Slip type underground plugging tool capable of preventing setting deviation

Abstract

The invention relates to a slip type underground plugging tool capable of preventing setting deviation, which comprises a base, a central pipe and a conical seat, a slip is arranged between the base and the conical seat, the slip is arranged outside the central pipe, the first end of the central pipe is connected with the base, the second end of the central pipe is connected with the conical seat, and the second end of the central pipe is connected with the conical seat. Weakening grooves facilitating opening of the slip are formed in the circumference of the slip at intervals, the weakening grooves are alternately formed in two opening directions facing the conical seat and the base respectively, and lateral fasteners are arranged in the weakening grooves with the openings facing the base. It can be ensured that the slips are stressed to move in the specific direction, and the percent of pass of in-well setting of an underground plugging tool is greatly increased.

Description

Technical Field

[0001] The present application relates to a downhole plugging tool, and in particular to a slip-type downhole plugging tool capable of preventing the seal from being dislocated. Background Art

[0002] Downhole plugging tools are widely used in oilfield exploration and development to plug the lower well section during the construction of stratified fracturing, stratified acidizing, and stratified oil testing of oil and water wells. Common downhole plugging tools include bridge plugs and packers. When going down the well, it can be transported to the predetermined position of the wellbore by cable or tubing. The pressure generated by the gunpowder blasting, hydraulic setting or mechanical setting tool acts on the slips, and the tension acts on the tension rod. The upper and lower cones apply two forces, upward pressure and downward pull, to the sealing rubber tube. When the tension reaches a certain value, the tension rod breaks, and the setting tool is separated from the downhole plugging tool. At this time, the locking device on the center tube of the downhole plugging tool takes effect, the slips are broken and embedded in the inner wall of the casing, the rubber tube expands and seals, and the setting is completed.

[0003] At present, most of the downhole plugging tools used in major oil and gas fields have uneven opening of the slips during the construction process, which leads to leakage during pressure testing. The slips need to be taken out from the well or dissolved before the construction can continue, wasting a lot of time and economic costs. The main reason for the uneven opening of the slips during the sealing process is that the existing technology mostly uses a petal-type sealing joint, and the gaps between the petals are all opened in the same direction. When the slips move toward the cone seat, the petals are often subjected to uneven force, which causes the original movement trajectory of the petals to change, resulting in the offset of the sealing.

[0004] For example, the Chinese patent application with application number 202210072257.2 discloses a bridge plug seating mechanism, in which the disclosed petal-claw type fixed sleeve includes a second locking block, a fixed sleeve ring and a fixed sleeve petal claw, the upper end of the fixed sleeve petal claw is connected to the fixed sleeve ring, and the lower end of the fixed sleeve petal claw is connected to the second locking block. The fixed sleeve petal claw is in the form of opening to one side. The problem brought about by this structural form is that the force is easily uneven during movement, and the movement trajectory of each petal is offset, thereby causing the seating to be offset. After the seating is offset, the cava is not opened enough and fails to be embedded and stuck in the inner wall of the casing, causing the bridge plug to fall directly from the casing and the seating fails. Summary of the invention

[0005] The purpose of the present invention is to design a slip-type downhole plugging tool that can prevent the slip from being set in an offset manner. By arranging lateral fasteners in a weakened groove opening toward the base, the slip can move along a specific path during the expansion process, thereby solving the problem that the slip cannot be set evenly.

[0006] The present application relates to a slip-type downhole plugging tool capable of preventing the setting seal from being displaced, comprising a base, a center tube and a conical seat, a slip being arranged between the base and the conical seat, the slip being arranged outside the center tube, the first end of the center tube being connected to the base, the second end of the center tube being connected to the conical seat, weakened grooves for facilitating the opening of the slips being arranged at intervals on the circumference of the slips, the weakened grooves being alternately provided with two opening directions facing the conical seat and the base respectively, and a lateral fastener being arranged in the weakened groove with the opening facing the base.

[0007] Wherein, the first end of the center tube is connected to the base through a thread, the second end of the center tube is connected to the conical seat through a locking ring, and the locking ring is installed on the conical seat; the second end of the center tube is connected to the locking ring through a one-way thread; the lateral fastener comprises a threaded portion and a bare rod portion, the threaded portion is screwed into the conical seat and abuts against the conical seat; a first expansion ring and a second expansion ring are provided on the outer side of the end of the conical seat close to the base, the first expansion ring and the second expansion ring are used to tighten the cava, an upper pre-tightening ring and a lower pre-tightening ring are provided on the outer side of the cava, and the downhole plugging tool is an all-metal downhole plugging tool.

[0008] Among them, the assembly process of the downhole plugging tool is: first, install the locking ring on the conical seat, then install the center pipe on the locking ring, and then install the first expansion ring and the second expansion ring on the conical seat; secondly, install the lower preload ring and the upper preload ring on the slip, and then install the installed slip on the conical seat; thirdly, install the base on the center pipe, and finally install the lateral fastener on the conical seat.

[0009] The expansion force F of the downhole plugging tool is T It can be calculated according to the following empirical formula:

[0010] F T =MAX[F H1 ,F H2 , F P1 ,F P2 ]

[0011] F H1 =σ L1 B 1 δ 1 =σ L1 (D SHW -D SHN )B 1

[0012] F H2 =σ L2 B 2 δ 2 =σL2 (D XHW -D XHN )B 2

[0013] F P1 =1 / 2σ L3 [(L K -L C )(D XHW -D XHN )+(D XHN -D KN )B 2 ]

[0014]

[0015] In the formula, F H1 is the destructive force of the upper preload ring, F H2 is the destructive force of the lower preload ring, 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 upper preload ring, σ L2 is the tensile strength of the lower preload ring, B 1 B is the effective width of the upper preload ring, 2 is the effective width of the lower preload ring, δ 1 is the effective thickness of the upper preload ring, δ 2 is the effective thickness of the lower preload ring, D SHW D is the maximum outer diameter of the upper preload ring. SHN D is the maximum inner diameter of the upper preload ring. XHW is the maximum outer diameter of the lower preload ring, D XHN is the maximum inner diameter of the lower preload ring, σ L3 is the tensile strength of the slip, L K is the slip length, L C is the length of the weakening groove, D KN is the maximum inner diameter of the slip, D KW is the maximum outer diameter of the slip, S is the number of slip petals, and θ is the angle of each slip petal.

[0016] The downhole plugging tool of the present application optimizes the structure of the cava and the adapter components based on the movement process of the cava, ensuring that the cava is displaced in a specific direction under force, better solving the problem that the cava cannot be evenly sealed, and greatly improving the qualified rate of the downhole plugging tool in the well, thereby saving time and construction costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a cross-sectional view of the slip-type downhole plugging tool of the present application which can prevent the setting seal from being offset.

[0018] Figure 2 It is a schematic diagram of the connection relationship between the slips and the cone seat of the downhole plugging tool of the present application.

[0019] Figure 3 It is a schematic diagram of an implementation of a lateral fastener of a downhole plugging tool of the present application.

[0020] Figure 4 It is a structural schematic diagram of the slips of the downhole plugging tool of the present application.

[0021] Figure 5 It is a structural schematic diagram of the one-way thread of the present application.

[0022] Figure 6 It is a schematic diagram of a single-card single-tube bridge plug adopting the structure of the present application. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme 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 combined with each other arbitrarily. In the description of the present application, reference to the term "embodiment" or "example" and similar descriptions means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not need to be directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, in the absence of mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples.

[0024] It should be noted that all directional indications of the present invention, such as up, down, left, right, front, back, etc., are only used to explain the relative position relationship, movement, etc. between the components in a certain specific posture as shown in the accompanying drawings. If the specific posture changes, the directional indication will also change accordingly. In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0025] According to the present application, a cava-type downhole plugging tool that can prevent the setting of the seal from being offset includes a base 1, a center pipe 3 and a cone seat 10. A cava 4 is provided between the base 1 and the cone seat 10. The cava 4 is arranged on the outside of the center pipe 3. The first end of the center pipe 3 is connected to the base 1 through a thread, and the second end of the center pipe 3 is connected to the cone seat 10 through a locking ring 9. The locking ring 9 is installed on the cone seat 10. In particular, the second end of the center pipe 3 is connected to the locking ring 9 through a 90° one-way thread, which can achieve unidirectional sliding without destroying the thread locking structure. A first expansion ring 7 and a second expansion ring 8 are provided on the outer side of the end of the cone seat 10 close to the base 1. The first expansion ring 7 and the second expansion ring 8 are used to hold the cava 4 tightly. An upper pre-tightening ring 6 and a lower pre-tightening ring 2 are provided on the outer side of the cava 4 for pre-tightening to prevent premature setting. The side of the slip 4 is provided with a lateral fastener 12, such as a guide pin, which is used to slide the fixed position of the slip to achieve uniform opening, ensure uniform force on the setting seal, and provide a better working foundation for later downhole fracturing construction. The slip-type downhole plugging tool of the present application is preferably a full-metal soluble downhole plugging tool.

[0026] The advantage of the one-way thread is that it has one-way anti-slip properties. In this application, under the premise of ensuring the material strength of the central tube 4 and the base 1, the thread structure used can also achieve the anti-slip effect. Figure 5 As shown, the thread is arranged in a right-angled trapezoidal shape, and the angle between the bevel of the thread and the longitudinal direction of the thread is 30 degrees. In order to ensure the tightness of the threaded connection between the center tube 4 and the base 1, the thread shapes on the two match each other. The present application adopts such a 90° one-way thread, and the right-angled sides of the two threaded parts are interlocked with each other, so as to form a joint surface perpendicular to the longitudinal direction, thereby maximizing the joint surface and ensuring the connection strength and tightness of the thread.

[0027] According to the present application, the assembly connection relationship of a slip-type downhole plugging tool for preventing the setting seal from being displaced is as follows: first, the locking ring 9 is installed on the conical seat 10, and then the center pipe 3 is installed on the locking ring 9, and then the first expansion ring 7 and the second expansion ring 8 are installed on the conical seat 10; secondly, the lower preload ring 2 and the upper preload ring 6 are installed on the slip 4, and then the installed slip 4 is installed on the conical seat 10; thirdly, the base 1 is installed on the center pipe 3, and finally the lateral fastener 12 for preventing the setting seal from being displaced is installed on the conical seat 10, and during the advancement process of the slip, it moves according to the designed sliding trajectory to prevent the pressure failure caused by uneven cracking during the opening process of the slip.

[0028] In order to prevent the setting seal from being offset, the present application not only modifies the shape of each petal of the slip in the prior art, but also adds a calibration component when the force on each petal of the slip is uneven, so that the movement trajectory of each petal of the slip does not deviate. Figure 2As shown, weakened grooves 11 are provided at intervals on the circumference of the slip 4 to facilitate the opening of the slip. The weakened grooves 11 are alternately provided with two opening directions, one of which is upward, that is, the opening is toward the direction of the cone seat 10, and the other is downward, that is, the opening is toward the direction of the base 1. In the present application, the lateral fasteners 12 are only provided in the weakened grooves 11 with the openings facing downward, that is, the lateral fasteners 12 are provided at intervals in the weakened grooves 11, which can prevent the risk of the slip not being fully opened and the setting condition being poor. The reason is that when the slip 4 moves toward the cone seat 10, the space of the weakened groove 11 with the openings facing upward will gradually decrease. When the slip 4 moves a certain distance, the space of the weakened groove facing upward may be insufficient, thereby blocking the lateral fasteners 12; however, the weakened groove with the opening facing downward is completely opposite. When the slip 4 moves toward the cone seat 10, the space of the weakened groove 11 with the openings facing downward will gradually increase, and will not block the lateral fasteners 12.

[0029] like Figure 3 As shown, the lateral fastener 12 includes a threaded portion and a smooth rod portion. The threaded portion is screwed into the cone seat 10 and abuts against the cone seat 10 to ensure a stable connection; the smooth rod portion leaks out and contacts the slip 4, which can effectively reduce the resistance during the movement of the slip 4. At the same time, the smooth rod has a higher strength than the thread, which can ensure that the slip petals have sufficient support when they are offset. Multiple lateral fasteners 12 are arranged in the weakened groove 11 facing downward along the circumferential direction. When the slip 4 is offset during movement, multiple lateral fasteners 12 will prevent the offset, thereby ensuring that the movement trajectory is not offset and the sealing is not biased; it can also make the slip petals open evenly, the spacing between the petals is equal, and when the slip is fully opened, it will be tightly stuck on the inner wall of the casing, achieving a good sealing effect.

[0030] The present application sets the intervals of the weakened grooves on the circumferential side of the cava to open upward and open downward, and sets lateral fasteners in the weakened grooves opening downward, so that when the cava moves toward the conical seat, the space of the weakened grooves opening downward will gradually increase and will not block the lateral fasteners. At the same time, the lateral fasteners can also prevent the displacement of the petals of the cava, thereby ensuring that the moving trajectory is not offset and the sealing is not offset. The downhole plugging tool of the present application has a novel structural design, which can solve the problem of the early opening of the cava before the downhole plugging tool is sealed. In addition, when the cava needs to be opened, the problem of controllable opening sequence of the upper and lower cava can be solved by designing the size difference of the upper and lower preload rings. The reserved locking point of the conical seat 10 cooperates with the weakened groove 11 and the lateral fastener 12 on the cava 4 to ensure that the cava is opened evenly, avoiding the secondary descent due to uneven opening of the cava, improving the qualification rate of descent and reducing construction costs.

[0031] When designing the downhole plugging tool of the present application, the expansion force of the cava is an important design parameter, which can be used to determine the size of the external load that prevents the downhole plugging tool from prematurely setting, and is convenient for protecting the downhole plugging tool during use; it can be used to calculate the release force required to fully open the cava. This is because the release force is guaranteed by the threads of the base, but the 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 seat cone angle, because the release force is converted into expansion force through the cone seat cone pressure. The expansion force F of the downhole plugging tool of the present application T It can be calculated according to the following empirical formula:

[0032] F T =MAX[F H1 ,F H2 , F P1 ,F P2 ]

[0033] F H1 =σ L1 B 1 δ 1 =σ L1 (D SHW -D SHN )B 1

[0034] F H2 =σ L2 B 2 δ 2 =σ L2 (D XHW -D XHN )B 2

[0035] F P1 =1 / 2σ L3 [(L K -L C )(D XHW -D XHN )+(D XHN -D KN )B 2 ]

[0036]

[0037] In the formula, F H1 is the destructive force of the upper preload ring, F H2 is the destructive force of the lower preload ring, 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 upper preload ring, B 1 B is the effective width of the upper preload ring,2 is the effective width of the lower preload ring, δ 1 D is the effective thickness of the upper preload ring. SHW D is the maximum outer diameter of the upper preload ring. SHN is the maximum inner diameter of the upper preload ring, σ L2 is the tensile strength of the lower preload ring, D XHW is the maximum outer diameter of the lower preload ring, D XHN is the maximum inner diameter of the lower preload ring, δ 2 is the effective thickness of the lower preload ring, σ L3 is the tensile strength of the slip, L K is the slip length, L C is the length of the weakening groove, 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, D KW is the maximum outer diameter of the slip.

[0038] Conversely, the expansion force design value F of the downhole plugging tool is known T The performance parameters of the slip material can be used to verify the designed slip size to meet the design requirements. The following table shows the calculation parameters of the design guided by the above formula.

[0039] Table 1 Design parameter example of downhole plugging tool

[0040] parameter unit Example 1 Example 2 Example 3 Example 4 <![CDATA[F T ]]> N 46305 42525 48255 123217 <![CDATA[σ L1 ]]> MPa 300 300 300 300 <![CDATA[D SHW ]]> mm 104 104 104 104 <![CDATA[D SHW ]]> mm 101 101 101 101 <![CDATA[B 1 ]]> mm 6.5 6.5 6.5 6.5 <![CDATA[σ L2 ]]> MPa 300 300 300 300 <![CDATA[D XHW ]]> mm 107 107 107 107 <![CDATA[D XHW ]]> mm 101 101 101 101 <![CDATA[B 2 ]]> mm 6.5 6.5 6.5 6.5 <![CDATA[σ L3 ]]> MPa 300 300 300 300 <![CDATA[L K ]]> mm 90 90 90 90 <![CDATA[L C ]]> mm 80.8 85 80.8 80.8 <![CDATA[B 2 ]]> mm 6.5 6.5 6.5 6.5 <![CDATA[D KN ]]> mm 62 62 60 62 S piece 8 8 8 7 θ rad 0.78539815 0.78539815 0.78539815 0.78539815 <![CDATA[D KW ]]> mm 107 107 107 107

[0041] 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 slip-type downhole plugging tool capable of preventing the setting seal from being offset, characterized in that: It includes a base, a center tube and a conical seat, a slip is provided between the base and the conical seat, the slip is arranged on the outside of the center tube, the first end of the center tube is connected to the base, and the second end of the center tube is connected to the conical seat, weakened grooves for facilitating the opening of the slip are provided at intervals on the circumference of the slip, the weakened grooves are alternately provided with two opening directions facing the conical seat and the base respectively, and a lateral fastener is provided in the weakened groove with the opening facing the base.

2. The slip-type downhole plugging tool according to claim 1, characterized in that: The first end of the central tube is connected to the base through a thread, and the second end of the central tube is connected to the cone seat through a locking ring, and the locking ring is installed on the cone seat.

3. The slip-type downhole plugging tool according to claim 2, characterized in that: The second end of the central tube is connected to the locking ring via a one-way thread.

4. The slip-type downhole plugging tool according to any one of claims 1 to 3, characterized in that: The lateral fastener comprises a threaded portion and a polished rod portion, wherein the threaded portion is screwed into the conical seat and abuts against the conical seat.

5. The slip-type downhole plugging tool according to claim 2, characterized in that: A first expansion ring and a second expansion ring are provided on the outer side of the end of the cone seat close to the base, and the first expansion ring and the second expansion ring are used to tighten the cava.

6. The slip-type downhole plugging tool according to claim 5, characterized in that: An upper pre-tightening ring and a lower pre-tightening ring are arranged on the outer side of the slip.

7. The slip-type downhole plugging tool according to any one of claims 1 to 3 and 6, characterized in that: The downhole plugging tool is an all-metal downhole plugging tool.

8. The slip-type downhole plugging tool according to claim 6, characterized in that: The assembly process of the downhole plugging tool is as follows: first, install the locking ring on the conical seat, then install the center pipe on the locking ring, and then install the first expansion ring and the second expansion ring on the conical seat; secondly, install the lower preload ring and the upper preload ring on the slip, and then install the installed slip on the conical seat; thirdly, install the base on the center pipe, and finally install the lateral fastener on the conical seat.

9. The slip-type downhole plugging tool according to any one of claims 1-3, 6 and 8, characterized in that: The expansion force F of the downhole plugging tool T It can be calculated according to the following empirical formula: F T =MAX[F H1 ,F H2 ,F P1 ,F P2 ] F H1 =σ L1 B1δ1=σ L1 (D SHW -D SHN )B1 F H2 =σ L2 B2δ2=σ L2 (D XHW -D XHN )B2 F P1 =1 / 2σ L3 [(L K -L C )(D XHW -D XHN )+(D XHN -D KN )B2] In the formula, F H1 is the destructive force of the upper preload ring, F H2 is the destructive force of the lower preload ring, 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 upper preload ring, σ L2 is the tensile strength of the lower preload ring, B1 is the effective width of the upper preload ring, B2 is the effective width of the lower preload ring, δ1 is the effective thickness of the upper preload ring, δ2 is the effective thickness of the lower preload ring, D SHW D is the maximum outer diameter of the upper preload ring. SHN D is the maximum inner diameter of the upper preload ring. XHW is the maximum outer diameter of the lower preload ring, D XHN is the maximum inner diameter of the lower preload ring, σ L3 is the tensile strength of the slip, L K is the slip length, L C is the length of the weakening groove, D KN is the maximum inner diameter of the slip, D KW is the maximum outer diameter of the slip, S is the number of slip petals, and θ is the angle of each slip petal.

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