Resin anti-leakage device for shaft reconstruction and shaft reconstruction equipment and method

Abstract

According to the resin anti-leakage device for shaft reconstruction and the shaft reconstruction equipment and method, in the device, a hydraulic cylinder shell is connected with a conversion connector and arranged on a central pipe in a sleeving mode so that a cavity can be formed between the hydraulic cylinder shell and the central pipe, a piston is movably arranged in the cavity, and a liquid channel penetrates through the central pipe so that an upper connector and the cavity can be communicated; the liquid channel is located on the side, away from the piston, of the piston sealing ring, liquid from the upper connector enters the cavity through the liquid channel to push the piston to move, the center pipe is movably sleeved with the retaining seat, the retaining seat moves along with the piston, and the retaining ring is connected with the retaining seat in a sawtooth mode to form a sawtooth retaining structure. The coupling is arranged on the central pipe in a sleeving mode, the upper end of the coupling abuts against the rubber barrel, the lower end of the coupling is connected with the coupling, the rubber barrel pressing sleeve extrudes the rubber barrel under the thrust of the piston, the rubber barrel and the distance ring move downwards, and the rubber barrel is extruded and deformed under blocking of the coupling to block the casing annulus. The device solves the problem of leakage during resin well cementation and improves the well cementation efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of workover, and particularly to a resin anti-leakage device for wellbore reconstruction, a wellbore reconstruction device and a method. Background Art

[0002] In order to tap the potential of remaining reservoirs, improve the oil recovery rate of oilfields, reduce the drilling operation cost, and lower the comprehensive development cost, for low-yield horizontal wells in low-permeability blocks, aiming at volume fracturing, a large-displacement double-packer single-slip sectional fracturing technology integrating "comprehensive energy supplement, dynamic temporary plugging, and synchronous fracturing" has been formed. However, there are problems such as long construction period and high construction operation cost. In order to improve the fracturing efficiency, shorten the construction period, reduce the construction cost, and meet the requirements of the repeated and efficient sectional fracturing technology for horizontal wells, research on the post-bridge-perforation joint repeated fracturing tool and technology after large-size full-bore wellbore reconstruction has been carried out.

[0003] In the existing technology of wellbore reconstruction, due to the too small annular space between the new and old casings during cementing, in order to ensure that the strength of the cementing fluid can meet the requirements of fracturing construction, high-strength and high-toughness saturated resin is used for cementing. For the leakage or continuous fluid ejection from the formation during resin cementing, currently, mainly shut-in waiting for setting is adopted, but the effect is poor, and the subsequent drill plugging takes time and poses a hidden danger to the back connection seal. The main problems and difficulties in the current wellbore reconstruction and cementing process are as follows:

[0004] (1) The cementing displacement pressure is high, and there is leakage in the low-pressure area. During well flushing, the resin in the annulus at the top of the hanger continues to sink and leak, and the cementing quality does not meet the standard.

[0005] (2) After cementing, the formation continuously overflows, and the return volume is greater than the displacement volume. When shutting in, the annulus is damaged before the resin solidifies.

[0006] (3) After the resin setting, the pressure test fails to meet the requirements, and cement squeezing is required for reinforcement.

[0007] (4) Cementing void sections often appear below the annulus near the hanger.

[0008] (5) After the setting, wellbore reaming requires drill plugging to reach the artificial bottom hole.

[0009] The above information disclosed in the background art is only used to enhance the understanding of the background of the present invention, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0010] The purpose of the present invention is to provide a resin anti-leakage device for wellbore reconstruction, a wellbore reconstruction device and a method, which solve the problem that the resin leakage during wellbore reconstruction and cementing leads to unqualified resin annulus pressure test, solve the problem of overflow during resin cementing, meet the requirements of fracturing cementing quality, improve the resin cementing efficiency, solve the problem of a large amount of drill plugging during wellbore reaming, and provide a good back connection cylinder state for back insertion.

[0011] To achieve the above object, the present invention provides the following technical solutions:

[0012] A resin anti-loss device for wellbore reconstruction according to the present invention includes:

[0013] An upper sub, which is of a hollow structure,

[0014] A swivel sub, which is of a hollow structure and is connected to the upper sub;

[0015] A central pipe, which is connected to the swivel sub;

[0016] A cylinder housing, which is connected to the swivel sub and sleeved on the central pipe to form a cavity between the cylinder housing and the central pipe;

[0017] A piston, which is movably arranged in the cavity,

[0018] A piston seal ring, which is arranged on the top of the piston,

[0019] A liquid channel, which penetrates through the central pipe to communicate the upper sub and the cavity. The liquid channel is located on the side of the piston seal ring away from the piston. The liquid from the upper sub enters the cavity through the liquid channel to push the piston to move,

[0020] A backstop seat, which is movably sleeved on the central pipe. The backstop seat moves with the piston. A backstop ring is serratedly connected to the backstop seat to form a serrated backstop structure. The backstop ring moves with the backstop seat;

[0021] A rubber barrel compression sleeve, which is connected to the backstop seat and movably sleeved on the central pipe,

[0022] A rubber barrel, which is sleeved on the central pipe and abuts against the rubber barrel compression sleeve,

[0023] At least one spacer ring, which is tightly fastened to the rubber barrel,

[0024] A lower sub, which is connected to the bottom end of the central pipe,

[0025] A coupling, which is sleeved on the central pipe. The upper end of the coupling abuts against the rubber barrel and the lower end is connected to the coupling. The rubber barrel compression sleeve extrudes the rubber barrel under the thrust of the piston. The rubber barrel and the spacer ring move downward. Under the block of the coupling, the rubber barrel is extruded and deformed to block the casing annulus.

[0026] In the resin anti-loss device for wellbore reconstruction, a shear pin for limiting the backstop seat is further included. The piston moves downward to shear the shear pin.

[0027] In the resin anti-loss device for wellbore reconstruction, the upper sub is detachably connected to the casing at the bottom of the hanger.

[0028] In the described resin anti - leakage device for wellbore reconstruction, the upper joint is a hollow casing, which is thread - connected to the casing at the bottom of the hanger.

[0029] In the described resin anti - leakage device for wellbore reconstruction, the piston seal ring includes fluororubber.

[0030] In the described resin anti - leakage device for wellbore reconstruction, the piston is provided with an outer piston groove for installing the piston seal ring.

[0031] In the described resin anti - leakage device for wellbore reconstruction, the lower joint is thread - connected to the central pipe, and the collar is thread - connected to the lower joint and is provided with a pin for locking and preventing rotation.

[0032] A wellbore reconstruction device includes

[0033] A first casing, which is connected to the wellbore

[0034] A tie - back casing, which is arranged in the wellbore

[0035] An insert head, which is connected to the tie - back casing

[0036] A hanger, which is connected to the insert head

[0037] A second casing, which is connected to the hanger and extends within the first casing

[0038] The described resin anti - leakage device for wellbore reconstruction, which is connected to the second casing

[0039] A bump - pressure ball seat, which is connected to the second casing and extends within the first casing

[0040] At least one float collar, which is connected to the second casing

[0041] A guide shoe, which is connected to the bottom end of the second casing.

[0042] In the described wellbore reconstruction device, the hanger is a retrievable hanger, and the first float collar and the second float collar are sequentially arranged between the bump - pressure ball seat and the guide shoe.

[0043] A reconstruction method of a wellbore reconstruction device includes

[0044] The first casing is connected to the wellbore, the tie - back casing is sleeved in the wellbore, the insert head is connected to the tie - back casing, and the hanger is connected to the insert head.

[0045] The resin anti - leakage device for wellbore reconstruction is connected to the bottom of the hanger and is lowered into the well with the second casing. After the hanger is released, the cementing operation is carried out.

[0046] When all cementing resin is pumped into the wellbore, the drill pipe rubber plug is put in and then replaced with clean water. When the drill pipe rubber plug moves down to the impact pressure ball seat and the impact pressure reaches the preset pressure, the cementing displacement is completed. The piston of the resin anti-leakage device moves down under the push of the hydraulic pressure, the shear pin is cut off, the stop ring moves down while the rubber sleeve is compressed, the rubber sleeve and the spacer ring move down as a whole, and the rubber sleeve is squeezed and deformed under the obstruction of the coupling to seal the annulus of the second casing. The piston moves down until the rubber sleeve expands to a preset degree and stops, and continues to displace to the preset pressure and the preset time for stabilizing the pressure to ensure that the sealing of the resin anti-leakage device is effective.

[0047] Release the pressure, lift up the center pipe, and clean the excess cementing resin on the top of the hanger.

[0048] In the above technical scheme, the resin leakage prevention device, wellbore reconstruction equipment and method provided by the present invention have the following beneficial effects: the resin leakage prevention device for wellbore reconstruction effectively prevents the problem of resin leakage in cementing and the occurrence of formation fluid spitting after cementing, thereby improving the cementing quality, avoiding the subsequent remedial measures such as squeezing cementing fluid, reducing the influence of formation leakage on the quality of resin cementing, improving the strength of the resin ring in the narrow gap casing annulus, and no longer having a cementing empty section in the annulus between the hanger and the old casing; after the solidification is completed, it is no longer necessary to drill resin to pass the well to the bottom of the artificial well; providing a tie-back tube in good condition to ensure the reliability of the tie-back seal. Improve construction efficiency and shorten the construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present application 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 recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0050] Figure 1 A schematic structural diagram of a resin anti-loss device for wellbore reconstruction in a lowered state provided by an embodiment of the present invention.

[0051] Figure 2 A structural schematic diagram of the working state of a resin anti-loss device for wellbore reconstruction provided by one embodiment of the present invention.

[0052] Figure 3 A schematic structural diagram of a wellbore reconstruction device with a resin anti-loss device for wellbore reconstruction provided in accordance with another embodiment of the present invention. DETAILED DESCRIPTION

[0053] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0054] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0055] It should be noted that like reference numerals and letters denote like items in the following figures, and thus, once an item is defined in one figure, it does not require further definition and explanation in subsequent figures.

[0056] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0057] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0058] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed broadly. For example, it may be a fixed connection, a detachable connection, or integrated; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] In the present invention, unless otherwise clearly specified and defined, the first feature being “above” or “below” the second feature may include direct contact between the first and second features, or may include the first and second features not being in direct contact but being in contact through additional features therebetween. Moreover, the first feature being “above”, “over” and “on top of” the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being “below”, “beneath” and “underneath” the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the horizontal height of the first feature is less than that of the second feature.

[0060] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0061] See Figure 1-2 As shown, in one embodiment, a resin leak prevention device for wellbore reconstruction according to the present invention includes

[0062] an upper sub 1, which is of a hollow structure

[0063] a swivel sub 2, which is of a hollow structure and is connected to the upper sub 1;

[0064] a central pipe 3, which is connected to the swivel sub 2;

[0065] a cylinder housing, which is connected to the swivel sub 2 and sleeved on the central pipe 3 to form a cavity between the cylinder housing and the central pipe 3;

[0066] a piston 5, which is movably arranged in the cavity

[0067] a piston seal ring 4, which is arranged on the top of the piston 5

[0068] a liquid passage, which penetrates through the central pipe 3 to communicate the upper sub 1 and the cavity. The liquid passage is located on the side of the piston seal ring 4 away from the piston 5. Liquid from the upper sub 1 enters the cavity through the liquid passage to push the piston 5 to move.

[0069] a backstop seat 7, which is movably sleeved on the central pipe 3. The backstop seat 7 moves along with the piston 5. A backstop ring 8 is serratedly connected to the backstop seat 7 to form a serrated backstop structure. The backstop ring 8 moves along with the backstop seat 7;

[0070] a rubber barrel press sleeve 9, which is connected to the backstop seat 7 and movably sleeved on the central pipe 3

[0071] a rubber barrel 10, which is sleeved on the central pipe 3 and abuts against the rubber barrel press sleeve 9

[0072] At least one spacer ring 11, which is tightly sleeved on the rubber cylinder 10,

[0073] The lower sub 13, which is connected to the bottom end of the central pipe 3,

[0074] The collar 12, which is sleeved on the central pipe 3, with its upper end abutting against the rubber cylinder 10 and its lower end connected to the collar 12. The rubber cylinder pressing sleeve 9 squeezes the rubber cylinder 10 under the thrust of the piston 5. The rubber cylinder 10 and the spacer ring 11 move downward, and the rubber cylinder 10 is squeezed and deformed to block the casing annulus under the block of the collar 12.

[0075] The resin leak - off prevention device for wellbore reconstruction takes into account the extrusion limitation of the annulus clearance on the rubber cylinder and the starting pressure of the hydraulic cylinder. At the same time, it also considers the internal pressure resistance of the tool. It can not only meet the function that the rubber cylinder completes the extrusion seal at the end of cementing bump pressure, but also achieve the design goal that the pipe string is not affected by multiple staged fracturing and the overall pipe string compressive strength, and can better achieve the construction purpose of repeated fracturing in old well reconstruction.

[0076] In the preferred embodiment of the resin leak - off prevention device for wellbore reconstruction, it further includes a shear pin 6 for limiting and preventing the retreat of the seat 7. The piston 5 moves downward to cut the shear pin 6.

[0077] In the preferred embodiment of the resin leak - off prevention device for wellbore reconstruction, the upper sub 1 is detachably connected to the casing at the bottom of the hanger 16.

[0078] In the preferred embodiment of the resin leak - off prevention device for wellbore reconstruction, the upper sub 1 is a hollow casing, which is thread - connected to the casing at the bottom of the hanger 16.

[0079] In the preferred embodiment of the resin leak - off prevention device for wellbore reconstruction, the piston seal ring 4 includes fluororubber.

[0080] In the preferred embodiment of the resin leak - off prevention device for wellbore reconstruction, the piston 5 is provided with a piston outer groove for installing the piston seal ring 4.

[0081] In the preferred embodiment of the resin leak - off prevention device for wellbore reconstruction, the lower sub 13 is thread - connected to the central pipe 3, and the collar 12 is thread - connected to the lower sub 13 and is provided with a pin for locking and preventing rotation.

[0082] In one embodiment, the upper sub 1 is machined from P110 grade casing, with oil casing threads machined on the upper part, which is connected to the casing threads at the bottom of the hanger 16. At the same time, it has the functions of sealing, tensile (compressive) resistance. The adapter sub 2 is made of P110 pipe material, with the same casing connection type as the upper part of the upper sub 1, and the lower connection thread is specially made of high-strength tensile and internal pressure-resistant non-standard threads to ensure the strength of the pipe string. The central tube 3 is machined from 42CrMo material, and the upper and lower joints 13 are non-standard special joints respectively. There are liquid channels on the tube body to facilitate the downward movement of the piston 5. The piston seal ring 4 is made of fluororubber and is placed on the outer groove of the piston. As the liquid enters, the liquid cylinder moves downward to cut the shear pin 6.

[0083] In one embodiment, as the piston 5 continues to move downward, the back-off seat 7 pushes the back-off ring 8 to move. The pin between the back-off seat 7 and the back-off ring 8 prevents the possible rotation of the back-off ring 8. As the piston 5 moves downward, the rubber barrel bushing 9 begins to squeeze the rubber barrel 10 under the thrust of the piston 5. The rubber barrel 10 and the spacer ring 11 move downward, and the rubber barrel 10 is squeezed and deformed under the block of the collar 12 to seal the casing annulus. The collar 12 and the lower sub 13 are connected by threads and locked by pins to prevent rotation. The collar 12 is machined from P110 steel material. The lower sub 13 is machined from 42CrMo material to ensure the strength of the pipe material. The upper end is connected to the central tube 3 by non-standard casing threads, and the lower end is machined with oil casing threads and connected to the inserted casing.

[0084] A wellbore reconstruction device includes,

[0085] A first casing 17, which is connected to the wellbore,

[0086] A tieback casing 14, which is arranged in the wellbore,

[0087] An insert head 15, which is connected to the tieback casing 14,

[0088] A hanger 16, which is connected to the insert head 15,

[0089] A second casing 18, which is connected to the hanger 16 and extends within the first casing 17,

[0090] The resin leak-off device for wellbore reconstruction, which is connected to the second casing 18,

[0091] A bump pressure ball seat 19, which is connected to the second casing 18 and extends within the first casing 17,

[0092] At least one float collar, which is connected to the second casing 18,

[0093] A guide shoe 22, which is connected to the bottom end of the second casing 18.

[0094] In a preferred embodiment of the described wellbore reconstruction device, the hanger 16 is a retrievable hanger 16, and the first float collar 20 and the second float collar 21 are successively arranged between the bumping ball seat 19 and the guide shoe 22.

[0095] In one embodiment, the wellbore reconstruction device completes the new wellbore at the bottom by cementing the completion string with a retrievable hanger 16, and then reconnects the casing 14 to complete the reconstruction of the upper casing wellbore, thereby completing the reconstruction of the entire wellbore to meet the wellbore conditions for refracturing of old wells. During the reconstruction process of the bottom wellbore, the cementing quality is often unqualified due to cementing leakage and formation fluid backflow, resulting in unqualified resin ring pressure testing. A resin leak prevention device is connected to the bottom of the hanger 16. After the bumping is completed, the annulus is directly sealed to make the annulus a closed space, which can not only improve the leakage of the resin in the annulus after cementing, but also prevent the formation fluid from backflowing and damaging the resin ring after displacement.

[0096] The reconstruction method of the wellbore reconstruction device includes,

[0097] The first casing 17 is connected to the wellbore, sleeved and reconnected inside the wellbore. The insert head 15 is connected to the reconnected casing 14, and the hanger 16 is connected to the insert head 15.

[0098] The resin leak prevention device for wellbore reconstruction is connected to the bottom of the hanger 16 and is lowered into the well with the second casing 18. After the hanger 16 is released, the cementing operation is carried out.

[0099] When all the cementing resin is pumped into the wellbore, a drill pipe plug is inserted and then displaced with clean water. When the drill pipe plug descends to the bumping ball seat 19 and the bumping reaches the predetermined pressure, the cementing displacement ends. The piston 5 of the resin leak prevention device descends under the hydraulic pressure, the shear pin 6 is cut off, the anti-backflow ring 8 descends while the rubber barrel compression sleeve 9 descends and compresses. The rubber barrel 10 and the spacer ring 11 descend as a whole. Under the block of the collar 12, the rubber barrel 10 is extruded and deformed to seal the annulus of the second casing 18. The piston 5 descends until the rubber barrel 10 expands to the predetermined degree and stops. Continue to displace to the predetermined pressure and stabilize for the predetermined time to ensure the effective sealing of the resin leak prevention device.

[0100] Release the pressure, lift the central pipe 3, and clean the excess cementing resin on the top of the hanger 16.

[0101] In one embodiment, the method includes,

[0102] The tool is connected to the bottom of the hanger 16 and is lowered into the well with the pipe string.

[0103] After circulation and the hanger 16 is released, the cementing operation is carried out.

[0104] When all the cementing resin is pumped into the wellbore, a drill pipe plug is inserted and then displaced with clean water.

[0105] When the composite rubber plug descends to the bumping seat and the bumping pressure reaches 30 Mpa, the cementing displacement ends. Under the push of the hydraulic pressure, the piston 5 of the resin anti-leakage device descends, the shear pin 6 is cut off, the backstop ring 8 descends, and at the same time the rubber cylinder bushing 9 descends to compress the rubber cylinder 10 and the spacer ring 11 as a whole. Since the collar 12 is fixed, when the piston 5 descends to a certain extent where the rubber cylinder 10 expands, it will be prohibited. Continue to displace to 35 Mpa and stabilize the pressure for 3 minutes to ensure the effective sealing of the resin anti-leakage device.

[0106] Release the pressure and lift the central pipe 3 to clean the excess cementing resin on the top of the hanger 16.

[0107] Finally, it should be noted that the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0108] Only some exemplary embodiments of the present invention have been described by way of illustration above. Undoubtedly, for those of ordinary skill in the art, the described embodiments can be modified in various different ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A resin leak prevention device for wellbore reconstruction, characterized in that, it includes, an upper sub, which is of a hollow structure, a swivel sub, which is of a hollow structure and connects to the upper sub; a central tube, which connects to the swivel sub; a cylinder housing, which connects to the swivel sub and sleeves the central tube to form a cavity between the cylinder housing and the central tube; a piston, which is movably arranged in the cavity, a piston seal ring, which is arranged on the top of the piston, a liquid passage, which penetrates through the central tube to connect the upper sub and the cavity, and the liquid passage is located on the side of the piston seal ring away from the piston, and the liquid from the upper sub enters the cavity through the liquid passage to push the piston to move, a backstop seat, which is movably sleeved on the central tube, and the backstop seat moves with the piston, and a backstop ring is serratedly connected to the backstop seat to form a serrated backstop structure, and the backstop ring moves with the backstop seat; a rubber barrel press sleeve, which connects to the backstop seat and is movably sleeved on the central tube, a rubber barrel, which sleeves the central tube and abuts against the rubber barrel press sleeve, at least one spacer ring, which is tightly fastened to the rubber barrel, a lower sub, which connects to the bottom end of the central tube, a coupling, which sleeves the central tube and its upper end abuts against the rubber barrel and its lower end connects to the coupling, and the rubber barrel press sleeve squeezes the rubber barrel under the thrust of the piston, and the rubber barrel and the spacer ring move downward, and the rubber barrel is squeezed and deformed under the block of the coupling to seal the casing annulus.

2. A resin leak prevention device for wellbore reconstruction according to claim 1, characterized in that, it further includes a shear pin for limiting the backstop seat, and the piston moves downward to shear the shear pin.

3. A resin leak prevention device for wellbore reconstruction according to claim 1, characterized in that, the upper sub is detachably connected to the casing at the bottom of the hanger.

4. A resin leak prevention device for wellbore reconstruction according to claim 1, characterized in that, the upper sub is a hollow casing, which is threadedly connected to the casing at the bottom of the hanger.

5. A resin leak prevention device for wellbore reconstruction according to claim 1, characterized in that, the piston seal ring includes fluororubber.

6. A resin leak prevention device for wellbore reconstruction according to claim 1, characterized in that, the piston is provided with a piston outer groove for installing the piston seal ring.

7. A resin leak prevention device for wellbore reconstruction according to claim 1, characterized in that, the lower sub is threadedly connected to the central tube, and the coupling is threadedly connected to the lower sub and is provided with a pin for locking and anti-rotation.

8. A wellbore reconstruction device, characterized in that, it includes, a first casing, which is connected to the wellbore, a tieback casing, which is arranged in the wellbore, an insert head, which is connected to the tieback casing, a hanger, which is connected to the insert head, a second casing, which is connected to the hanger and extends in the first casing, a resin leak prevention device for wellbore reconstruction according to any one of claims 1-7, which is connected to the second casing, a bump pressure seat, which is connected to the second casing and extends in the first casing, at least one float collar, which is connected to the second casing, a guide shoe, which is connected to the bottom end of the second casing.

9. A wellbore reconstruction device according to claim 8, It is characterized in that the hanger is a retrievable hanger, and the first float collar and the second float collar are sequentially arranged between the bumping ball seat and the guide shoe.

10. A reconstruction method of a wellbore reconstruction device according to claim 8 or 9, It is characterized in that it includes the first casing is connected to the wellbore, the retrievable sleeve is sleeved in the wellbore, the insert head is connected to the retrievable casing, the hanger is connected to the insert head, the resin leak prevention device for wellbore reconstruction is connected to the bottom of the hanger and is lowered into the well with the second casing. After the hanger is released, the cementing operation is carried out. When all the cementing resin is pumped into the wellbore, a drill pipe plug is put in and then displaced with clean water. When the drill pipe plug descends to the bumping ball seat and the bumping reaches the predetermined pressure, the cementing displacement ends. The piston of the resin leak prevention device descends under the hydraulic pressure, the shear pin is cut off, the backstop ring descends while the rubber barrel compression sleeve descends and compresses, and the rubber barrel and the spacer ring descend as a whole. Under the block of the collar, the rubber barrel is extruded and deformed to seal the annulus of the second casing. The piston descends until the rubber barrel expands to the predetermined degree and stops. Continue to displace to the predetermined pressure and stabilize for the predetermined time to ensure the effective sealing of the resin leak prevention device. Release the pressure, lift the central pipe, and clean the excess cementing resin on the top of the hanger.

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