Fracturing pressure-bearing tubular column for sidetracking well

Abstract

The utility model discloses a sidetrack well fracturing pressure-bearing pipe column, which comprises a tail pipe hanging pipe column and an insertion pipe column, the tail pipe hanging pipe column comprises a tie-back barrel, a tail pipe hanging device and a tail pipe which are sequentially connected from top to bottom, the insertion pipe column comprises a tie-back oil pipe and a sealing insertion pipe which are sequentially connected from top to bottom, and the upper end of the tie-back barrel is provided with a tie-back insertion opening. An anchoring sealing plug is arranged at the lower end of the sealing inserting pipe, the anchoring sealing plug is of a split structure, and the anchoring sealing plug is connected with the tie-back inserting opening through tie-back threads; the tie-back thread is provided with asymmetric double-angle thread teeth. The tail pipe hanging device is a hydraulic tail pipe hanging device. Repeated tie-back can be achieved, the butt-joint pipe column can be replaced according to requirements, and the butt-joint efficiency is high; the hydraulic drilling liner hanger is innovatively adopted, after the sealing plug is inserted into the tie-back barrel, the pressure difference resistance is 70 MPa, compared with the pressure difference resistance of 50 MPa of a conventional sidetracking well, the pressure difference resistance is improved by 20 MPa, and the requirement for the pressure difference resistance of 70 MPa in fracturing construction is met.

Description

Technical Field

[0001] The utility model relates to the technical field of oil and gas well development, in particular to a side drilling well fracturing pressure-bearing pipe string. Background Art

[0002] The three common existing φ139.7mm original well casing + φ95.3mm liner slim hole casing completion sidetracking fracturing strings have the following disadvantages:

[0003] Openhole completion and staged fracturing string: The openhole section of the wellbore is divided into several sections. Packers are placed at the corresponding locations, and sliding sleeves are placed at the corresponding locations requiring modification. The packers and sliding sleeves are connected to form a string. The completion string is run to the designed location, the openhole packers are set and suspended, and then the drill is pulled out. Before fracturing, a tieback string is run through tubing for tieback. During fracturing, fracturing balls are dropped to sequentially open the sliding sleeves, thus achieving the purpose of staged fracturing. For water-driven low-permeability reservoirs, openhole completion and staged fracturing string use openhole completion, which can easily flood the reservoir and make water control difficult later.

[0004] Small tubing stuck fracturing string: This string utilizes Ø89mm tubing, Φ60.3mm tubing fracturing, a DK344-78 packer, and a Φ60.3mm tubing fracturing system to protect the hanger. This string tooling is complex, and the packer and other tool strings can easily become stuck in the wellbore, making post-processing difficult.

[0005] Coiled tubing multi-stage fracturing string: The coiled tubing is connected to the tool string, and a sandblasting perforating tool is run. Positioned to the designated location using the MCCL coupling locator, cluster sandblasting is performed using an appropriate displacement rate, and perforation sand displacement is completed. The coiled tubing is removed, the flowline reversed, and casing volume fracturing is performed. At the end of the pumping phase, a tail-chasing high-concentration sand plug is used for staged sand filling. This string is required for casing volume fracturing. The casing pressure in the sidetracked well is low, ≤15MPa, which does not meet the pressure requirements of casing fracturing.

[0006] Aiming at the problems existing in the three common φ139.7mm original well casing + φ95.3mm tail pipe slim hole casing completion side drilling fracturing strings and the problem that the old wellbore casing of the side drilling well is in poor condition and has insufficient pressure bearing capacity (fracturing construction requires a pressure resistance of 70MPa), research and invention were carried out. The utility model adopts tail pipe + hydraulic tail pipe hanging device + tie-back tube + sealing plug tube + tie-back oil pipe to establish a side drilling fracturing pressure string, realizing the full-diameter general fracturing transformation of slim hole casing completion side drilling.

[0007] Announcement No.: CN111472690B discloses a side drilling well completion method. By installing an integrated tail pipe hanging and tieback tool on the upper part of the small-diameter casing, the small-diameter casing is cemented and hung in the original wellbore, and a tieback tube is left on the upper part of the small-diameter casing. During fracturing construction, a sealing cannula can be connected with the small-diameter casing and lowered into the side drilling well. The sealing cannula is inserted into the tieback tube to form a wellbore similar to a new well, realizing the full diameter of the side drilling wellbore, improving the pressure bearing capacity of the entire wellbore, and creating conditions for subsequent multi-layer and segment transformation and water-insulating oil production in the reservoir.

[0008] The tie-back integrated tool used in the prior art can only be disconnected by back-breaking, resulting in low operating efficiency.

[0009] Publication number: CN102392615A, discloses an oil pipe return insertion sealing device, including a center pipe and a return sealing cylinder; a dynamic sealing mechanism is sheathed on the outer sleeve of the center pipe, and the lower end of the center pipe is connected to the introduction coupling. The dynamic sealing mechanism contacts the inner wall of the return sealing cylinder and can dynamically seal.

[0010] This prior art is a sliding plug seal with no connection force, and there is a risk of accidental detachment of the tubing string.

[0011] Announcement No.: CN109267943B discloses a tieback pipe string, including a pipe body and a tieback plug connected to the lower end of the pipe body for sealing and assembling with a tieback tube. The pipe body is provided with an anchor, and the pipe body is also provided with an open hole packer. The second or multiple sealing is achieved by the open hole packer that is set. At the same time, the anchoring effect of the anchor ensures that the tieback plug will not be pushed out of the tieback tube when the well bottom is under high pressure for a long time or instantaneous high pressure. While ensuring the assembly between the tieback tube and the tieback plug, the sealing performance of the tieback pipe string can also be guaranteed.

[0012] The prior art is a sliding plug seal, in which an anchor is provided to prevent it from coming out, which increases the number of pipe string docking operations, increases the docking time, and affects work efficiency.

[0013] In short, the technical solutions of the above-disclosed technologies, the technical problems to be solved and the beneficial effects produced are all different from those of the present utility model. Regarding the more technical features, technical problems to be solved and the beneficial effects of the present utility model, the above-disclosed technical documents do not provide any technical inspiration. Utility Model Content

[0014] In view of the above-mentioned defects in the prior art, the purpose of the present invention is to provide a side drilling well fracturing pressure-bearing tubing string.

[0015] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0016] A side drilling fracturing pressure-bearing tubing string includes a tail pipe hanging string and a plug-in pipe string. The tail pipe hanging string includes a tie-back tube, a tail pipe hanging device, and a tail pipe connected in sequence from top to bottom. The plug-in pipe string includes a tie-back oil pipe and a sealing plug-in pipe connected in sequence from top to bottom. A tie-back socket is provided at the upper end of the tie-back tube, and an anchor sealing plug is provided at the lower end of the sealing plug-in pipe. The anchor sealing plug is a petal structure, and the anchor sealing plug is connected to the tie-back socket through a tie-back thread; the tie-back thread is provided with asymmetric double-angle threads.

[0017] Furthermore, the asymmetric dual-angle thread includes an upward-lifting contact tooth surface and a downward-lifting contact tooth surface;

[0018] Specifically, the angle between the lifting contact tooth surface and the lifting direction is 45°-70°;

[0019] Specifically, the angle between the lowering contact tooth surface and the lowering direction is 15°-30°.

[0020] Furthermore, a transition surface is provided between the upward contact tooth surface and the downward contact tooth surface.

[0021] Furthermore, the return socket is provided with an internal return thread, and the anchor sealing plug is provided with an external return thread.

[0022] Furthermore, a sealing section is provided above the internal return thread of the return socket, and a sealing ring group is fixedly provided above the external return thread on the outer wall of the anchor sealing plug, and the sealing ring group can contact and seal with the sealing section.

[0023] Furthermore, the tie-back thread is a reverse thread.

[0024] Furthermore, the liner suspension device is a hydraulic liner suspension device, and the hydraulic liner suspension device includes a liner hanger and a hydraulic loading pipe connected in sequence from top to bottom;

[0025] Specifically, the liner hanger includes a central tube, and a central tube outer wall is sleeved with a straightening mechanism, a hydraulic drive mechanism, and a suspension anchoring mechanism from top to bottom;

[0026] Specifically, a ball seat is fixed in the hydraulic loading pipe via conductive shear nails.

[0027] Furthermore, the outer wall of the central tube is provided with a first limiting ring and a second limiting ring from top to bottom;

[0028] Specifically, the hydraulic drive mechanism includes a hydraulic cylinder, which is provided with a limit pin, a pressure ring, and a start shear pin; the limit pin is located between the first limit ring and the second limit ring, the pressure ring is located below the second limit ring, and the start shear pin radially penetrates the pressure ring and is embedded in the center tube;

[0029] Specifically, the central tube is provided with a pressure transmission hole between the second limiting ring and the pressure ring, the pressure ring contacts the outer wall of the central tube and is sealed, and the second limiting ring contacts the inner wall of the hydraulic cylinder and is sealed.

[0030] Furthermore, the outer wall of the lower end of the central tube is connected with a cone sleeve;

[0031] Specifically, the suspension anchoring mechanism includes a slip, which is connected to a hydraulic cylinder. The slip is provided with a conical surface facing inwards of the central tube, and the upper end of the cone sleeve is provided with a conical surface facing outwards. The slip can be pushed out by the cone sleeve when it moves downwards, and slip teeth are provided on the outer surface of the slip.

[0032] Specifically, the upper end of the slips is connected to the push rod, the upper end of the push rod is connected to the support sleeve, and the upper end of the support sleeve is connected to the hydraulic cylinder; the slips and the push rod are a group, and at least three groups are provided.

[0033] Furthermore, the straightening mechanism is positioned by a first limiting ring; the straightening mechanism includes a straightening shell and a straightening block, the straightening shell is sleeved on the first limiting ring, a straightening groove is provided on the straightening shell above the first limiting ring, a straightening block is provided in the straightening groove, and a spring is provided at the radial bottom of the straightening block to keep the straightening block in an ejected state.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. It can be connected back multiple times, the docking column can be replaced according to needs, and the docking efficiency is high.

[0036] 2. The innovative hydraulic liner hanger is used. After the sealing plug is inserted into the tie-back barrel, the pressure difference is 70MPa, which is 20MPa higher than the 50MPa pressure difference of conventional side drilling, meeting the 70MPa pressure difference requirement of fracturing construction.

[0037] 3. The oil return pipe realizes the separation of oil and casing, effectively protecting the old wellbore casing.

[0038] 4. Achieve maximum diameter fracturing of small wells, capable of meeting the maximum displacement of 10m 3 / min fracturing construction, compared with the common fracturing methods, the maximum construction displacement is 4-5m 3 / min, construction displacement increased by 3-4m 3 / min. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic structural diagram of a side drilling well fracturing pressure-bearing tubing string of the utility model;

[0040] Figure 2 This is a schematic structural diagram of the hydraulic liner hanger in the utility model;

[0041] Figure 3 It is a schematic diagram of the connection structure of the anchor sealing plug and the return socket in the utility model.

[0042] Figure: 11, tie-back tubing; 12, sealing spigot; 13, tie-back sleeve; 14, liner hanger; 15, hydraulic loading pipe; 16, liner hanger for sidetracking; 12.1, anchor seal plug; 12.2, seal ring assembly; 13.1, tie-back socket; 13.2, asymmetric dual-angle thread; A, angle between the upward contact thread surface and the upward direction; B, angle between the downward contact thread surface and the downward direction;

[0043] 1. Center tube; 1.1. First limiting ring; 1.2. Pressure transmission hole; 1.3. Second limiting ring; 2.1. Righting block; 2.2. Righting shell; 3. Limit pin; 4. Hydraulic cylinder; 4.1. Pressure ring; 4.2. Starting shear pin; 5. Support sleeve; 6. Push rod; 7. Slip; 8. Cone sleeve. DETAILED DESCRIPTION

[0044] 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 embodiments described 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 making creative efforts are within the scope of protection of the present invention.

[0045] Example 1:

[0046] See also Figures 1 to 3 The utility model provides a side drilling well fracturing pressure-bearing tubing string, including a tail pipe hanging string and a plug-in pipe string. The tail pipe hanging string includes a return pipe 13, a hydraulic tail pipe hanging device, and a tail pipe connected in sequence from top to bottom. The plug-in pipe string includes a return oil pipe 11 and a sealing plug-in pipe 12 connected in sequence from top to bottom. A return socket 13.1 is provided at the upper end of the return pipe 13, and an anchoring sealing plug 12.1 is provided at the lower end of the sealing plug-in pipe 12. The anchoring sealing plug 12.1 is a petal structure. The anchoring sealing plug 12.1 is connected to the return socket 13.1 through a return thread, and the return thread is provided with an asymmetric double-angle thread 13.2.

[0047] The tail pipe is a side drilling section suspension tail pipe 16, the upper end of the return oil pipe 11 is connected to the wellhead, and the fracturing fluid enters the side drilling slim hole formation from the side drilling section suspension tail pipe 16.

[0048] Furthermore, the asymmetric double-angle thread 13.2 includes an upward-lifting contact tooth surface and a downward-lifting contact tooth surface. The angle A between the upward-lifting contact tooth surface and the upward-lifting direction is 45°-70°, and the angle B between the downward-lifting contact tooth surface and the downward-lifting direction is 20°-30°, so that the plug-in pipe column can be quickly plugged in downward and can be released by applying force to lift it up.

[0049] Preferably, a transition surface is provided between the upward contact tooth surface and the downward contact tooth surface to enhance the strength of the asymmetric double-angle thread tooth 13.2 and improve the load capacity.

[0050] Specifically, the anchoring sealing plug 12.1 is divided into six petals, and the petal structure enables the anchoring sealing plug 12.1 to have deformation ability, so as to achieve rapid downward plugging and upward lifting to release the connection.

[0051] Specifically, the return socket 13.1 is provided with an internal return thread, and the anchoring sealing plug 12.1 is provided with an external return thread.

[0052] Specifically, the return socket 13.1 is provided with a sealing section above the internal return thread, and the outer wall of the anchor sealing plug 12.1 is fixedly provided with a sealing ring assembly 12.2 above the external return thread, and the sealing ring assembly 12.2 can contact and seal with the sealing section.

[0053] Specifically, the tie-back thread is a reverse thread, and the thread can be easily disconnected by rotating the pipe column forward. The petal structure and the asymmetric double-angle thread teeth 13.2 can disengage the thread by lifting the pipe column.

[0054] Furthermore, the hydraulic tail tube suspension device includes a tail tube hanger 14 and a hydraulic loading pipe 15; the tail tube hanger 14 includes a center tube 1, the outer wall of the center tube 1 is sleeved with a straightening mechanism, a hydraulic drive mechanism, and a suspension anchoring mechanism from top to bottom, the outer wall of the center tube 1 is provided with a first limiting ring 1.1 and a second limiting ring 1.3 from top to bottom, the outer wall of the lower end of the center tube 1 is threadedly connected with a cone sleeve 8, the straightening mechanism is positioned by the first limiting ring 1.1, the hydraulic drive mechanism includes a hydraulic cylinder 4, the hydraulic cylinder 4 is provided with a limiting pin 3, a pressure ring 4.1, and a starting shear pin 4.2, the limiting pin 3 is located between the first limiting ring 1.1 and the second limiting ring 1.3, the pressure ring 4.1 is located below the second limiting ring 1.3, the starting shear pin 4.2 radially penetrates the pressure ring 4.1 and is embedded in the center tube 1, the center tube 1 is at A pressure transmission hole 1.2 is set between the second limiting ring 1.3 and the pressure ring 4.1, and the pressure ring 4.1 contacts the outer wall of the center tube 1 and is sealed. The second limiting ring 1.3 contacts the inner wall of the hydraulic cylinder 4 and is sealed. The suspension anchoring mechanism includes a slip 7, which is connected to the hydraulic cylinder 4. The slip 7 is provided with a conical surface facing the center tube 1, and the upper end of the cone sleeve 8 is provided with a conical surface facing outward. The slip 7 can be pushed out by the cone sleeve 8 when it moves downward, and the outer surface of the slip 7 is provided with slip teeth; a ball seat is fixed in the hydraulic loading pipe 15 by a conductive shear nail; when the hydraulic tail pipe suspension device is in use, the ball seat is first blocked by throwing a ball, and then pressure is applied. The pressure acts on the force ring 4.1 through the pressure transmission hole 1.2. After the starting shear nail 4.2 is cut off, the hydraulic cylinder 4 moves downward, and the slip 7 pushes out the cone sleeve 8 to achieve anchoring, and then pressure is applied to cut the conductive shear nail, and the ball seat is knocked down to achieve conduction.

[0055] Among them, the righting mechanism includes a righting shell 2.2 and a righting block 2.1. The righting shell 2.2 is sleeved on the first limiting ring 1.1. The righting shell 2.2 is provided with a righting groove above the first limiting ring 1.1. The righting block 2.1 is provided in the righting groove. A spring is provided at the radial bottom of the righting block 2.1 to keep the righting block in an ejected state.

[0056] Among them, the upper end of the slip 7 is connected to the push rod 6 by a screw, the upper end of the push rod 6 is connected to the support sleeve 5 by a screw, the upper end of the support sleeve 5 is threadedly connected to the hydraulic cylinder 4, the slip 7 and the push rod 6 are a group, and at least three groups are set; connecting the slip 7 through the push rod 6 can make the slip 7 have better extension and rebound performance.

[0057] Example 2:

[0058] Based on Example 1, this example provides a more specific sidetracking fracturing pressure-bearing string, enabling full-bore, comprehensive fracturing in sidetracking completions using a φ139.7mm original well casing + φ95.3mm liner casing. By threadedly butting and sealing the tieback tube 13 and the sealing spigot 12, instead of using packers and hydraulic anchors, the upper and lower well strings are integrated, preventing the fracturing string from lifting and the hydraulic anchor from damaging the original well casing.

[0059] The tie-back tubing 11 has an outer diameter of φ95.3 mm, an inner diameter of φ82.3 mm, is made of P110 steel, and has a compressive strength of 80.7 MPa. It achieves oil-casing separation and serves to prevent the original wellbore casing from bearing pressure and protect the casing during fracturing construction.

[0060] The anchoring sealing plug 12.1 has an outer diameter of φ101mm, a maximum outer diameter of φ114.3mm, an inner diameter of φ82mm, and is made of steel grade P110. It has a compressive strength of 707MPa. The sealing ring assembly 12.2 of the anchoring sealing plug 12.1 includes two clusters of sealing rubber rings, which are solidified on the steel body of the anchoring sealing plug 12.1 and will not fall off even if damaged by friction. The two clusters of sealing rubber rings are separated by 0.6m, and the pressure difference after sealing is 70MPa, which meets the requirements of fracturing construction.

[0061] The tie-back tube 13 has an outer diameter of φ113mm, an inner diameter of φ100mm, a steel grade of P110, and a compressive strength of 70MPa.

[0062] The hydraulic tail pipe suspension device has an outer diameter of φ115mm, an inner diameter of φ82mm, steel grade P110, and a compressive strength of 70MPa.

[0063] The side drilling section suspension tail pipe 16 has an outer diameter of φ95.3mm, an inner diameter of φ82.3mm, and a steel grade of N80.

[0064] Directions:

[0065] S1. Use the delivery string to lower the liner hanger string into the sidetracked small hole, then drop the ball to pressure the liner hanger 14 to anchor it, and then pressure conduct it, then reverse the buckle and release the string.

[0066] S2. Lower the plug-in pipe string. During the process of slowly lowering the plug-in pipe string, the bottom rubber ring of the anchor sealing plug 12.1 first contacts the return pipe 13. The pump truck will generate pressure when washing the well, indicating that the anchor sealing plug 12.1 has reached the return pipe 13. At this time, the outer return thread of the anchor sealing plug 12.1 has not yet hooked the inner return thread of the return socket 13.1. Continue to lower the anchor sealing plug 12.1 and dock with the return socket 13.1. You can lift it up with a weight exceeding the original 30 tons to verify the docking condition.

[0067] S3. After installing the wellhead, use two 1000-type pump trucks to conduct a positive extrusion test at the maximum displacement to observe whether there is any overflow or gas leakage in the casing annulus, which can verify the sealing performance of the sealing return plug.

[0068] S4. After fracturing is completed, the lifting load can be increased to retract the anchor seal plug 12.1. The buckle can be easily opened by rotating the tubing string forward, and the buckle can be disengaged by lifting the tubing string.

[0069] S5. The production tubing string is lowered and connected to the tie-back socket 13.1 before production can begin.

[0070] It should be noted that the lower ends of the delivery and production tubing strings are both provided with complete external tie-back threads, which can only be unlocked by reverse threading.

[0071] The side drilling fracturing pressure string completely avoids the risk of fracturing string sticking due to the complexity of construction tools and easy sticking of the construction string, while increasing the maximum fracturing operation displacement to 10m 3 / min, achieving full transformation of reservoirs with deep burial depth and poor reservoir properties. The side drilling fracturing pressure string has been successfully used in 10 wells, with a maximum operation pressure of 70MPa and a maximum operation displacement of 10m 3 / min, with a 100% construction success rate. This system has achieved efficient potential development in low-permeability reservoirs, achieving an initial average daily oil production of 6.6 tons per well. Compared to vertical and deviated wells, single-well investment has decreased by over 3 million yuan, and the break-even oil price has dropped by $18.3 per barrel. Investment per million tons of production has decreased by 2.54 billion yuan, and the average single-well profit in the first three years was 1.81 million yuan. This system provides technical support for the next phase of slim-hole casing completion and sidetracking fracturing in the oilfield, generating significant economic and social benefits and possessing high promotion and application value.

[0072] All components not discussed in detail in this application and the connection methods of the components in this application are well-known technologies in the technical field and can be directly applied without further explanation.

[0073] In this utility model, the term "plurality" refers to two or more, unless otherwise specified. Terms such as "installed," "connected," "connected," and "fixed" should be interpreted broadly. For example, "connected" can mean fixed, removable, or integral; "connected" can mean directly or indirectly through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this utility model based on specific circumstances.

[0074] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as "up", "down", "left", "right", "front" and "back" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0075] Throughout this specification, terms such as "one embodiment," "some embodiments," and "specific embodiments" mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A side drilling well fracturing pressure string, comprising a liner hanging string and a plug-in string, wherein the liner hanging string comprises a tie-back tube, a liner hanging device, and a liner connected in sequence from top to bottom, and the plug-in string comprises a tie-back oil pipe and a sealing plug-in tube connected in sequence from top to bottom, wherein a tie-back socket is provided at the upper end of the tie-back tube and an anchor sealing plug is provided at the lower end of the sealing plug-in tube, characterized in that: The anchoring sealing plug is a split-petal structure, and the anchoring sealing plug is connected to the return socket via a return thread; The tie-back thread is provided with asymmetric double-angle thread teeth.

2. The side drilling well fracturing pressure bearing tubing string according to claim 1, characterized in that: The asymmetric dual-angle thread includes an upward contact tooth surface and a downward contact tooth surface; The angle between the lifting contact tooth surface and the lifting direction is 45°-70°; The angle between the lowering contact tooth surface and the lowering direction is 15°-30°.

3. The side drilling well fracturing pressure-bearing tubing string according to claim 2, characterized in that: A transition surface is provided between the upward-lifting contact tooth surface and the downward-lifting contact tooth surface.

4. The side drilling well fracturing pressure bearing tubing string according to claim 1, characterized in that: The return socket is provided with an internal return thread, and the anchor sealing plug is provided with an external return thread.

5. The side drilling well fracturing pressure bearing tubing string according to claim 4, characterized in that: The return socket is provided with a sealing section above the internal return thread, and the outer wall of the anchor sealing plug is fixedly provided with a sealing ring group above the external return thread, and the sealing ring group can contact and seal with the sealing section.

6. The side drilling well fracturing pressure-bearing tubing string according to any one of claims 1 to 5, characterized in that: The tie-back thread is a reverse thread.

7. The side drilling well fracturing pressure bearing tubing string according to claim 1, characterized in that: The liner suspension device is a hydraulic liner suspension device, which includes a liner hanger and a hydraulic loading pipe connected in sequence from top to bottom; The liner hanger comprises a central tube, the outer wall of which is sheathed from top to bottom with a straightening mechanism, a hydraulic drive mechanism, and a suspension anchoring mechanism; A ball seat is fixed in the hydraulic loading pipe via conductive shear nails.

8. The side drilling well fracturing pressure bearing tubing string according to claim 7, characterized in that: The outer wall of the central tube is provided with a first limiting ring and a second limiting ring from top to bottom; The hydraulic drive mechanism includes a hydraulic cylinder, which is provided with a limit pin, a pressure ring, and a start shear pin; the limit pin is located between the first limit ring and the second limit ring, the pressure ring is located below the second limit ring, and the start shear pin radially penetrates the pressure ring and is embedded in the center tube; The central tube is provided with a pressure transmission hole between the second limiting ring and the pressure ring. The pressure ring contacts the outer wall of the central tube and is sealed. The second limiting ring contacts the inner wall of the hydraulic cylinder and is sealed.

9. The side drilling well fracturing pressure bearing tubing string according to claim 8, characterized in that: The outer wall of the lower end of the central tube is connected with a cone sleeve; The suspension anchoring mechanism includes a slip, which is connected to a hydraulic cylinder. The slip is provided with a conical surface facing inwards of the central tube, and the upper end of the cone sleeve is provided with a conical surface facing outwards. The slip can be pushed out by the cone sleeve when it moves downwards, and the outer surface of the slip is provided with slip teeth; The upper end of the slip is connected to the push rod, the upper end of the push rod is connected to the support sleeve, and the upper end of the support sleeve is connected to the hydraulic cylinder; the slips and the push rod are a group, and at least three groups are provided.

10. The side drilling well fracturing pressure bearing tubing string according to claim 8, characterized in that: The straightening mechanism is positioned by a first limiting ring; the straightening mechanism includes a straightening shell and a straightening block, the straightening shell is sleeved on the first limiting ring, a straightening groove is provided on the straightening shell above the first limiting ring, a straightening block is provided in the straightening groove, and a spring is provided at the radial bottom of the straightening block to keep the straightening block in an ejected state.

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