out of the blind hole outside the joint sleeve, so that the locking effect of the locking ball is released. At this time, the lower connecting sleeve can rotate relative to the joint connecting sleeve; Step 4: The rotating pin is cut off and the lower connecting sleeve is rotated, so that the slideway pin installed on the lower connecting sleeve slides out from the L-shaped slideway, thereby separating the safety joint assembly from the detachable safety joint fully drillable unsealing packer body; Step 5: Lift the safety joint assembly and the tubing string above it out of the well; Step 6: The milling tool is lowered into the well through the tubing string. The fishing spear in the milling tool clamps the center pipe. The cylindrical cutter head on the milling tool is driven to rotate by rotating the tubing string to mill the parts outside the liner or center pipe to achieve unsealing.
[0015] Beneficial effects: 1. The upper retaining ring, rubber cylinder, spacer ring, lower retaining ring, setting piston and well flushing piston in the present invention are all made of easy-to-grind materials, and the grinding efficiency is greatly improved compared with the prior art.
[0016] 2. The present invention designs a special milling tool, which only mills the parts outside the liner or the center tube, without milling the liner and the center tube, thereby further improving the milling efficiency.
[0017] 3. After the milling and unsealing of the present invention, the salvage spear in the milling tool can clamp the central pipe and then lift it out of the well. That is to say, after milling, the pipe string below the packer will not fall to the bottom of the well, eliminating the need for secondary salvage construction, saving construction time and cost.
[0018] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] 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 will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0020] Figure 1 It is a schematic diagram of the connection structure between the safety joint assembly and the packer body in the well completion state of the present invention.
[0021] Figure 2 It is a structural schematic diagram of the grinding and milling tool of the present invention.
[0022] Figure 3 It is a structural schematic diagram of the safety joint assembly of the present invention.
[0023] Figure 4 It is an axial cross-sectional view of the joint connecting sleeve of the present invention.
[0024] Figure 5 It is a planar development diagram of the outer circumference of the joint connecting sleeve of the present invention.
[0025] Figure 6 It is a schematic diagram of the connection structure between the joint connecting sleeve and the packer body of the present invention.
[0026] Figure 7 It is a schematic diagram of the connection structure between the milling tool and the packer body of the present invention.
[0027] In the figure: 1, upper connecting sleeve; 2, joint connecting sleeve; 3, piston sleeve; 4, sliding sleeve; 5, lower connecting sleeve; 6, center pipe; 7, upper retaining ring; 8, L-shaped slideway; 9, rubber cylinder; 10, spacer ring; 11, liner; 12, lower retaining ring; 13, setting piston; 14, well washing piston; 15, retreat hole; 16, lock ball; 17, safety pin; 18, rotating pin; 19, slideway pin; 20, liquid hole; 21, upper joint; 22, knife barrel; 23, salvage spear; 24, cylindrical cutter head; 25, axial through hole; 26, radial through hole; 27, annular protrusion; 28, connecting pipe. DETAILED DESCRIPTION
[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.
[0029] Embodiment 1: according to Figure 1-Figure 7 The illustrated embodiment shows a fully drillable and unsealed packer with a detachable safety joint, comprising a packer body, a safety joint assembly and a joint connecting sleeve 2; the packer body comprises a center pipe 6, a liner 11, an upper retaining ring 7, a rubber tube 9, a spacer ring 10, a lower retaining ring 12, a setting piston 13 and a well flushing piston 14; the liner 11 is fixedly connected to the outside of the center pipe 6, the outer side wall of the liner 11 is sequentially connected with an upper retaining ring 7, a plurality of rubber tubes 9 and a lower retaining ring 12 from top to bottom, and a spacer ring 10 is connected between adjacent rubber tubes 9; a well flushing piston 14 is connected to the outer side wall of the center pipe 6 below the lower retaining ring 12; a setting piston 13 is connected to the space enclosed by the lower retaining ring 12, the well flushing piston 14, the center pipe 6 and the liner 11; the safety joint assembly is connected to the upper end of the center pipe 6 via the joint connecting sleeve 2.
[0030] In actual use, the fully drillable packer with detachable safety joint is lowered into the predetermined position in the well through the oil pipe string to complete the installation of the packer. When the packer cannot be released normally, the safety joint assembly is separated from the packer body by conventional means such as pressing the central pipe 6, lifting the central pipe 6 or rotating the central pipe 6, and the safety joint assembly and the oil pipe string above it are lifted out of the well. Then, the oil pipe string is lowered into the wellbore. Figure 2 The special milling tool shown in the figure drives the cutter head on the milling tool to rotate by rotating the oil pipe string, thereby achieving the milling of the upper retaining ring 7, the rubber cylinder 9, the spacer ring 10, the lower retaining ring 12, the setting piston 13 and the well washing piston 14. After the milling is completed, the packer body with a falling tendency is stuck by the milling tool, and then the packer body is lifted out of the well.
[0031] When the packer cannot be unsealed normally, the present invention can separate the safety joint assembly from the packer body, and when the milling tool is lowered for milling, only the parts outside the liner 11 or the center pipe 6 are milled, and the liner 11 and the center pipe 6 do not need to be milled, thereby further improving the efficiency of milling. After milling and unsealing, the milling tool can clamp the center pipe 6 and then lift it out of the well. That is to say, after milling, the pipe string below the packer will not fall to the bottom of the well, eliminating the need for secondary salvage construction, saving construction time and cost.
[0032] Embodiment 2: according to Figure 1 The illustrated detachable safety joint fully drillable packer is different from the first embodiment in that the upper retaining ring 7, rubber cylinder 9, spacer ring 10, lower retaining ring 12, setting piston 13 and well flushing piston 14 are all made of easy-to-grind materials.
[0033] Furthermore, the easy-to-grind and mill material is polyetheretherketone, non-metallic structural material or composite material.
[0034] In actual use, the upper retaining ring 7, the rubber cylinder 9, the spacer ring 10, the lower retaining ring 12, the setting piston 13 and the well flushing piston 14 are all made of easy-to-grind materials, so that they can be easily milled off when using a milling tool to mill them, thereby easily unblocking the packer, with outstanding effect.
[0035] Embodiment three: according to Figure 1 and Figure 3 The illustrated detachable safety joint fully drillable packer is different from the first embodiment in that: the safety joint assembly comprises an upper connecting sleeve 1, a lower connecting sleeve 5, a piston sleeve 3, a sliding sleeve 4, a locking ball 16, a safety pin 17, a rotating pin 18 and a slideway pin 19; The upper connecting sleeve 1 is sleeved on the outer wall of the joint connecting sleeve 2; the upper end of the lower connecting sleeve 5 is connected to the inner side wall of the lower end of the upper connecting sleeve 1 by threading; the upper end of the piston sleeve 3 is connected to the outer side wall of the lower end of the upper connecting sleeve 1 by threading; the sliding sleeve 4 is sleeved on the outer side wall of the lower connecting sleeve 5, and is placed in the annular space between the piston sleeve 3 and the lower connecting sleeve 5, and the sliding sleeve 4 is connected to the lower connecting sleeve 5 by a safety pin 17; a through hole is provided on the side wall of the lower connecting sleeve 5, and a locking ball 16 is placed in the through hole of the locking ball; a blind hole matching the through hole for accommodating the locking ball 16 is provided on the outer wall of the joint connecting sleeve 2, and the locking ball 16 extends into the blind hole, and the locking ball 16 rests on the inner side wall of the sliding sleeve 4; the inner wall of the sliding sleeve 4 is also A withdrawal hole 15 is provided for the locking ball 16 to withdraw, and the withdrawal hole 15 is located above the locking ball 16; a liquid hole 20 is provided on the side wall of the lower connecting sleeve 5, and the liquid hole 20 corresponds to the space above the sliding sleeve 4; the rotating pin 18 is laterally installed on the lower connecting sleeve 5, and a blind hole is provided on the outer side of the joint connecting sleeve 2 at a position corresponding to the rotating pin 18, and the end of the rotating pin 18 is inserted into the blind hole; an L-shaped slide 8 is opened on the outer side of the joint connecting sleeve 2, and the L-shaped slide 8 is composed of a horizontal section and a vertical section; the slide pin 19 is laterally installed on the lower connecting sleeve 5, and the end of the slide pin 19 is inserted in the horizontal section of the L-shaped slide 8, which is used to prevent the joint connecting sleeve 2 from axially disengaging from the center pipe 6.
[0036] In actual use, when the fully drillable packer with detachable safety joint fails to be lifted and unsealed, pressure is applied to the pipe column, and the pressure reaches the upper side of the sliding sleeve 4 through the liquid hole 20 and pushes the sliding sleeve 4 to cut the safety pin 17; the sliding sleeve 4 slides downward, and when the retreat hole 15 on the sliding sleeve 4 is aligned with the locking ball 16, the locking ball 16 is disengaged from the blind hole on the outer side of the joint connecting sleeve 2, so that the locking effect of the locking ball 16 is released, and at this time, the lower connecting sleeve 5 can rotate relative to the joint connecting sleeve 2; the rotating pin 18 is cut off and the lower connecting sleeve is rotated The connecting sleeve 5 makes the slideway pin 19 installed on the lower connecting sleeve 5 slide out from the L-shaped slideway 8, so that the safety joint assembly is separated from the detachable safety joint fully drillable unsealing packer body; the safety joint assembly and the oil pipe string above it are lifted out of the well; the milling tool is lowered into the well through the oil pipe string, and the fishing spear 23 in the milling tool clamps the center pipe 6. The cylindrical cutter head 24 on the milling tool is driven to rotate by rotating the oil pipe string to mill the parts outside the liner 11 or the center pipe 6 to achieve unsealing.
[0037] Embodiment 4: according to Figure 1 , Figure 4 and Figure 6 The shown embodiment is a detachable safety joint fully drillable packer, which is different from the embodiment 1 in that: the joint connecting sleeve 2 is a hollow cylindrical structure, and its lower outer diameter is larger than the upper outer diameter; an annular protrusion 27 is provided on the lower outer wall of the joint connecting sleeve 2, and two groups of horizontally arranged blind holes are opened on the upper and lower outer walls above the annular protrusion 27, and a plurality of blind holes in each group are arranged in a circular matrix.
[0038] In actual use, the joint connecting sleeve 2 adopts the above technical solution to facilitate the realization of its connection function.
[0039] Embodiment five: Reference Figure 1-Figure 7 A detachable safety joint fully drillable unsealing system includes at least a detachable safety joint fully drillable unsealing packer and a milling tool; the milling tool is used to mill the parts on the outside of the liner 11 or the center pipe 6.
[0040] In actual use, when the fully drillable packer with detachable safety joint fails to be lifted and unsealed, pressure is applied to the pipe column, and the pressure reaches the upper side of the sliding sleeve 4 through the liquid hole 20 and pushes the sliding sleeve 4 to cut the safety pin 17; the sliding sleeve 4 slides downward, and when the retreat hole 15 on the sliding sleeve 4 is aligned with the locking ball 16, the locking ball 16 is disengaged from the blind hole on the outer side of the joint connecting sleeve 2, so that the locking effect of the locking ball 16 is released, and at this time, the lower connecting sleeve 5 can rotate relative to the joint connecting sleeve 2; the rotating pin 18 is cut off and the lower connecting sleeve is rotated The connecting sleeve 5 makes the slideway pin 19 installed on the lower connecting sleeve 5 slide out from the L-shaped slideway 8, so that the safety joint assembly is separated from the detachable safety joint fully drillable unsealing packer body; the safety joint assembly and the oil pipe string above it are lifted out of the well; the milling tool is lowered into the well through the oil pipe string, and the fishing spear 23 in the milling tool clamps the center pipe 6. The cylindrical cutter head 24 on the milling tool is driven to rotate by rotating the oil pipe string to mill the parts outside the liner 11 or the center pipe 6 to achieve unsealing.
[0041] Embodiment six: Reference Figure 2 and Figure 7 , a fully drillable unsealing system with a detachable safety joint, which is different from the fifth embodiment in that: the milling tool includes an upper joint 21, a knife barrel 22, a cylindrical cutter head 24 and a salvage spear 23 matching the inner diameter of the central pipe 6; a connecting pipe 28 is provided at the upper part of the upper joint 21; the upper end of the knife barrel 22 is connected to the lower end of the upper joint 21; the upper end of the salvage spear 23 is detachably connected to the lower end of the connecting pipe 28; the cylindrical cutter head 24 is connected to the lower end of the knife barrel 22, and the lower end of the salvage spear 23 extends out of the cylindrical cutter head 24; an annular space is provided between the knife barrel 22 and the salvage spear 23, and between the cylindrical cutter head 24 and the salvage spear 23; an axial through hole 25 is axially provided at the connection between the connecting pipe 28 and the inner wall of the upper joint 21, and the axial through hole 25 connects the annular space with the internal space of the oil pipe string.
[0042] In actual use, when the packer body fails to be lifted and unsealed, the safety joint assembly is separated from the packer body through operation, and the safety joint assembly and the oil pipe string above it are lifted out of the well; the milling tool is lowered into the well through the oil pipe string, and the salvage spear 23 in the milling tool clamps the center pipe 6. The cylindrical cutter head 24 on the milling tool is driven to rotate by rotating the oil pipe string to mill the parts on the outside of the liner 11 or the center pipe 6 to achieve unsealing.
[0043] The present invention designs a special milling tool, during which only the parts outside the liner 11 or the center tube 6 are milled, and the liner 11 and the center tube 6 are not milled, thereby further improving the milling efficiency.
[0044] The milling cutter head in this embodiment is a cylindrical cutter head 24, which can completely mill the parts outside the liner 11 or the center pipe 6 when it rotates.
[0045] Embodiment seven: Reference Figure 1 and Figure 7 , a detachable safety joint fully drillable unsealing system, which is different from the sixth embodiment in that: there is a gap between the lower outer wall of the connecting pipe 28 and the inner wall of the upper joint 21; a through hole for connecting with the salvage spear 23 is opened on the side wall of the lower end of the connecting pipe 28; a radial through hole 26 is opened at the position corresponding to the lower end of the knife barrel 22 and the connecting pipe 28.
[0046] In actual use, the salvage spear 23 and the connecting pipe 28 are connected and fixed by bolts through the through hole opened at the lower end of the connecting pipe 28. The provision of the radial through hole 26 plays a role in balancing the internal and external pressures.
[0047] Embodiment eight: Reference Figure 1-Figure 7 A method for unsealing a detachable safety joint fully drillable unsealing system, using a detachable safety joint fully drillable unsealing system, comprising the following steps: Step 1: lower the fully drillable packer with detachable safety joint into the predetermined position underground to complete the installation of the packer; Step 2: When the fully drillable packer with detachable safety joint fails to be lifted and unsealed, pressure is applied to the pipe string, and the pressure reaches the upper side of the sliding sleeve 4 through the liquid hole 20 and pushes the sliding sleeve 4 to cut off the safety pin 17; Step 3: The sliding sleeve 4 slides downward. When the retreat hole 15 on the sliding sleeve 4 is aligned with the locking ball 16, the locking ball 16 is released from the blind hole outside the joint connecting sleeve 2, so that the locking effect of the locking ball 16 is released. At this time, the lower connecting sleeve 5 can rotate relative to the joint connecting sleeve 2; Step 4: The rotating pin 18 is cut off and the lower connecting sleeve 5 is rotated, so that the slideway pin 19 installed on the lower connecting sleeve 5 slides out from the L-shaped slideway 8, thereby separating the safety joint assembly from the detachable safety joint fully drillable unsealing packer body; Step 5: Lift the safety joint assembly and the tubing string above it out of the well; Step 6: The milling tool is lowered into the well through the tubing string. The salvage spear 23 in the milling tool clamps the center pipe 6. The cylindrical cutter head 24 on the milling tool is driven to rotate by rotating the tubing string to mill the parts outside the liner 11 or the center pipe 6 to achieve unsealing.
[0048] After the milling and unsealing are implemented by the solution of the present invention, the fishing spear in the milling tool can clamp the central pipe and then lift it out of the well. That is to say, after milling, the pipe string below the packer will not fall to the bottom of the well, eliminating the need for secondary fishing construction, saving construction time and cost.
[0049] In the absence of conflicts, technicians in this field can combine the relevant technical features in the above examples according to actual conditions to achieve corresponding technical effects. The specific combinations are not described here one by one.
[0050] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.
[0051] In addition, the descriptions of "first", "second", etc. in the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.
[0052] The above are only preferred embodiments of the present invention. The present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein. Any simple modification, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.
Claims
1. A fully drillable packer with a detachable safety joint, characterized in that: The invention comprises a packer body, a safety joint assembly and a joint connection sleeve (2); the packer body comprises a center pipe (6), a liner (11), an upper retaining ring (7), a rubber tube (9), a spacer ring (10), a lower retaining ring (12), a setting piston (13) and a well-washing piston (14); the liner (11) is fixedly connected to the outside of the center pipe (6); the outer wall of the liner (11) is connected with an upper retaining ring (7), a plurality of rubber tubes (9) and a lower retaining ring (12) in sequence from top to bottom, and a spacer ring (10) is connected between adjacent rubber tubes (9); the outer wall of the center pipe (6) below the lower retaining ring (12) is connected with a well-washing piston (14); the setting piston (13) is connected in a space enclosed by the lower retaining ring (12), the well-washing piston (14), the center pipe (6) and the liner (11); the safety joint assembly is connected to the upper end of the center pipe (6) via the joint connection sleeve (2).
2. A fully drillable packer with a detachable safety joint as claimed in claim 1, characterized in that: The upper retaining ring (7), the rubber cylinder (9), the spacer ring (10), the lower retaining ring (12), the setting piston (13) and the well flushing piston (14) are all made of easy-to-grind and mill materials.
3. A fully drillable packer with a detachable safety joint as claimed in claim 1, characterized in that: The easy-to-grind and mill material is polyetheretherketone, non-metallic structural material or composite material.
4. A fully drillable packer with a detachable safety joint as claimed in claim 1, characterized in that: The safety joint assembly comprises an upper connecting sleeve (1), a lower connecting sleeve (5), a piston sleeve (3), a sliding sleeve (4), a locking ball (16), a safety pin (17), a rotating pin (18) and a slideway pin (19); The upper connecting sleeve (1) is sleeved on the outer wall of the joint connecting sleeve (2); the upper end of the lower connecting sleeve (5) is connected to the inner wall of the lower end of the upper connecting sleeve (1) by means of a thread; the upper end of the piston sleeve (3) is connected to the outer wall of the lower end of the upper connecting sleeve (1) by means of a thread; the sliding sleeve (4) is sleeved on the outer wall of the lower connecting sleeve (5) and is placed in the annular space between the piston sleeve (3) and the lower connecting sleeve (5); the sliding sleeve (4) is connected to the lower connecting sleeve (5) by means of a safety pin (17); a through hole is provided on the side wall of the lower connecting sleeve (5), and a locking ball (16) is placed in the through hole; a blind hole matching the through hole for accommodating the locking ball (16) is provided on the outer wall of the joint connecting sleeve (2), the locking ball (16) extends into the blind hole, and the locking ball (16) abuts against the inner wall of the sliding sleeve (4); a locking ball (16) is also provided on the inner wall of the sliding sleeve (4); A withdrawal hole (15) is provided for the locking ball (16) to withdraw, and the withdrawal hole (15) is located above the locking ball (16); a liquid passing hole (20) is provided on the side wall of the lower connecting sleeve (5), and the liquid passing hole (20) corresponds to the space above the sliding sleeve (4); the rotating pin (18) is laterally mounted on the lower connecting sleeve (5), and a blind hole is provided on the outer side of the joint connecting sleeve (2) at a position corresponding to the rotating pin (18), and the end of the rotating pin (18) is inserted into the blind hole; an L-shaped slideway (8) is provided on the outer side of the joint connecting sleeve (2), and the L-shaped slideway (8) is composed of a horizontal section and a vertical section; the slideway pin (19) is laterally mounted on the lower connecting sleeve (5), and the end of the slideway pin (19) is inserted into the horizontal section of the L-shaped slideway (8) to prevent the joint connecting sleeve (2) from axially disengaging from the center tube (6).
5. A fully drillable packer with a detachable safety joint as claimed in claim 1, characterized in that: The joint connection sleeve (2) is a hollow cylindrical structure, the outer diameter of the lower part of which is larger than the outer diameter of the upper part; an annular protrusion (27) is provided on the lower outer wall of the joint connection sleeve (2), and two groups of horizontally arranged blind holes are opened on the upper and lower outer walls above the annular protrusion (27), and a plurality of blind holes in each group are arranged in a circular matrix.
6. A fully drillable unsealing system for a detachable safety joint, characterized in that: The invention comprises at least the detachable safety joint fully drillable packer as claimed in any one of claims 1 to 5, and also comprises a milling tool; the milling tool is used for milling parts on the outside of the liner (11) or the center pipe (6).
7. A fully drillable unsealing system for a detachable safety joint as claimed in claim 6, characterized in that: The milling tool comprises an upper joint (21), a knife barrel (22), a cylindrical knife head (24) and a salvage spear (23) whose inner diameter matches that of a central tube (6); a connecting pipe (28) is arranged at the upper part of the upper joint (21); the upper end of the knife barrel (22) is connected to the lower end of the upper joint (21); the upper end of the salvage spear (23) is detachably connected to the lower end of the connecting pipe (28); the cylindrical knife head (24) is connected to the lower end of the knife barrel (22), and the lower end of the salvage spear (23) extends out of the cylindrical knife head (24); an annular space is arranged between the knife barrel (22) and the salvage spear (23), and between the cylindrical knife head (24) and the salvage spear (23); an axial through hole (25) is axially arranged at the connection between the connecting pipe (28) and the inner wall of the upper joint (21), and the axial through hole (25) connects the annular space with the internal space of the oil pipe string.
8. A fully drillable unsealing system for a detachable safety joint as claimed in claim 7, characterized in that: There is a gap between the lower outer wall of the connecting pipe (28) and the inner wall of the upper joint (21); a through hole for connecting with a salvaging spear (23) is formed on the side wall of the lower end of the connecting pipe (28); and radial through holes (26) are formed at positions corresponding to the lower end of the knife barrel (22) and the connecting pipe (28).
9. A method for unsealing a fully drillable unsealing system with a detachable safety joint, characterized in that: The fully drillable unsealing system for the detachable safety joint as claimed in any one of claims 6 to 8 comprises the following steps: Step 1: lower the fully drillable packer with detachable safety joint into the predetermined position underground to complete the installation of the packer; Step 2: When the fully drillable packer with a detachable safety joint fails to be lifted and unsealed, pressure is applied to the pipe string. The pressure passes through the fluid hole (20) and reaches the upper side of the sliding sleeve (4), pushing the sliding sleeve (4) to cut off the safety pin (17); Step 3: The sliding sleeve (4) slides downward. When the retreat hole (15) on the sliding sleeve (4) is aligned with the locking ball (16), the locking ball (16) is released from the blind hole on the outside of the joint connecting sleeve (2), so that the locking effect of the locking ball (16) is released. At this time, the lower connecting sleeve (5) can rotate relative to the joint connecting sleeve (2); Step 4: The rotating pin (18) is cut off and the lower connecting sleeve (5) is rotated, so that the slideway pin (19) installed on the lower connecting sleeve (5) slides out from the L-shaped slideway (8), thereby separating the safety joint assembly from the detachable safety joint fully drillable unsealing packer body; Step 5: Lift the safety joint assembly and the tubing string above it out of the well; Step 6: The milling tool is lowered into the well through the tubing string. The fishing spear (23) in the milling tool clamps the center pipe (6). The tubing string is rotated to drive the cylindrical cutter head (24) on the milling tool to rotate, and the parts on the outside of the liner (11) or the center pipe (6) are milled to achieve unsealing.