Double-clamping single-cylinder bridge plug capable of preventing setting deviation and assembling method of double-clamping single-cylinder bridge plug

Abstract

The invention relates to a double-clamping single-cylinder bridge plug capable of preventing setting deviation and an assembling method thereof. The double-clamping single-cylinder bridge plug comprises a center pipe and a releasing head, two clamping and sealing assemblies are arranged between the center pipe and the releasing head and comprise the upper clamping and sealing assembly and the lower clamping and sealing assembly, the upper clamping and sealing assembly comprises an upper slip and an upper cone, the thick end of the upper cone faces downwards, and the upper slip is arranged outside the upper cone in a sleeving mode; the lower clamping and sealing assembly comprises a lower slip and a lower cone, the thick end of the lower cone faces upwards, and the lower slip is arranged outside the lower cone in a sleeving mode. The upper slip and the lower slip are respectively provided with a plurality of slip petals, separation grooves are arranged among the plurality of slip petals, and openings of the separation grooves respectively face the upper cone and the lower cone; and a lateral guide piece is arranged in the separation groove. According to the invention, not only can non-uniform spalling occurring in the slip expansion process be solved, but also the flowback efficiency is higher and the flowback effect is more effective.

Description

Technical Field

[0001] The present application relates to a double-card single-tube bridge plug for preventing setting deviation and an assembly method thereof, and is applicable to the technical field of downhole plugging tools. Background Art

[0002] At present, the bridge plugs used in major oil and gas fields must be successfully sealed to ensure the normal progress of subsequent fracturing work, and the return fluid work will be carried out after the construction is completed. The smooth sealing of the bridge plug and the return fluid work are important links in oil and gas production. Whether it is successful or not will directly affect the progress of production. Therefore, adjusting and optimizing the bridge plug structure, ensuring the stability of the bridge plug, and improving the efficiency of the return fluid are of great significance to oil and gas production. The existing technology has the following disadvantages: the sealing slips expand unevenly, the anchoring force is insufficient, and it cannot withstand the high-pressure working environment.

[0003] On the one hand, the function of the conventional release head is to connect the center pipe, fix the various bridge plug components located on the center pipe, and use the thread at the center hole of the release head to cooperate with the sealing rod to provide the sealing force. Among them, the slips mainly expand the slip petals of the slips gradually in the process of moving from small diameter to large diameter on the conical surface of the cone. Each slip will have a high probability of uneven expansion and cracking. The slip petals that are not evenly expanded will also have a high probability of continuing to be in an uneven expansion state during the subsequent movement until they are close to the inner wall of the casing. In this state, the slip sealing will deviate and it will be difficult to withstand the high-pressure working environment underground, resulting in backward slippage during the pressure injection of the bridge plug, unqualified pressure drop, and in severe cases, the bridge plug may directly slip and fall into the ground, seriously affecting the construction progress and causing high construction costs.

[0004] On the other hand, the discharge of conventional bridge plug return fluid is mainly carried out through the diameter in the middle of the release head for return fluid operation. Therefore, the main factor affecting the return fluid efficiency is determined by the diameter of the bridge plug, but the inner diameter of the release head is restricted by many other working parameters and cannot be adjusted. For example: the sealing force, the larger the normal diameter, the larger the diameter of the release thread, the greater the release force, which is not conducive to downhole work; the casing diameter, when the bridge plug is designed, the diameter of the bridge plug itself is affected by the specifications of the commonly used oil casing, and is proportional to the specifications of the oil casing. Therefore, when the outer diameter is determined, the increase in the inner diameter will also be limited. In summary, optimizing the diameter is not an effective way to increase the return efficiency. The cost of the return fluid process is high. The reason is that there is generally no structural design to improve the return fluid, which makes the return fluid efficiency low. Summary of the invention

[0005] The purpose of the present application is to design a double-clip single-tube bridge plug and an assembly method thereof for preventing the setting from being offset, which can not only solve the uneven expansion and cracking that occurs during the expansion of the slips, but also make the return efficiency higher and more effective.

[0006] A double-card single-tube bridge plug for preventing setting deviation according to the present application includes a center tube and a release head, the lower end of the center tube is connected to the release head, and an upper slip connection part is provided on the side of the center tube away from the release head; two groups of card sealing components are provided between the center tube and the release head, and a rubber cylinder is provided between the two groups of card sealing components, the two groups of card sealing components include an upper card sealing component and a lower card sealing component, the upper card sealing component is arranged between the upper slip connection part and the rubber cylinder, and the lower card sealing component is arranged on the rubber cylinder and the throwing hand head; the upper sealing assembly includes an upper slip and an upper cone, the thick end of the upper cone faces downward, and the upper slip is sleeved on the outside of the upper cone; the lower sealing assembly includes a lower slip and a lower cone, the thick end of the lower cone faces upward, and the lower slip is sleeved on the outside of the lower cone; the upper slip and the lower slip are respectively provided with a plurality of slip petals, and separation grooves are provided between the plurality of slip petals, and the openings of the separation grooves are respectively facing the upper cone and the lower cone; lateral guides are provided in the separation grooves.

[0007] Wherein, an upper protective bowl and a lower protective bowl may be respectively provided on both sides of the rubber cylinder, the upper cava and the upper cone may be arranged between the upper cava connecting part and the upper protective bowl, and the lower cava and the lower cone may be arranged between the lower protective bowl and the drop head; the upper clamping assembly and the lower clamping assembly may be mirror-imaged relative to the rubber cylinder; the lateral guide may be respectively assembled on the upper cone and the lower cone; a first threaded hole may be provided on the upper cava connecting part, and a second threaded hole may be provided on the center tube, the first threaded hole is aligned with the second threaded hole and a shear pin is inserted to lock it; the end of the lower cava may be embedded in the end connected to the drop head; the drop head may be provided with a plurality of return holes arranged obliquely.

[0008] The expansion force F of the double-card single-tube bridge plug is T It can be calculated according to the following formula:

[0009] F T =MAX[F P1 , F P2 ]

[0010]

[0011] In the formula, F P1 is the radial breaking force of the slip connection, F P2 is the tangential fracture force of the slip connection, σ L1 is the tensile strength of the slip material, L K is the slip length, L C is the length of the weakening groove, L T is the length of the embedded part, L Z D is the length of the slip along the conical surface.KW is the maximum outer diameter of the slip, D KN is the maximum inner diameter of the slip, S is the number of slip petals, θ is the angle of each slip petal, γ is the cone angle of the slip body, and R1 is the diameter of the slip petal.

[0012] The present application also relates to an assembly method of a double-card single-barrel bridge plug, comprising the following steps:

[0013] Step 1: With the thick end of the center pipe facing downward, put the upper slip connection part on the center pipe, align the threaded holes on the upper slip connection part with the threaded holes on the center pipe, and lock them with shear pins;

[0014] Step 2: Put the upper slip opening end upward onto the central tube, and connect the upper slip with the upper slip connection part;

[0015] Step 3: Install the lateral guide into the threaded hole on the side of the upper cone to form an assembly, then tapere the assembly downward onto the center tube, and lock the threaded holes corresponding to the upper cone and the center tube by shear pins;

[0016] Step 4, assemble the first protective bowl to the upper cone;

[0017] Step 5, placing the rubber cartridge on the first protective bowl;

[0018] Step 6, placing a second protective bowl on the rubber cylinder to cooperate with the rubber cylinder;

[0019] Step 7, according to step 3, install the lower cone upward onto the central tube;

[0020] Step 8: Install the thick end of the lower slip downward on the center tube, and lock the threaded holes corresponding to the lower cone and the center tube by shear pins;

[0021] Step nine, finally lock the end of the throwing hand and the center pipe together.

[0022] The present application also relates to an operating method of a double-card single-barrel bridge plug, comprising the following steps:

[0023] (1) Apply tension to the throw-out head through the pull rod, and the shear pins at the upper slip connection are sheared off first;

[0024] (2) The upper slip connection part pushes the upper slip, transferring the force to the upper cone, so that the shear pin on the upper cone is sheared off;

[0025] (3) The force transmitted from the upper slip connection is applied to the lower cone through the first retaining bowl, the rubber sleeve, and the second retaining bowl, and the shear pin on the lower cone is sheared off;

[0026] (4) As the pulling force continues to increase, after the upper slip and the lower slip reach the force limit, each slip petal expands and separates along the cone surface, and the lateral guide members fixedly arranged on the upper cone and the lower cone in each slip petal guide the expansion and separation of the cone surface;

[0027] (5) The rubber sleeve is squeezed and expanded by the pressure until the outer surfaces of the upper slip, the lower slip and the rubber sleeve contact the inner wall of the sleeve, and the slip teeth on the slip are embedded in the inner wall of the sleeve to anchor the bridge plug;

[0028] (6) Continue to increase the pulling force, the pull rod shears the release thread on the release head, and the connecting joint and the pull rod are removed together;

[0029] (7) Pumping dissolvable balls to plug the central pipe of the bridge plug and fracturing the upper layer;

[0030] (8) After fracturing is completed, the fluid in the lower layer flows through the single flow channel and normal operations are carried out.

[0031] According to the double-card single-tube bridge plug for preventing setting deviation of the present application, the common problems of loose setting and low backflow efficiency during operation are solved through structural optimization, and the bridge plug has the following technical advantages:

[0032] (1) The design of the lateral guide ensures the uniformity of the slip opening, that is, the stability of the setting is guaranteed, and it has sufficient anchoring force;

[0033] (2) The design of auxiliary return holes saves the time of return work and indirectly saves the economic cost of construction;

[0034] (3) This application proposes an empirical formula for the expansion force of a double-clip single-tube bridge plug, which can be used to guide the structural design of a double-clip single-tube bridge plug, and can also be used to perform strength verification on existing designs, thereby guiding industrial design practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the double-card single-barrel bridge plug of the present application.

[0036] Figure 2 It is a cross-sectional view of the double-card single-barrel bridge plug of the present application.

[0037] Figure 3 It is a cross-sectional view of the upper card seal assembly of the present application.

[0038] Figure 4 It is a schematic diagram of the upper card seal assembly of the present application.

[0039] Figure 5 It is a cross-sectional view of the lower card seal assembly of the present application.

[0040] Figure 6It is a cross-sectional view of the throwing hand of this application. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the present application clearer, the embodiments of the present application will be described in detail in conjunction with the accompanying drawings below. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be arbitrarily combined with each other. The words indicating the orientation in the present application are for the purpose of describing the accompanying drawings and do not constitute any limitation on the scope of protection. As shown in the accompanying drawings, the top of the present application refers to the left side of the drawings, and the bottom refers to the right side of the drawings. For downhole tools, the top refers to the side of the downhole tool close to the wellhead, and the bottom refers to the side of the downhole tool away from the wellhead.

[0042] The purpose of the present application is to provide a bridge plug structural design that can improve the stability of bridge plug setting and the efficiency of downhole return fluid operation. A double-clip single-tube bridge plug that prevents setting deviation according to the present application includes a center pipe 8 and a release head 1, the lower end of the center pipe 8 is connected to the release head 1, and an upper cava connection part 9 is provided on the side of the center pipe 8 away from the release head 1. A pull rod is provided in the center pipe 8, and the pull rod is connected to the release head 1 through a connecting joint. A release thread is provided on the release head 1, so that when the force applied by the pull rod exceeds a threshold, the release thread is sheared, so that the release head 1 moves relative to the center pipe 8.

[0043] Specifically, the central tube 8 and the slip base 9 can be connected by, for example, a threaded fixed connection or by setting a mounting base. Two sets of card sealing components are provided between the central tube 8 and the hand-discharging head 1, and a rubber cylinder 4 is provided between the two sets of card sealing components, and the two sets of card sealing components are mirrored with respect to the rubber cylinder 4. The two sets of card sealing components include an upper card sealing component and a lower card sealing component, the upper card sealing component is arranged between the upper slip connection part 9 and the rubber cylinder 4, and the lower card sealing component is arranged between the rubber cylinder 4 and the hand-discharging head 1. Preferably, the two sides of the rubber cylinder 4 can also be provided with a protective bowl 5, that is, it can include an upper protective bowl and a lower protective bowl. Among them, the upper card sealing component includes an upper slip 7 and an upper cone 6, and the thick end of the upper cone 6 faces downward; the lower card sealing component includes a lower slip 2 and a lower cone 3, and the thick end of the lower cone 3 faces upward. The upper slip 7 and the upper cone 6 can be arranged between the upper slip connection part 9 and the upper protective bowl, and the upper slip 7 is sleeved on the outside of the upper cone 6. The lower cava 2 and the lower cone 3 can be arranged between the lower protective bowl and the throwing hand head 1, and the lower cava 2 is sleeved on the outside of the lower cone 3. The upper cava 7 and the lower cava 2 are respectively provided with a plurality of cava petals, and a separation groove 13 is provided between the plurality of cava petals, and the openings of the separation groove 13 are respectively facing the upper cone 6 and the lower cone 3, so as to facilitate the expansion of the cava. A lateral guide 12 is provided in the separation groove 13, and the lateral guide 12 can be assembled on the upper cone 6 and the lower cone 3. The lateral guide 12 can be, for example, a guide pin, which is used to realize the sliding of the fixed position of the cava to achieve uniform opening, ensure uniform force on the sealing, and provide a better working basis for the later downhole fracturing construction. Preferably, the cava teeth 10 are staggered on each cava petal to make the inlay of the cava teeth more uniform.

[0044] Preferably, a first threaded hole is provided on the outer circumference of the upper cava connection part 9, and a second threaded hole is provided on the center tube 8. During installation, the first threaded hole on the upper cava connection part 9 is aligned with the second threaded hole on the center tube 8, and a shear pin 11 is inserted to lock it. An insert that cooperates with each other may be provided between the upper cava 7 and the upper cava connection part 9, for example, it may be in the form of an insert flange and an insert groove. Similarly, the lower cava and the center tube may also be connected in a similar manner, and an embedded connection method is adopted between the lower cava and the hand-dropping head 1, that is, the end of the lower cava is embeddedly connected to the end of the hand-dropping head 1, and a threaded connection method may be adopted, for example.

[0045] According to the double-clip single-tube bridge plug for preventing the setting deviation of the present application, the assembly process is as follows: Step 1, take the thick end of the center pipe 8 downward, put the upper slip connection part 9 on the center pipe 8 and push it to the upper slip connection part, align the threaded holes on the outer circumference of the upper slip connection part 9 with the threaded holes on the center pipe 8, and lock it with the shear pin 11; Step 2, put the open end of the upper slip 7 on the center pipe 8 upward, and the upper slip 7 and the upper slip connection part 9 are connected by a plug-in fitting; Step 3, lock the lateral guide 12 into the threaded hole on the side of the upper cone 6 Form an assembly, then tapere the assembly downward onto the center pipe 8, take the shear pin 11 to lock the upper cone 6 with the threaded holes corresponding to the center pipe 8; Step 4, assemble the protective bowl 5 to the upper cone 6; Step 5, put in the soluble rubber tube 4; Step 6, place the protective bowl 5 to cooperate with the rubber tube 3; Step 7, install the lower cone 3 upward onto the center pipe 8 according to step 3; Step 8, install the thick end of the lower slip 2 downward onto the center pipe, paying attention to cooperate with the lateral guide 12; Step 9, finally, lock the throw-out head 1 through the thread at the end of the center pipe 8. The design of the bridge plug fully considers the requirements of well operations. After the sealing is completed, the anchoring force is strong and the operation is stable. At the same time, the design takes into account the increase of the return efficiency, providing a basis for the rapid return in the later stage and improving the construction speed.

[0046] According to the present application, a double-clip single-tube bridge plug for preventing setting deviation has the following operation process: during the setting process of the bridge plug, the fixed surface is the left end surface of the upper cava connection part 9, and a pulling force is applied to the release head 1 through the pull rod. Since the upper cava connection part 9, the upper cone 6, and the lower cone 3 are all provided with a locking shear pin 11, when the pull rod applies a pulling force to the release head 1, as the pulling force increases, the shear pin of the upper cava connection part 9 is sheared first, and then the upper cava connection part 9 pushes the upper cava 7 to transfer the force to the upper cone 6, so that the shear pin 11 on the upper cone 6 is also sheared, and then the force transmitted from the upper cava connection part 9 is applied to the lower cone 3 through the first protective bowl, the rubber cylinder 4, and the second protective bowl, and the shear pin 11 on the lower cone 3 is also sheared. The purpose of the shear pins of the above three components is to prevent the bridge plug from being subjected to external forces in a non-working state, causing the various components of the bridge plug to work prematurely and cause the bridge plug to fail. As the pulling force increases, the upper slip 7 and the lower slip 2 reach the force limit, and the slip petals expand and separate along the cone surface. At the same time, the rubber tube 4 is gradually squeezed and expanded by the pressure until the outer surfaces of the upper slip 7, the lower slip 2, and the rubber tube 4 contact the inner wall of the sleeve. As the pulling force increases, the slip teeth 10 on the slips are embedded in the casing wall, playing the role of anchoring the bridge plug.

[0047] When the thrust reaches a certain level, the setting rod shears the release thread on the release head 1, and the setting connection joint and the setting rod are taken out together with the setting tool. Then, a soluble ball of corresponding size is pumped to plug the central pipe 8 of the bridge plug, and the upper layer is fracturing. After fracturing, the fluid in the lower layer can flow through the single flow channel, so as to carry out normal blowout or production. During the blowout and production process, the soluble bridge plug gradually dissolves in the wellbore fluid and finally disappears.

[0048] like Figure 2-3 As shown, the lateral guide 12 of the present application is located on the cone in a three-dimensional assembly relationship, between the separation grooves of the slip flaps. The principle that the lateral guide 12 can prevent the setting seal from being offset is the guiding function, that is, it can allow each slip flap to move in the direction of the preset bridge plug axis. When the slip flaps of the slip flaps are unevenly stressed and deflected and cannot expand, the lateral guide 12 can forcibly prevent the offset phenomenon from occurring. Figure 2 For example, the slip flaps of the upper slip 7 are pushed to the right by the upper slip connection part 9 and expand respectively. During the movement, the connection points of each slip flap will gradually crack due to limited strength, and a load will be added inward or outward, causing the slip flap to deflect inward or outward. At this time, since the lateral guide 12 is located on the side of the slip flap, the circumferential position will not change due to the axial movement of the slip. When the slip flap moves to a certain position, it will touch the lateral guide 12, causing it to stop deflecting and only move in the axial direction, thereby ensuring the stability of the moving direction of the slip flap and ensuring that the slip expands evenly.

[0049] When designing the bridge plug of this application, the expansion force of the slip is an important design parameter, which can be used to determine the size of the external load that prevents the bridge plug from being set prematurely, and is convenient for protecting the bridge plug during use; it can be used to calculate the release force required for the slip to be fully opened, because the release force is guaranteed by the threads of the base, but how much release force needs to be designed to meet the requirements, and the expansion force requirements need to be met; it is also an important reference parameter for the design of the cone surface angle of the cone seat, because the release force is converted into expansion force through the cone surface pressure of the cone seat. For the double slip form of this application, the expansion force F of the bridge plug of this application is T It can be calculated according to the following empirical formula:

[0050] F T =MAX[F P1 , F P2 ]

[0051]

[0052] In the formula, F P1 is the radial breaking force of the slip connection, F P2 is the tangential fracture force of the slip connection, σ L1 is the tensile strength of the slip material, L K is the slip length, LC is the length of the dividing slot, L T L is the length of the installation groove of the lower slip embedded in the thrower head. Z D is the length of the slip along the conical surface. KW is the maximum outer diameter of the slip, D KN is the maximum inner diameter of the slip, S is the number of slip petals, θ is the angle of each slip petal, γ is the taper angle of the slip body, and R1 is the diameter of the slip petal. The taper angle described in this application is reflected in the cross-sectional view as the angle between the side extension line of the slip and the longitudinal center axis of the bridge plug.

[0053] Conversely, the expansion force design value F of the bridge plug is known T and the tensile strength of the slip material σ L1 , the designed slip size can be verified to meet the design requirements. The following table is the example data for guiding bridge plug design.

[0054] Table 1 Example of bridge plug design

[0055] parameter unit Example 1 Example 2 Example 3 Example 4 <![CDATA[F T ]]> N 9322 10332 14502 10154 γ Rad 0.244346 0.244346 0.244346 0.244346 <![CDATA[L Z ]]> mm 77 77 77 77 <![CDATA[L C ]]> mm 60 60 55 60 <![CDATA[L T ]]> mm 8 8 8 8 <![CDATA[σ L1 ]]> Mpa 330 330 330 330 <![CDATA[D KW ]]> mm 101.2 101.2 101.2 104 <![CDATA[D KN ]]> mm 92 88.6 92 92 S piece 6 6 6 6 θ Rad π / 3 π / 3 π / 3 π / 3 <![CDATA[R1]]> mm 44.4 44.4 44.4 44.4 <![CDATA[L Z ]]> mm 44.5 44.5 44.5 44.5

[0056] Figure 6 The cross-sectional view of the throw-away head 1 of the present application is provided with a plurality of return holes 14 arranged obliquely. The bridge plug of the present application improves the return efficiency by adding auxiliary return holes on the side wall of the throw-away head. For example, for a base with a commonly used outer diameter of 110 mm, 10 φ10 circular through holes can be distributed in the circumferential direction of the side wall of the throw-away head, and the angle between the axis of the circular hole and the axis of the bridge plug is 45-55°, preferably 50°, which can achieve the best return effect.

[0057] Compared with the traditional bridge plug, this application has obvious structural differences, mainly in the dropper, lower slip and upper slip. The difference is:

[0058] (1) The bridge plug of the present application adds lateral guides between the slip petals of the slip to ensure that the unexpanded slip petals expand smoothly and evenly during the movement of the slip, thereby ensuring the stability and safety of the setting.

[0059] (2) In addition to the above-mentioned functions and effects, the optimized structure of the bridge plug of the present application also adds a return hole structure design to improve the efficiency of the return fluid, which greatly improves the return efficiency and solves the high construction cost problem caused by the low return efficiency of the bridge plug.

[0060] Although the implementation methods disclosed in this application are as above, the contents described are only implementation methods adopted for facilitating the understanding of this application, and are not intended to limit this application. Any technician in the technical field to which this application belongs can make any modifications and changes in the form and details of implementation without departing from the spirit and scope disclosed in this application, but the scope of patent protection of this application shall still be based on the scope defined in the attached claims.

Claims

1. A double-card single-barrel bridge plug for preventing setting deviation, characterized in that: The utility model discloses a method for disassembling and disassembling a plurality of sliding plates, wherein the plurality of sliding plates are connected to each other with a plurality of sliding plates, and the plurality of sliding plates are connected with each other with a plurality of sliding plates.

2. The double-card single-barrel bridge plug according to claim 1 is characterized in that: An upper protective bowl and a lower protective bowl are respectively provided on both sides of the rubber cylinder, the upper slip and the upper cone are arranged between the upper slip connection part and the upper protective bowl, and the lower slip and the lower cone are arranged between the lower protective bowl and the throwing head.

3. The double-card single-tube bridge plug according to claim 1 is characterized in that: The upper sealing assembly and the lower sealing assembly are arranged in a mirror image relative to the rubber cylinder.

4. The double-card single-tube bridge plug according to any one of claims 1 to 3, characterized in that: The lateral guides are respectively mounted on the upper cone and the lower cone.

5. The double-card single-tube bridge plug according to claim 2, characterized in that: The upper slip connection portion is provided with a first threaded hole, and the central pipe is provided with a second threaded hole. The first threaded hole is aligned with the second threaded hole and a shear pin is inserted to lock them.

6. The double-card single-tube bridge plug according to claim 5, characterized in that: The end of the lower slip is embedded and connected to the end of the throwing head.

7. The double-card single-tube bridge plug according to any one of claims 1-3 and 5-6, characterized in that: The dropper head is provided with a plurality of return holes which are arranged obliquely.

8. The double-card single-tube bridge plug according to any one of claims 1-3 and 5-6, characterized in that: The expansion force F of the double-card single-tube bridge plug T Calculate according to the following formula: F T =MAX[F P1 ,F P2 ] In the formula, F P1 is the radial breaking force of the slip connection, F P2 is the tangential fracture force of the slip connection, σ L1 is the tensile strength of the slip material, L K is the slip length, L C is the length of the weakening groove, L T is the length of the embedded part, L Z D is the length of the slip along the conical surface. KW is the maximum outer diameter of the slip, D KN is the maximum inner diameter of the slip, S is the number of slip petals, θ is the angle of each slip petal, γ is the cone angle of the slip body, and R1 is the diameter of the slip petal.

9. A method for assembling a double-card single-tube bridge plug, characterized in that: The following steps are involved: Step 1: With the thick end of the center pipe facing downward, put the upper slip connection part on the center pipe, align the threaded holes on the upper slip connection part with the threaded holes on the center pipe, and lock them with shear pins; Step 2: Put the upper slip opening end upward onto the central tube, and connect the upper slip with the upper slip connection part; Step 3: Install the lateral guide into the threaded hole on the side of the upper cone to form an assembly, then tapere the assembly downward onto the center tube, and lock the threaded holes corresponding to the upper cone and the center tube by shear pins; Step 4, assemble the first protective bowl to the upper cone; Step 5, placing the rubber cartridge on the first protective bowl; Step 6, placing a second protective bowl on the rubber cylinder to cooperate with the rubber cylinder; Step 7, according to step 3, install the lower cone upward onto the central tube; Step 8: Install the thick end of the lower slip downward on the center tube, and lock the threaded holes corresponding to the lower cone and the center tube by shear pins; Step nine, finally lock the end of the throwing hand and the center pipe together.

10. A method for operating a double-card single-tube bridge plug, characterized in that: The following steps are involved: (1) Apply tension to the throw-out head through the pull rod, and the shear pins at the upper slip connection are sheared off first; (2) The upper slip connection part pushes the upper slip, transferring the force to the upper cone, so that the shear pin on the upper cone is sheared off; (3) The force transmitted from the upper slip connection is applied to the lower cone through the first retaining bowl, the rubber sleeve, and the second retaining bowl, and the shear pin on the lower cone is sheared off; (4) As the pulling force continues to increase, after the upper slip and the lower slip reach the force limit, each slip petal expands and separates along the cone surface, and the lateral guide members fixedly arranged on the upper cone and the lower cone in each slip petal guide the expansion and separation of the cone surface; (5) The rubber sleeve is squeezed and expanded by the pressure until the outer surfaces of the upper slip, the lower slip and the rubber sleeve contact the inner wall of the sleeve, and the slip teeth on the slip are embedded in the inner wall of the sleeve to anchor the bridge plug; (6) Continue to increase the pulling force, the pull rod shears the release thread on the release head, and the connecting joint and the pull rod are removed together; (7) Pumping dissolvable balls to plug the central pipe of the bridge plug and fracturing the upper layer; (8) After fracturing is completed, the fluid in the lower layer flows through the single flow channel and normal operations are carried out.

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