Ultra-short radius sidetracking well flexible pipe external packer

Abstract

The invention relates to the technical field of downhole packer tools, in particular to an ultra-short radius sidetracking well flexible pipe outer packer which comprises an upper connector and a central pipe. The rotary bending device is reasonable and compact in structure and convenient to use, the upper connector and the center pipe can be rotationally bent to form a certain angle through the ball journal and the pressing cap, rigid connection between the upper connector and the center pipe in the prior art is converted into flexible connection, and the rotary bending device can smoothly pass through the inclined face and the deflecting section of the whipstock to reach the preset position; through well mouth pressing and pressure building, the packer can be reliably set on the well wall of a horizontal well section, a well hole is packed, and the purposes of half-way well cementation, staged and staged fracturing, reservoir transformation and the like are achieved; due to the fact that the center pipe can automatically rotate to adjust the angle between the center pipe and the upper connector under the action of well walls with different curvatures or inclined faces, the center pipe can better adapt to small-curvature well holes and irregular well walls, the friction force between the center pipe and the well walls is effectively reduced, and the center pipe is prevented from being clamped in a whipstock or the small-curvature well holes and damaging tools.

Description

Technical Field

[0001] The invention relates to the technical field of downhole packer tools, in particular to an ultra-short radius sidetracking flexible pipe external packer. Background Art

[0002] Ultra-short radius horizontal wells use the original casing in the well to open windows and create inclination, reduce footage, increase oil leakage area, reactivate low-yield and low-efficiency wells, and improve the development effect of thin oil layers and low-permeability oil layers. Packer refers to a downhole tool connected to the downhole pipe string to isolate the annular space between the oil pipe and the oil and gas well casing or the open hole wall.

[0003] The Chinese patent document with publication number CN115234192A discloses a flexible packer suitable for directional wells, which includes an elastic tube, a support member and a driving device. The elastic tube is arranged in series between or at the bottom of multiple oil pipes forming a pipe string, the support member is arranged in the elastic tube, and the support member is slidably arranged in the elastic tube along the radial direction of the elastic tube. The driving device is used to drive the support member to move outward along the radial direction of the elastic tube and push part of the elastic tube to the inner wall of the casing squeezed on the outside of the oil pipe. The elastic tube includes a rubber layer and an intermediate metal mesh layer embedded in the rubber layer. In actual use, the rubber material is easily scratched and worn by the well wall.

[0004] The existing conventional packers have high rigidity and long center tubes. During cementing and completion operations, due to the small curvature radius of the wellbore trajectory of ultra-short radius horizontal wells, the friction resistance of the pipe string with the packer is large, the tool will bend and be easily damaged, and it is difficult to pass through the inclined surface of the whipstock, resulting in construction difficulties. Therefore, a new type of flexible packer suitable for ultra-short radius horizontal wells is urgently needed to solve the above problems. Summary of the invention

[0005] The present invention provides an ultra-short radius side drilling flexible external pipe packer, which overcomes the shortcomings of the above-mentioned prior art and can effectively solve the problems of large rigidity and long center pipe of existing conventional packers. When performing cementing and completion operations, due to the small curvature radius of the wellbore trajectory of the ultra-short radius horizontal well, the friction resistance of the pipe string with the packer is large, the tool will bend and be easily damaged, and it is difficult to pass through the inclined surface of the whipstock, resulting in construction difficulties.

[0006] The technical solution of the present invention is achieved through the following measures: an ultra-short radius side drilling flexible pipe external sealer, including an upper joint and a center pipe, a rotating assembly is provided between the lower part of the upper joint and the upper part of the center pipe, which can bend the center pipe and the upper joint into a certain angle, and the inner cavity of the rotating assembly can connect the inner cavity of the upper joint and the center pipe; a stop cylinder that can only descend in one direction is provided on the outer side of the middle part of the center pipe, and the upper end of the stop cylinder is fixedly installed on the center pipe by at least one circumferentially distributed shear pin, a liquid inlet hole that passes through the inside and outside is provided in the middle part of the center pipe, and a pressure transmission cavity connected to the liquid inlet hole is provided between the inner side of the lower part of the stop cylinder and the outer side of the center pipe; a lower joint is fixedly installed on the outer side of the lower part of the center pipe, and a rubber cylinder is sleeved on the outer side of the center pipe corresponding to the position between the lower joint and the stop cylinder.

[0007] The following are further optimizations and / or improvements to the above technical solutions: The above-mentioned rotating component may include a pressure cap and a ball shaft with an axial flow channel. A ball socket groove opening upward is provided in the middle of the upper end of the center tube. A ball shaft with its lower part located in the ball socket groove is fixedly installed on the inner side of the lower part of the upper joint. A spherical rotating part that can form a rotational connection with the ball socket groove is provided on the outer side of the lower part of the ball shaft. A pressure cap is mounted on the outer side of the upper part of the spherical rotating part, and the inner side of the lower part is fixedly installed with the outer side of the upper part of the center tube.

[0008] The above-mentioned rotating component may also include balls. At least two notches that open upward and penetrate inside and outside are evenly distributed along the circumference on the upper side of the center tube. A hemispherical groove opening outward is provided on the outer side of the middle part of the spherical rotating part corresponding to each notch position. A ball that can move up and down in the notch is provided between each hemispherical groove and the corresponding position on the inner side of the pressure cap.

[0009] The above-mentioned rotating assembly may also include a first sealing ring and a second sealing ring. The first sealing ring is arranged between the outer side of the upper end of the ball shaft and the inner side of the lower part of the upper joint, and the second sealing ring is arranged between the outer side of the lower end of the spherical rotating part and the inner side of the lower end of the ball socket.

[0010] The above-mentioned anti-recoil cylinder may include a liquid cylinder cylinder and a locking ring. The outer side of the middle part of the central tube is provided with a first outer ring groove, a second outer ring groove and a third outer ring groove with decreasing outer diameters from top to bottom; a liquid cylinder cylinder is provided in the first outer ring groove, and the lower end of the liquid cylinder cylinder is located below the liquid inlet hole. The upper end of the liquid cylinder cylinder and the central tube are fixed together by at least one circumferentially distributed shear pin; a locking ring, a threaded inverted tooth and a limiting outer ring platform are provided in the second outer ring groove from top to bottom, and the outer diameter of the limiting outer ring platform is larger than the outer diameter of the threaded inverted tooth. The inner side of the lower part of the locking ring is provided with an anti-recoil inverted tooth which can engage with the threaded inverted tooth to prevent the liquid cylinder cylinder from moving upward. Teeth, a transmission outer inverted tooth is provided on the outside of the locking ring, and a transmission inner inverted tooth which can mesh with the transmission outer inverted tooth and drive the locking ring downward is provided on the inner side of the liquid cylinder barrel corresponding to the position of the locking ring; a stopping inner ring platform whose lower part is sleeved on the outer side of the limiting outer ring platform is provided in the liquid cylinder barrel corresponding to the lower side position of the locking ring; a pressure-bearing inner ring platform whose inner end is located in the third outer ring groove is provided in the liquid cylinder barrel corresponding to the lower side position of the stopping inner ring platform, and a pressure-bearing inner ring platform whose inner end is located in the third outer ring groove is provided on the inner side of the upper part of the pressure-bearing inner ring platform, and a pressure-bearing inner ring groove connected with the liquid inlet hole is provided on the inner side of the upper end of the pressure-bearing inner ring groove, and the inner side of the upper end of the pressure-bearing inner ring groove is a cone-shaped with a larger upper part and a smaller lower part, and a pressure transmission cavity is formed between the upper part of the third outer ring groove and the pressure-bearing inner ring groove.

[0011] The above-mentioned anti-retraction cylinder may also include a third sealing ring, and a third sealing ring is provided between the stopping inner ring platform and the limiting outer ring platform, and between the lower part of the pressure-bearing inner ring platform and the center tube.

[0012] The above-mentioned lower joint may include a lower pipe joint, a T-shaped connecting sleeve and a fixing ring. The T-shaped connecting sleeve is installed on the outer sleeve of the center pipe corresponding to the lower side of the rubber cylinder. The lower pipe joint is threadedly connected to the outer side from the middle to the lower part of the T-shaped connecting sleeve. A stopping inner ring groove is provided on the inner side of the middle part of the lower pipe joint. A stopping outer ring groove is provided on the outer side of the lower end of the center pipe corresponding to the position of the stopping inner ring groove. A fixing ring is provided between the stopping outer ring groove and the stopping inner ring groove, and the upper end of the fixing ring is abutted against the lower end surface of the T-shaped connecting sleeve.

[0013] A first limiting groove opening downward may be provided in the middle of the lower side of the above-mentioned anti-retraction cylinder, and a first limiting boss with a lower end fixedly installed with the upper side of the rubber cylinder may be provided in the limiting groove; a second limiting groove opening upward may be provided in the middle of the upper side of the lower joint, and a second limiting boss with an upper end fixedly installed with the lower side of the rubber cylinder may be provided in the second limiting groove.

[0014] The invention has a reasonable and compact structure and is easy to use. The upper joint and the central tube can be rotated and bent into a certain angle through the ball shaft and the pressure cap, and the rigid connection between the two in the prior art is converted into a flexible connection, so that the invention can smoothly pass through the inclined surface and the deflection section of the whipstock to reach a predetermined position. Through wellhead pressure and pressure holding, the invention can be reliably seated on the wellbore wall of the horizontal well section to isolate the wellbore, thereby achieving the purposes of half-way cementing, staged and graded fracturing, reservoir transformation, etc.; because the central tube can automatically rotate and adjust the angle between it and the upper joint under the action of wellbore walls or inclined surfaces with different curvatures, it can better adapt to wellbores with small curvatures and irregular wellbores, effectively reducing the friction between the invention and the wellbore wall, preventing it from being stuck in the whipstock or in a wellbore with small curvature, damaging the tool, and improving the work efficiency. It has the characteristics of simple construction, safety, reliability, and cost saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Attached Figure 1 It is a schematic diagram of the main semi-sectional structure of the upper half of an embodiment of the present invention.

[0016] Attached Figure 2 It is a schematic diagram of the front view and semi-section structure of the lower half of an embodiment of the present invention.

[0017] Attached Figure 3 For attachment Figure 1 Schematic diagram of the cross-sectional structure enlarged at AA in the middle.

[0018] Attached Figure 4 It is a schematic diagram of the front half-section structure of the embodiment of the present invention in use state.

[0019] The codes in the accompanying drawings are: 1 is an upper joint, 2 is a center tube, 3 is a shear pin, 4 is a liquid inlet hole, 5 is a pressure transmission chamber, 6 is a rubber cylinder, 7 is a pressure cap, 8 is an axial flow channel, 9 is a ball shaft, 10 is a spherical rotating part, 11 is a ball, 12 is a notch, 13 is a first sealing ring, 14 is a second sealing ring, 15 is a liquid cylinder, 16 is a locking ring, 17 is a threaded inverted tooth, 18 is a limiting outer ring platform, 19 is a stop inner ring platform, 20 is a pressure-bearing inner ring platform, 21 is a third sealing ring, 22 is a lower pipe joint, 23 is a T-type connecting sleeve, 24 is a fixing ring, 25 is a first limiting boss, and 26 is a second limiting boss. DETAILED DESCRIPTION

[0020] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0021] In the present invention, for the convenience of description, the relative position relationship of each component is described according to the attached Figure 1 The positional relationships such as front, back, top, bottom, left, and right are described according to the layout directions of the drawings in the specification.

[0022] The present invention will be further described below in conjunction with embodiments and drawings: Embodiment 1: As attached Figure 1 , 2 As shown in Figures 3 and 4, the ultra-short radius side drilling flexible pipe external sealer includes an upper joint 1 and a center pipe 2. A rotating assembly is provided between the lower part of the upper joint 1 and the upper part of the center pipe 2, which can bend the center pipe 2 and the upper joint 1 into a certain angle, and the inner cavity of the rotating assembly can connect the inner cavities of the upper joint 1 and the center pipe 2; a stop cylinder that can only go downward in one direction is provided on the outer side of the middle part of the center pipe 2, and the upper end of the stop cylinder is fixedly installed on the center pipe 2 by at least one circumferentially distributed shear pin 3; a liquid inlet hole 4 that passes through the inside and outside is provided in the middle part of the center pipe 2, and a pressure transmission cavity 5 connected to the liquid inlet hole 4 is provided between the inner side of the lower part of the stop cylinder and the outer side of the center pipe 2; a lower joint is fixedly installed on the outer side of the lower part of the center pipe 2, and a rubber cylinder 6 is sleeved on the outer side of the center pipe 2 corresponding to the position between the lower joint and the stop cylinder.

[0023] During use, the upper joint 1 is first connected to the cemented completion pipe string, and then the lower joint is connected to the blind plate. After entering the well, in the vertical well section, the upper joint 1 and the central pipe 2 will not bend due to gravity, and thus maintain a vertical state. When the present invention passes through the inclined surface of the whipstock, the central pipe 2 is automatically twisted and bent to a certain angle (such as 1.5 degrees) between the central pipe 2 and the upper joint 1 through the rotating assembly under the guidance of the inclined surface of the whipstock. Figure 4 As shown in the figure, the upper joint 1 and the center pipe 2 gradually enter the inclined well section, so that the present invention can quickly and smoothly pass through the inclined surface of the bend device at a certain angle, preventing the present invention from being stuck in the bend device. When the present invention passes through an ultra-short radius horizontal well or a small curvature wellbore (i.e., the turning radius of this wellbore is relatively small), the upper joint 1 and the center pipe 2 will be subjected to the top pressure of the wellbore wall with different curvatures. Since the center pipe 2 will enter the wellbore turning point first, the center pipe 2 will be subjected to a greater torsional force, so that it and the upper joint 1 are automatically twisted and bent to a suitable angle through the rotating component, so that the present invention can quickly pass through this position, preventing the present device from being stuck in the wellbore with a small curvature bend. At the same time, it can also effectively reduce the friction between the present invention and the wellbore wall to prevent tool damage. After the present invention is lowered to a predetermined position according to the design parameters, pressure is pumped from the wellhead, and the pressure is held back through the blind plate. High-pressure liquid flows into the pressure transmission chamber 5 through the liquid inlet hole 4. When the pressure generated by the high-pressure liquid accumulated in the pressure transmission chamber 5 shears off the shear pin 3, the stop cylinder slides downward to squeeze the rubber cylinder 6, causing the rubber cylinder 6 to deform and bulge outward to seal the open hole section. After the wellhead stops pumping pressure, the stop cylinder, which can only descend in one direction, will not slide upward, thereby causing the rubber cylinder 6 to remain in a compressed and bulging state and unable to rebound, thereby ensuring that the present invention can effectively perform isolation operations, ensure the stability of the isolation, and ensure the safety of the well completion operations.

[0024] According to the requirements, the rotating assembly should be able to bend the upper joint 1 and the center pipe 2 to a certain angle and connect the flow channel between the upper joint 1 and the center pipe 2. The rotating assembly can be realized by a hinge connector and a flexible material tube, or by a spherical hinge joint or a joint bearing assembly, or by a bellows or a flexible material tube; the anti-retraction cylinder can be realized by a spring plunger or an elastic retaining ring and a slot combination structure or an elastic retaining ring or a spring sheet inverted tooth structure, or it can be realized based on the anti-retraction structure between the ratchet teeth of the ratchet and the anti-retraction pawl, or it can be realized based on an inverted tooth structure that can only slide in one direction and can hook each other in the reverse direction; the fixed installation between the center pipe 2 and the lower joint can be a detachable installation or a non-detachable installation. In order to facilitate the replacement of the rubber cylinder 6, the center pipe 2 and the lower joint in this embodiment are connected together by threads; in order to facilitate the connection with the completion well pipe string, the inner side of the upper end of the upper joint 1 is provided with an internal thread matching the external thread of the pipe string connection, and the outer side of the lower end of the lower joint is provided with an external thread.

[0025] The present invention has a reasonable and compact structure and is easy to use. The upper joint 1 and the central pipe 2 can be rotated and bent into a certain angle, so that the rigid connection between the two in the prior art is converted into a flexible connection, so that the present invention can smoothly pass through the inclined surface and the deflection section of the whipstock to reach a predetermined position. Through wellhead pressure and pressure holding, the present invention can be reliably seated on the wellbore wall of the horizontal well section to isolate the wellbore, thereby achieving the purposes of half-way cementing, staged and graded fracturing, and reservoir transformation. Since the central pipe 2 can automatically rotate and adjust the angle between it and the upper joint 1 under the action of wellbore walls or inclined surfaces with different curvatures, it can better adapt to wellbores with small curvatures and irregular wellbores, effectively reducing the friction between the present invention and the wellbore wall, preventing it from being stuck in the whipstock or in a wellbore with small curvature, damaging the tool, and improving work efficiency. It has the characteristics of simple construction, safety, reliability, and cost saving.

[0026] The ultra-short radius sidetracking flexible external packer can be further optimized and / or improved according to actual needs: Embodiment 2: As attached Figure 1 , 2 As shown in Figures 3 and 4, the rotating assembly includes a pressure cap 7 and a ball shaft 9 provided with an axial flow channel 8. A ball socket groove opening upward is provided in the middle of the upper end of the center tube 2. The ball shaft 9 located in the ball socket groove is fixedly installed on the inner side of the lower part of the upper joint 1. A spherical rotating part 10 which can form a rotational connection with the ball socket groove is provided on the outer side of the lower part of the ball shaft 9. The pressure cap 7 which is fixedly installed together with the inner side of the lower part and the outer side of the upper part of the center tube 2 is mounted on the outer side of the upper part of the spherical rotating part 10.

[0027] By such arrangement, the spherical rotating part 10 on the ball shaft 9 and the ball socket groove matched with its shape can form a spherical joint, so that the central tube 2 can automatically rotate and bend to a certain angle with the upper joint 1, so that the present invention can pass through a small curvature wellbore or a bevel device slope without being stuck; the axial flow channel 8 in the ball shaft 9 facilitates the high-pressure liquid flow to quickly enter the central tube 2; and the pressure cap 7 can effectively prevent the spherical rotating part 10 from separating from the ball socket groove.

[0028] According to requirements, the fixed installation between the upper joint 1 and the ball shaft 9 and between the pressure cap 7 and the center tube 2 can be achieved by a detachable installation or a non-detachable installation in the existing known technology. To facilitate inspection, replacement and maintenance, a threaded connection is used in this embodiment; in addition, in order to make the outer diameter of the present invention consistent, a pressure cap outer ring groove can be provided on the outer side of the upper end of the center tube 2, and the center tube 2 is screwed to the pressure cap 7 through the pressure cap outer ring groove.

[0029] Embodiment 3: As attached Figure 1 , 2 As shown in Figures 3 and 4, the rotating assembly also includes a ball 11. At least two notches 12 opening upward and penetrating inside and outside are evenly distributed along the circumference of the upper side of the center tube 2. A hemispherical groove opening outward is provided on the outer side of the middle part of the spherical rotating part 10 corresponding to the position of each notch 12. A ball 11 capable of moving up and down in the notch 12 is provided between each hemispherical groove and the corresponding position on the inner side of the pressure cap 7.

[0030] By such arrangement, the ball 11 can leave enough clearance between the upper end of the pressure cap 7 and the spherical rotating part 10, so as to ensure that the center pipe 2 has enough space to rotate and bend, and prevent the pressure cap 7 and the spherical rotating part 10 from being worn; in this way, when the present invention enters the well through the inclined surface, the pressure cap 7 and the spherical rotating part 10 can be connected by rolling through the ball 11, and the axial force and torque are transmitted to the center pipe 2 through the ball 11, so that the center pipe 2 and the upper joint 1 can be automatically bent into a certain angle, so that the present invention can smoothly pass through the inclined surface of the whipstock or the small curvature section of the ultra-short radius wellbore, and go down to the predetermined position of the horizontal well section. According to the demand, in order to achieve better support and transmission effects, four balls 11 are provided in this embodiment.

[0031] Embodiment 4: As attached Figure 1 , 2 As shown in Figures 3 and 4, the rotating assembly also includes a first sealing ring 13 and a second sealing ring 14. The first sealing ring 13 is provided between the outer side of the upper end of the ball shaft 9 and the inner side of the lower part of the upper joint 1, and the second sealing ring 14 is provided between the outer side of the lower end of the spherical rotating part 10 and the inner side of the lower end of the ball socket.

[0032] This arrangement can effectively prevent high-pressure liquid from leaking from the thread gap between the ball shaft 9 and the upper joint 1 and the rotation gap between the spherical rotating part 10 and the central tube 2, thereby leaking the pressure of the inner cavity of the present invention.

[0033] Embodiment 5: As attached Figure 1 , 2 As shown in , 3 and 4, the back-stopping cylinder includes a liquid cylinder barrel 15 and a locking ring 16. The outer side of the middle part of the central tube 2 is provided with a first outer ring groove, a second outer ring groove and a third outer ring groove with outer diameters decreasing successively from top to bottom; the first outer ring groove is provided with a liquid cylinder barrel 15 whose lower end is located below the liquid inlet hole 4, and the upper end of the liquid cylinder barrel 15 is fixedly installed with the central tube 2 by at least one shear pin 3 distributed in a circumference; the second outer ring groove is provided with a locking ring 16, a threaded inverted tooth 17 and a limiting outer ring platform 18 in sequence from top to bottom, and the outer diameter of the limiting outer ring platform 18 is larger than the outer diameter of the threaded inverted tooth 17, and the inner side of the lower part of the locking ring 16 is provided with a The locking ring 16 is provided with a transmission outer inverted tooth on the outside, and the inner side of the liquid cylinder 15 corresponding to the position of the locking ring 16 is provided with a transmission inner inverted tooth that can mesh with the transmission outer inverted tooth to drive the locking ring 16 downward; the liquid cylinder 15 corresponding to the lower side of the locking ring 16 is provided with a stop inner ring platform 19 whose lower part is sleeved on the outer side of the limiting outer ring platform 18; the liquid cylinder 15 corresponding to the lower side of the stop inner ring platform 19 is provided with a pressure-bearing inner ring platform 20 whose inner end is located in the third outer ring groove, and the inner side of the upper part of the pressure-bearing inner ring platform 20 is provided with a pressure-bearing inner ring groove connected with the liquid inlet hole 4, and the inner side of the upper end of the pressure-bearing inner ring groove is a cone-shaped with a larger upper part and a smaller lower part, and a pressure transmission chamber 5 is formed between the upper part of the third outer ring groove and the pressure-bearing inner ring groove.

[0034] During use, the wellhead is pressurized and the shear pin 3 is cut off by holding the pressure. Then, the liquid cylinder barrel 15 drives the locking ring 16 to slide down along the axis of the central tube 2 under the push of the high-pressure liquid flow. In this process, after the transmission inner inverted teeth are meshed with the transmission outer inverted teeth, the locking ring 16 slides down with the liquid cylinder barrel 15, and the anti-retraction inverted teeth and the threaded inverted teeth 17 are gradually meshed, but the anti-retraction inverted teeth will not prevent the liquid cylinder barrel 15 from sliding downward. When the locking ring 16 is supported by the upper end of the limiting outer ring platform 18, the rubber tube 6 is just completely extruded and formed to block the open hole section; after stopping the pressure, the anti-retraction inverted teeth will firmly hang on the threaded inverted teeth 17 to prevent the locking ring 16 from going up, and at the same time, the upper end surface of the stopping inner ring platform 19 will be stuck by the lower end surface of the locking ring 16, so as to prevent the liquid cylinder barrel 15 from rebounding upward, thereby ensuring the strength and stability of the seal, so that the present invention can be reliably sealed in the wellbore at a predetermined position.

[0035] According to the requirements, in this embodiment, the tooth surface shape of the threaded inverted tooth 17 can be a right triangle with the hypotenuse inclined downward and the right angle side at the bottom, and the tooth surface of the stop inverted tooth can be a right triangle with the hypotenuse inclined downward and the right angle side at the top; the tooth surface shape of the transmission inner inverted tooth can be a right triangle with the hypotenuse inclined upward and the right angle side at the bottom, and the tooth surface shape of the transmission outer inverted tooth can be a right triangle with the hypotenuse inclined upward and the right angle side at the top; the threaded inverted tooth 17 and the limiting outer ring platform 18 can be formed in one piece with the center tube 2; in order to facilitate the support of the locking ring 16 by the limiting outer ring platform 18, the outer diameter of the limiting outer ring platform 18 is usually much larger than the outer diameter of the threaded inverted tooth 17. In addition, by setting the pressure-bearing inner ring groove to reduce the volume of the pressure transmission chamber 5, the action of the liquid cylinder barrel 15 can also be faster, the efficiency of the setting operation is improved, and the operation time is saved.

[0036] Embodiment 6: As attached Figure 1 , 2 As shown in , 3 and 4 , the anti-retraction cylinder also includes a third sealing ring 21 , and a third sealing ring 21 is provided between the stopping inner ring platform 19 and the limiting outer ring platform 18 , and between the lower part of the pressure-bearing inner ring platform 20 and the center tube 2 .

[0037] During use, the third sealing ring 21 can effectively seal the gaps at the upper and lower parts of the pressure transmission chamber 5, thereby accelerating the action time of the liquid cylinder 15 and effectively improving the setting efficiency of the present invention.

[0038] Embodiment 7: As attached Figure 1 , 2 As shown in Figures 3 and 4, the lower joint includes a lower pipe joint 22, a T-shaped connecting sleeve 23 and a fixing ring 24. The T-shaped connecting sleeve 23 is sleeved on the outer side of the center pipe 2 corresponding to the lower side of the rubber sleeve 6. The lower pipe joint 22 is threadedly connected to the outer side from the middle to the lower part of the T-shaped connecting sleeve 23. A stopping inner ring groove is provided on the inner side of the middle part of the lower pipe joint 22. A stopping outer ring groove is provided on the outer side of the lower end of the center pipe 2 corresponding to the position of the stopping inner ring groove. A fixing ring 24 whose upper end abuts against the lower end surface of the T-shaped connecting sleeve 23 is provided between the stopping outer ring groove and the stopping inner ring groove.

[0039] By such arrangement, the lower joint and the central tube 2 can be quickly disassembled, and the fixing ring 24 can increase the connection strength between the central tube 2 and the lower joint, and can effectively prevent the lower joint from being disengaged from the central tube 2. According to the requirements, in order to facilitate the installation of the fixing ring 24, the fixing ring 24 can be realized by two fixing half rings with openings facing each other and forming a circular ring.

[0040] Embodiment 8: As attached Figure 1 , 2As shown in , 3 and 4, a first limiting groove with an opening downward is provided in the middle of the lower side of the anti-retraction cylinder, and a first limiting boss 25 with a lower end fixedly mounted to the upper side of the rubber cylinder 6 is provided in the limiting groove; a second limiting groove with an opening upward is provided in the middle of the upper side of the lower joint, and a second limiting boss 26 with an upper end fixedly mounted to the lower side of the rubber cylinder 6 is provided in the second limiting groove.

[0041] The bite fixation between the first limiting groove and the first limiting boss 25 and the bite fixation between the second limiting boss 26 and the second limiting groove can effectively improve the stability of the rubber sleeve 6 and prevent the reliability of the setting seal from being affected due to the rubber sleeve 6 being pressed off.

[0042] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. An ultra-short radius sidetracking flexible external packer, characterized in that It includes an upper joint and a central tube, a rotating assembly is provided between the lower part of the upper joint and the upper part of the central tube, which can bend the central tube and the upper joint into a certain angle, and the inner cavity of the rotating assembly can connect the inner cavities of the upper joint and the central tube; a stop cylinder which can only go downward in one direction is provided on the outer side of the middle part of the central tube, and the upper end of the stop cylinder is fixedly installed on the central tube by at least one circumferentially distributed shear pin, a liquid inlet hole which passes through inside and outside is provided in the middle part of the central tube, and a pressure transmission cavity connected with the liquid inlet hole is provided between the inner side of the lower part of the stop cylinder and the outer side of the central tube; a lower joint is fixedly installed on the outer side of the lower part of the central tube, and a rubber cylinder is mounted on the outer side of the central tube corresponding to the position between the lower joint and the stop cylinder.

2. The ultra-short radius side drilling flexible external packer according to claim 1 is characterized in that The rotating assembly includes a pressure cap and a ball shaft with an axial flow channel. A ball socket groove opening upward is provided in the middle of the upper end of the center tube. A ball shaft with its lower part located in the ball socket groove is fixedly installed on the inner side of the lower part of the upper joint. A spherical rotating part that can form a rotational connection with the ball socket groove is provided on the outer side of the lower part of the ball shaft. A pressure cap is mounted on the outer side of the upper part of the spherical rotating part, and the inner side of the lower part is fixedly installed with the outer side of the upper part of the center tube.

3. The ultra-short radius sidetracking flexible external packer according to claim 2 is characterized in that The rotating component also includes balls. There are at least two notches evenly distributed along the circumference on the upper side of the center tube, which are open upward and penetrate inside and outside. A hemispherical groove opening outward is provided on the outer side of the middle part of the spherical rotating part corresponding to each notch position. A ball that can move up and down in the notch is provided between each hemispherical groove and the corresponding position on the inner side of the pressure cap.

4. The ultra-short radius sidetracking flexible external packer according to claim 2 or 3, characterized in that The rotating assembly also includes a first sealing ring and a second sealing ring. The first sealing ring is arranged between the outer side of the upper end of the ball shaft and the inner side of the lower part of the upper joint, and the second sealing ring is arranged between the outer side of the lower end of the spherical rotating part and the inner side of the lower end of the ball socket.

5. The ultra-short radius sidetracking flexible external packer according to claim 1, 2 or 3, characterized in that The anti-retraction cylinder includes a liquid cylinder and a locking ring. The outer side of the middle part of the central tube is provided with a first outer ring groove, a second outer ring groove and a third outer ring groove with decreasing outer diameters from top to bottom; a liquid cylinder with its lower end located below the liquid inlet hole is provided in the first outer ring groove, and the upper end of the liquid cylinder and the central tube are fixed together by at least one circumferentially distributed shear pin; a locking ring, a threaded reverse tooth and a limiting outer ring platform are provided in the second outer ring groove from top to bottom, and the outer diameter of the limiting outer ring platform is larger than the outer diameter of the threaded reverse tooth, and an anti-retraction reverse tooth that can mesh with the threaded reverse tooth to prevent the liquid cylinder from moving upward is provided on the inner side of the lower part of the locking ring. A transmission outer inverted tooth is provided on the outside of the locking ring, and a transmission inner inverted tooth which can mesh with the transmission outer inverted tooth and drive the locking ring downward is provided on the inner side of the liquid cylinder corresponding to the position of the locking ring; a stopping inner ring platform whose lower part is mounted on the outer side of the limiting outer ring platform is provided in the liquid cylinder corresponding to the lower side of the locking ring; a pressure-bearing inner ring platform whose inner end is located in the third outer ring groove is provided in the liquid cylinder corresponding to the lower side of the stopping inner ring platform, and a pressure-bearing inner ring groove connected with the liquid inlet hole is provided on the inner side of the upper part of the pressure-bearing inner ring platform, and the inner side of the upper end of the pressure-bearing inner ring groove is in the shape of a cone with a larger upper part and a smaller lower part, and a pressure transmission chamber is formed between the upper part of the third outer ring groove and the pressure-bearing inner ring groove.

6. The ultra-short radius sidetracking flexible external packer according to claim 5, characterized in that The anti-retraction cylinder also includes a third sealing ring, and a third sealing ring is arranged between the stopping inner ring platform and the limiting outer ring platform, and between the lower part of the pressure-bearing inner ring platform and the central tube.

7. The ultra-short radius sidetracking flexible external packer according to claim 1, 2, 3 or 6, characterized in that The lower joint includes a lower pipe joint, a T-shaped connecting sleeve and a fixing ring. The T-shaped connecting sleeve is installed on the outer sleeve of the center pipe corresponding to the lower side of the rubber cylinder. The lower pipe joint is threadedly connected to the outer side from the middle to the lower part of the T-shaped connecting sleeve. A stopping inner ring groove is provided on the inner side of the middle part of the lower pipe joint. A stopping outer ring groove is provided on the outer side of the lower end of the center pipe corresponding to the position of the stopping inner ring groove. A fixing ring is provided between the stopping outer ring groove and the stopping inner ring groove, the upper end of which is abutted against the lower end surface of the T-shaped connecting sleeve.

8. The ultra-short radius sidetracking flexible external packer according to claim 4, characterized in that The lower joint includes a lower pipe joint, a T-shaped connecting sleeve and a fixing ring. The T-shaped connecting sleeve is installed on the outer sleeve of the center pipe corresponding to the lower side of the rubber cylinder. The lower pipe joint is threadedly connected to the outer side from the middle to the lower part of the T-shaped connecting sleeve. A stopping inner ring groove is provided on the inner side of the middle part of the lower pipe joint. A stopping outer ring groove is provided on the outer side of the lower end of the center pipe corresponding to the position of the stopping inner ring groove. A fixing ring is provided between the stopping outer ring groove and the stopping inner ring groove, the upper end of which is abutted against the lower end surface of the T-shaped connecting sleeve.

9. The ultra-short radius sidetracking flexible external packer according to claim 5, characterized in that The lower joint includes a lower pipe joint, a T-shaped connecting sleeve and a fixing ring. The T-shaped connecting sleeve is installed on the outer sleeve of the center pipe corresponding to the lower side of the rubber cylinder. The lower pipe joint is threadedly connected to the outer side from the middle to the lower part of the T-shaped connecting sleeve. A stopping inner ring groove is provided on the inner side of the middle part of the lower pipe joint. A stopping outer ring groove is provided on the outer side of the lower end of the center pipe corresponding to the position of the stopping inner ring groove. A fixing ring is provided between the stopping outer ring groove and the stopping inner ring groove, the upper end of which is abutted against the lower end surface of the T-shaped connecting sleeve.

10. The ultra-short radius sidetracking flexible external packer according to claim 1, 2, 3, 6, 8 or 9, characterized in that A first limiting groove opening downward is provided in the middle of the lower side of the anti-retraction cylinder, and a first limiting boss with a lower end fixedly installed with the upper side of the rubber cylinder is provided in the limiting groove; a second limiting groove opening upward is provided in the middle of the upper side of the lower joint, and a second limiting boss with an upper end fixedly installed with the lower side of the rubber cylinder is provided in the second limiting groove.

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