Expansion device for expansion pipe

Abstract

The invention relates to the technical field of underground expansion pipe expansion tools, and particularly discloses an expansion device for an expansion pipe, which comprises an expansion cone assembly, an expansion pipe bottom plug and a sealing pipe, the expansion pipe bottom plug is used for being connected with the sealing pipe, and the expansion cone assembly is used for being connected in the front part of an end flaring of the expansion pipe. The expansion pipe bottom plug is used for being slidably connected into the rear portion of a flaring at the end of the expansion pipe, a limiting structure for preventing the expansion pipe bottom plug from sliding in the direction away from the expansion cone assembly is arranged between the expansion pipe bottom plug and the expansion pipe, an oil inlet pipe is connected to the expansion cone assembly in a sealed mode and used for inputting pressure oil into the sealing pipe, and a pull rod assembly is connected to the oil inlet pipe. The pull rod assembly penetrates through an axial hole formed in the expansion pipe bottom plug and then extends into the sealing pipe. According to the device, the expansion pipe bottom plug can be safely treated after expansion construction is finished, the safe fishing capacity of the expansion pipe bottom plug is improved, and safety accidents can be prevented if the expansion pipe bottom plug is clamped in a well.

Description

Technical Field

[0001] The invention relates to the technical field of downhole expansion tube expansion tools, in particular to an expansion device for an expansion tube. Background Art

[0002] When the expansion pipe is constructed underground, it is necessary to use the expansion cone assembly, the expansion pipe bottom plug and the sealing pipe to form a sealed cavity, and the expansion tool assembly is pushed to move by injecting high-pressure liquid into the sealed cavity to complete the expansion operation of the expansion pipe. However, as an independent component, the expansion pipe bottom plug needs to be salvaged once after the expansion pipe construction is completed. This increases the operating cost. The common expansion tool assembly and bottom plug self-salvage system, especially in the 108*7mm expansion pipe system, has low reliability due to size limitations. In extreme cases, there are debris on the well wall that affects the inner diameter, and the pulling force of salvaging the expansion pipe bottom plug through the resistance point is high. When the salvage resistance exceeds the tensile strength of the tie rod assembly, it will also cause the tie rod assembly to break, resulting in underground accidents. In order to avoid underground accidents, it is necessary to design a safe and reasonable release plan, rather than passively increasing the pulling force, relying on the expansion cone assembly to drive the tie rod assembly to salvage the expansion pipe bottom plug and continue to move upward until the tie rod assembly breaks. Summary of the invention

[0003] The purpose of the present invention is to provide an expansion device for an expansion pipe, which can safely handle the bottom blockage of the expansion pipe after the expansion construction is completed, increase the safe salvage capacity of the bottom blockage of the expansion pipe, and prevent the occurrence of safety accidents if the bottom blockage of the expansion pipe is stuck in the well.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] An expansion device for an expansion pipe, comprising an expansion cone assembly, an expansion pipe bottom plug and a sealing pipe, wherein the expansion pipe bottom plug is used to be connected to the sealing pipe, the expansion cone assembly is used to be connected in the front part of the expansion pipe end flare, the expansion pipe bottom plug is used to be slidably connected in the rear part of the expansion pipe end flare, and a limiting structure is provided between the expansion pipe bottom plug and the expansion pipe to prevent the expansion pipe bottom plug from sliding away from the expansion cone assembly, an oil inlet pipe is sealedly connected to the expansion cone assembly, and the oil inlet pipe is used to input pressure oil into the sealing pipe, A tie rod assembly is connected to the oil inlet pipe, and the tie rod assembly passes through the axial hole opened on the bottom plug of the expansion tube and then extends into the sealing tube. A limit block is provided at one end of the tie rod assembly extending into the sealing tube, and the width of the limit block is larger than the aperture of the axial hole opened on the bottom plug of the expansion tube. The tie rod assembly is used to pull the limit block to slide along the sealing tube, and the limit block and the tie rod assembly are connected by a shearable structure. The shear strength of the shearable structure is less than a safety threshold, and the safety threshold is determined according to the tensile strength of the expansion tube.

[0006] In a further solution, the pull rod assembly includes a connecting oil pipe, multiple pull rods, a first connecting pipe clamp and a second connecting pipe clamp. The multiple pull rods are connected to each other to form a long rod through the first connecting pipe clamp. One end of the connecting oil pipe is connected to the oil inlet pipe, and the other end is connected to one end of the long rod through the second connecting pipe clamp. The other end of the long rod is connected to the limit block through the shearable structure.

[0007] In a further solution, the shearable structure includes a shear pin and a pin hole, the pin hole matches the shear pin, and the pin hole is arranged on a limit block and a pull rod connected to the limit block.

[0008] In a further solution, the diameter of the connecting oil pipe is larger than the diameter of the pull rod, and the pull rod is a solid tube.

[0009] In a further solution, the length of the sealing tube is greater than the expansion length of the expansion tube.

[0010] In a further solution, both ends of the connecting oil pipe are connected to the second connecting pipe clamp and the oil inlet pipe respectively through threads.

[0011] In a further solution, a liquid outlet is provided on the connecting oil pipe, a sealing groove is provided on the expansion cone assembly, a sealing ring is connected to the sealing groove, and the sealing ring is used for sealing between the expansion cone assembly and the expansion pipe.

[0012] In a further solution, the limiting structure is connected to the expansion pipe end flare via a sealing member at one end away from the expansion cone assembly.

[0013] In a further solution, the limiting structure includes a wedge-shaped claw and a wedge-shaped groove, and the wedge-shaped groove and the wedge-shaped claw are respectively arranged on the expansion tube end flare and the expansion tube bottom plug, and the wedge-shaped claw can slide along the wedge-shaped groove toward one end of the expansion cone assembly, and limit sliding in the opposite direction of the direction.

[0014] In a further solution, the limiting structure includes a limiting protrusion, which is arranged on the expansion end of the expansion tube and is used to limit the expansion tube bottom plug from sliding in a direction away from the expansion cone assembly.

[0015] Beneficial effects of the present invention:

[0016] The present invention connects the bottom plug of the expansion pipe and the expansion cone assembly through the tie rod assembly, so that after the expansion is completed, the expansion cone assembly can be driven to be salvaged, thereby completing the integrated expansion and salvage work when the expansion pipe is installed underground. When the pulling force is large and there is a risk of an accident, the shearable structure can be used to ensure that the tie rod assembly automatically releases the bottom plug when the force is close to its tensile limit, thereby avoiding the complication of accidents and ensuring the safety of salvage.

[0017] A combined tie rod assembly is adopted, with a connecting oil pipe with a liquid hole punched in the upper part and a solid steel rod as the tie rod assembly in the lower part. This increases the overall tensile strength of the tie rod assembly while retaining the liquid channel. In addition, in order to avoid the tie rod assembly being subjected to a force exceeding the tensile strength limit of the tie rod assembly and causing a breakage accident when encountering bottom blockage, the present invention adopts a shearable structure in the form of a shear pin, which has a simple structure and is available in a variety of types. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of the installation of an expansion device for an expansion tube of the present invention;

[0020] Figure 2 is a schematic diagram of a tie rod assembly in an embodiment of the present invention;

[0021] Figure 3 is a schematic diagram of connecting an oil pipe in an embodiment of the present invention;

[0022] Figure 4 is a schematic diagram of a second connecting pipe clamp in an embodiment of the present invention;

[0023] Figure 5 is a schematic diagram of a first connecting pipe clamp in an embodiment of the present invention;

[0024] Figure 6 is a schematic diagram of a limit block in an embodiment of the present invention;

[0025] Figure 7 is a schematic diagram of a pull rod in an embodiment of the present invention;

[0026] Figure 8 This is a schematic diagram of a connection of a limiting structure in an embodiment of the present invention;

[0027] Fig. 9 is another schematic diagram of the connection of the limiting structure in an embodiment of the present invention;

[0028] In the figure: 0, expansion tube; 01, flaring; 1, expansion cone assembly; 2, expansion tube bottom plug; 3, sealing tube; 4, limiting structure; 41, wedge-shaped claw; 42, wedge-shaped groove; 43, limiting protrusion; 5, oil inlet pipe; 6, tie rod assembly; 61, connecting oil pipe; 611, liquid outlet; 62, tie rod; 63, first connecting pipe clamp; 64, second connecting pipe clamp; 7, limiting block; 8, shearable structure; 81, shear pin; 82, pin hole;. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] like Figure 1 As shown, an expansion device for an expansion pipe includes an expansion cone assembly 1, an expansion pipe bottom plug 2 and a sealing pipe 3, the expansion pipe bottom plug 2 is used to connect with the sealing pipe 3, the expansion cone assembly 1 is used to connect in the front part of the expansion pipe 0 end expansion 01, the expansion pipe bottom plug 2 is used to slide in the rear part of the expansion pipe 0 end expansion 01, and a limiting structure 4 is provided between the expansion pipe bottom plug 2 and the expansion pipe 0 to prevent the expansion pipe bottom plug 2 from sliding away from the expansion cone assembly 1, and an oil inlet pipe for inputting pressure oil into the sealing pipe 3 is sealed and connected to the expansion cone assembly 1 5. A pull rod assembly 6 is connected to the oil inlet pipe 5. The pull rod assembly 6 passes through the axial hole 21 opened on the bottom plug 2 of the expansion tube and then extends into the sealing tube 3. A limit block 7 is arranged at one end of the pull rod assembly 6 extending into the sealing tube 3. The width of the limit block 7 is larger than the aperture of the axial hole 21 opened on the bottom plug 2 of the expansion tube. The pull rod assembly 6 is used to pull the limit block 7 to slide along the sealing tube 3. The limit block 7 and the pull rod assembly 6 are connected by a shearable structure 8. The shear strength of the shearable structure 8 is less than the safety threshold, and the safety threshold is determined according to the tensile strength of the expansion tube 0.

[0031] The implementation method or working principle is as follows: the expansion tube 0 is expanded 01, the expansion cone assembly 1, the expansion tube bottom plug 2 and the sealing tube 3 together form a pressurized chamber, the oil inlet pipe 5 injects oil pressure into the pressurized chamber, and pushes the expansion cone assembly 1 along the expansion tube 0 toward the wellhead to complete the expansion construction operation, and at the same time, the pull rod assembly 6 drives the limit block 7 to run along the sealing tube 3 toward the wellhead. When the expansion construction operation is completed, the oil inlet pipe 5 and the pull rod assembly 6 are continuously lifted up, which will cause the limit block 7 to press against the expansion tube bottom plug 2, driving the expansion tube bottom plug 2 Together, they slide out in the expansion direction of the expansion cone assembly 1, and the expansion tube bottom plug 2 and the sealing tube 3 connected thereto are salvaged underground, and the underground integrated expansion and salvage work is completed. When the expansion and salvage encounters resistance, such as the well wall causing the oil inlet pipe 5 to be pulled out and the tension exceeds the set release tension of the limit block 7, if the tension is greater than the shear strength safety threshold of the shearable structure 8, such as the threshold is 60% of the expansion tube 0 tensile strength, the shearable structure 8 is sheared off by itself, and the limit block 7 and the pull rod assembly 6 are automatically disengaged. The limit block 7 and the expansion tube bottom plug 2 are left underground together and are salvaged again by a special salvage tool. In this way, the expansion tube bottom plug 2 can be salvaged smoothly without the above-mentioned obstacles, and the expansion tube bottom plug 2 can be safely handled. If the above-mentioned situation makes it difficult to salvage, the occurrence of safety accidents can be avoided.

[0032] According to the above working principle, some preferred implementation structures and methods are provided, such as Figure 1 As shown, the tie rod assembly 6 includes a connecting oil pipe 61, a plurality of tie rods 62, a first connecting pipe clamp 63 and Figure 2 or Figure 4 The second connecting pipe hoop 64 is shown as Figure 1 or Figure 2 As shown, a plurality of tie rods 62 are connected to each other through a first connecting pipe hoop 63 to form a long rod. Figure 1 As shown, one end of the connecting oil pipe 61 is connected to the oil inlet pipe 5, and the other end is connected to one end of the long rod through the second connecting pipe hoop 64, and the other end of the long rod is connected to the limit block 7 through the shearable structure 8. The connecting oil pipe 61 can be used to connect with the oil inlet pipe 5 and to seal with the expansion cone assembly 1, and can be used for the connection of multiple wells to improve its versatility. The way that multiple tie rods 62 are connected through the first connecting pipe hoop 63 can be used to match the expansion distance setting of the expansion pipe 0, which is convenient for installation and use.

[0033] The shearable structure 8 includes: Figure 2 The shear pin 81 shown and Figure 6The pin hole 82 shown in the figure matches the shear pin 81, and the pin hole 82 is arranged on the limit block 7 and the pull rod 62 connected to the limit block 7. The shear pin 81 is a commonly used shearable structure 8, which has a simple structure and reliable operation. Shear pins 81 of various strengths are highly marketed and easy to purchase. Those skilled in the art should be able to think of other shearable structures 8 that meet the above functions, such as the connecting block that cannot withstand the above pulling force and is directly pulled off, which can also be used in the above device and should be covered within the scope of protection of the present invention.

[0034] like Figure 1 As shown, the diameter of the connecting oil pipe 61 is larger than the diameter of the pull rod 62, and the pull rod 62 is a solid pipe. The solid pipe can increase the pulling force of the pipe fitting on the expansion pipe bottom plug 2.

[0035] The length of the sealing tube 3 is greater than the expansion length of the expansion tube 0. This ensures that the expansion tube 0 is fully expanded.

[0036] like Figure 3 As shown, the two ends of the connecting oil pipe 61 are connected to the Figure 4 The second connecting pipe clamp 64 and Figure 1 The oil inlet pipe 5 is connected. This facilitates the detachable connection between the two.

[0037] like Figure 2 As shown, the connecting oil pipe 61 is provided with a liquid outlet 611. Referring to the existing settings, those skilled in the art should be able to imagine that the expansion cone assembly 1 should be provided with a sealing groove, and the sealing groove is connected to a sealing ring, which is used to seal between the expansion cone assembly 1 and the expansion pipe 0. The liquid outlet 611 is used for the oil to enter the expansion cone assembly 1. Figure 1 In the cavity between the expansion cone assembly 1 and the sealing tube 3 shown, the sealing ring can ensure that the oil entering does not leak, resulting in a reduction in the pressure on the expansion cone assembly 1.

[0038] The end of the limiting structure 4 away from the expansion cone assembly 1 is connected to the expansion pipe 0 end flare 01 through a seal. This ensures that the oil entering the cavity does not leak, resulting in a reduction in the pressure on the expansion cone assembly 1.

[0039] See also Figure 8 As shown, the limiting structure 4 includes a wedge-shaped claw 41 and a wedge-shaped groove 42, the wedge-shaped groove 42 and the wedge-shaped claw 41 are respectively arranged on the expansion pipe 0 end flare 01 and the expansion pipe bottom plug 2, and the wedge-shaped claw 41 can move along the wedge-shaped groove 42 to approach the expansion pipe 0 end flare 01 and the expansion pipe bottom plug 2. Figure 1 The expansion cone assembly 1 shown slides in one direction and is restricted from sliding in the opposite direction.

[0040] See also Fig. 9 and Figure 1As shown, the limiting structure 4 includes a limiting protrusion 43, which is arranged on the expansion pipe 0 end flare 01, and is used to limit the expansion pipe bottom plug 2 from sliding away from the expansion cone assembly 1. The limiting protrusion 43 needs to be polished off by passing a milling pipe after the expansion construction of the expansion pipe is completed.

[0041] For specific usage, see Figure 1-9 As shown, the upper and lower end surfaces of the expansion cone assembly 1 at the flared opening 01 at the bottom end of the expansion tube can be connected to the oil inlet pipe 5 and the connecting oil pipe 61 respectively by threads, and then the center hole of the expansion tube bottom plug 2 is passed through a long rod, connected to the limit block 7, and the sealing tube 3 is connected to the expansion tube bottom plug 2 by threads. Finally, the whole device is lowered from the wellhead through the pipe lowering machine to the position to be expanded. The hydraulic power is transmitted from the tool oil pipe through the oil inlet pipe 5 and the fluid connecting the oil pipe 61 from the liquid outlet 611 to the closed cavity, prompting the expansion cone assembly 1 to drive the pull rod assembly 6 and the limit block 7 to move upward to the end of the to-be-expanded section of the expansion tube 0, which is generally the prefabricated bell mouth at its upper end. The expansion is completed, and the expansion tube 0 is tightly sealed with the casing in the well through the sealing gasket of its outer ring; the oil inlet pipe 5 is depressurized, and the oil inlet pipe 5 is further lifted, driving the limit block 7 to continue to move upward and contact with the bottom plug 2 of the expansion tube, and continue to lift the oil pipe. The limit block 7 pushes the bottom plug 2 of the expansion tube to move toward the wellhead, and finally brings it out of the wellhead, completing the expansion and catching operation, with good straightening effect.

[0042] Those skilled in the art should be able to imagine that the shape and structure of the limit block 7 can be various, such as a tubular structure, and the sealing tube 3 can be a common sand settling tube, which is formed in the form of a sealing connection at its end through a plug.

[0043] It is also possible to provide a sliding seal between the expansion tube bottom plug 2 and the expansion tube 0 and to provide a sealing pad at the position where the limit block 7 and the expansion tube bottom plug 2 abut against each other, so as to achieve sealing during expansion and reduce the size of the sealing tube.

[0044] It should be noted that the terms "first", "second" etc. in the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged in appropriate circumstances, so that the embodiments of the present application described here. In the present application, the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", "middle", "vertical", "horizontal", "lateral", "longitudinal" etc. are based on the orientation or positional relationship shown in the accompanying drawings.

[0045] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. 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 invention. In this specification, the schematic representation of the above terms does not necessarily refer 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.

[0046] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. An expansion device for an expansion pipe, comprising an expansion cone assembly (1), an expansion pipe bottom plug (2) and a sealing pipe (3), wherein the expansion pipe bottom plug (2) is used to be connected to the sealing pipe (3), the expansion cone assembly (1) is used to be connected to the front part of the expansion pipe (0) end flare (01), the expansion pipe bottom plug (2) is used to be slidably connected to the rear part of the expansion pipe (0) end flare (01), and a limiting structure (4) is provided between the expansion pipe bottom plug (2) and the expansion pipe (0) to prevent the expansion pipe bottom plug (2) from sliding in a direction away from the expansion cone assembly (1), characterized in that: The expansion cone assembly (1) is sealedly connected to an oil inlet pipe (5), and the oil inlet pipe (5) is used to input pressure oil into the sealing tube (3). The oil inlet pipe (5) is connected to a pull rod assembly (6), and the pull rod assembly (6) extends into the sealing tube (3) after passing through an axial hole (21) opened on the bottom plug (2) of the expansion tube. A limit block (7) is arranged at one end of the pull rod assembly (6) extending into the sealing tube (3). The width of the limit block (7) is greater than the aperture of the axial hole (21) opened on the bottom plug (2) of the expansion tube. The pull rod assembly (6) is used to pull the limit block (7) to slide along the sealing tube (3). The limit block (7) and the pull rod assembly (6) are connected by a shearable structure (8). The shear strength of the shearable structure (8) is less than a safety threshold, and the safety threshold is determined according to the tensile strength of the expansion tube (0).

2. The expansion device for an expansion pipe according to claim 1, characterized in that: The tie rod assembly (6) comprises a connecting oil pipe (61), a plurality of tie rods (62), a first connecting pipe hoop (63) and a second connecting pipe hoop (64); the plurality of tie rods (62) are connected to each other via the first connecting pipe hoop (63) to form a long rod; one end of the connecting oil pipe (61) is connected to the oil inlet pipe (5), and the other end is connected to one end of the long rod via the second connecting pipe hoop (64); the other end of the long rod is connected to the limit block (7) via the shearable structure (8).

3. An expansion device for an expansion pipe according to claim 1 or 2, characterized in that: The shearable structure (8) comprises a shearing pin (81) and a pin hole (82), wherein the pin hole (82) matches the shearing pin (81), and the pin hole (82) is arranged on a limit block (7) and a pull rod (62) connected to the limit block (7).

4. The expansion device for an expansion pipe according to claim 2, characterized in that: The diameter of the connecting oil pipe (61) is greater than the diameter of the pull rod (62), and the pull rod (62) is a solid pipe.

5. The expansion device for an expansion pipe according to claim 2, characterized in that: The length of the sealing tube (3) is greater than the expansion length of the expansion tube (0).

6. The expansion device for an expansion pipe according to claim 2, characterized in that: Both ends of the connecting oil pipe (61) are connected to the second connecting pipe clamp (64) and the oil inlet pipe (5) respectively through threads.

7. The expansion device for an expansion pipe according to claim 1, characterized in that: The connecting oil pipe (61) is provided with a liquid outlet hole (611), the expansion cone assembly (1) is provided with a sealing groove, the sealing groove is connected to a sealing ring, and the sealing ring is used for sealing between the expansion cone assembly (1) and the expansion pipe (0).

8. The expansion device for an expansion pipe according to claim 1, characterized in that: The end of the limiting structure (4) away from the expansion cone assembly (1) is connected to the expansion pipe (0) end flare (01) via a sealing member.

9. An expansion device for an expansion pipe according to claim 1 or 8, characterized in that: The limiting structure (4) comprises a wedge-shaped claw (41) and a wedge-shaped groove (42), wherein the wedge-shaped groove (42) and the wedge-shaped claw (41) are respectively arranged on the expansion pipe (0) end flare (01) and the expansion pipe bottom plug (2), and the wedge-shaped claw (41) can slide along the wedge-shaped groove (42) in a direction close to one end of the expansion cone assembly (1), and is restricted from sliding in the opposite direction of the direction.

10. An expansion device for an expansion pipe according to claim 1 or 8, characterized in that: The limiting structure (4) comprises a limiting protrusion (43), which is arranged on the expansion pipe (0) end flare (01) and is used to limit the expansion pipe bottom plug (2) from sliding in a direction away from the expansion cone assembly (1).

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