Double sleeve

Abstract

The application relates to a double-layer sleeve and belongs to the technical field of pipeline manufacturing. The double-layer sleeve comprises a sleeve assembly and joint assemblies arranged at two ends of the sleeve assembly, the sleeve assembly comprises an inner pipe and an outer pipe, the joint assemblies are fixedly connected with the outer pipe, the joint assemblies are in sliding connection with the inner pipe, the outer pipe is arranged outside the inner pipe, a buffer space is formed between the outer pipe and the inner pipe, and the inner pipe can slide axially along the outer pipe. When the outer pipe is subjected to a shearing force, the buffer space is used for reducing the influence of deformation of the outer pipe on the inner pipe. By arranging the inner pipe and the outer pipe to form the buffer space, the buffer space can play a buffering role when the outer pipe is subjected to a shearing force, and the shearing deformation of the inner pipe can be effectively relieved.

Description

Technical Field

[0001] This application belongs to the field of pipeline manufacturing technology, and in particular relates to a double-layer sleeve. Background Technology

[0002] With the continuous growth of global energy demand, the exploitation of traditional oil and gas resources is gradually failing to meet market demand. Unconventional oil and gas resources, such as shale gas, tight sandstone gas, and coalbed methane, are gradually becoming important energy supplements due to their abundant reserves. However, these unconventional oil and gas reservoirs typically have low permeability and low porosity, making effective extraction difficult using traditional methods. Therefore, developing efficient extraction technologies has become crucial for the development of unconventional oil and gas resources. Hydraulic fracturing is a technology that injects high-pressure fluid into the formation to fracture the rock, creating a fracture network, thereby improving oil and gas flowability and recovery rates.

[0003] Existing hydraulic fracturing technology includes steps such as wellbore installation, segmented isolation, and fracturing fluid injection. When installing the wellbore, it is necessary to select casing and insert the casing segments into the wellbore one by one, and then connect the segments of the casing using casing joints.

[0004] However, traditional casing is mostly a single-layer casing structure, which makes it prone to shear deformation during fracturing, thus affecting operational efficiency. Summary of the Invention

[0005] This application provides a double-layer casing to solve the problem that single-layer casing structures in the prior art are prone to shear deformation during fracturing, thereby affecting operational efficiency.

[0006] In a first aspect, this application provides a double-layer sleeve, including a sleeve assembly and connector assemblies disposed at both ends of the sleeve assembly, wherein the sleeve assembly includes an inner tube and an outer tube.

[0007] The connector assembly is fixedly connected to the outer tube, and the connector assembly is slidably connected to the inner tube. The outer tube is disposed outside the inner tube, and a buffer space is formed between the outer tube and the inner tube. The inner tube can slide along the axial direction of the outer tube.

[0008] When the outer tube is subjected to shear force, the buffer space is used to reduce the impact of the deformation of the outer tube on the inner tube.

[0009] In the embodiments provided in this application, the connector assembly includes a connector and a first connecting ring.

[0010] The inner wall of the connector is slidably connected to the inner tube. The first connecting ring is disposed on the connector. The end of the first connecting ring away from the connector is connected to the outer tube. The first connecting ring is used to fix the connector and the outer tube.

[0011] In the embodiments provided in this application, the connector assembly further includes a second connecting ring.

[0012] The second connecting ring is disposed on the inner side wall of the connector, and a groove is formed between the second connecting ring and the connector, and at least part of the inner tube is slidably connected to the groove.

[0013] In the embodiments provided in this application, a fixing block is provided on the outer side wall of the second connecting ring, and a limiting groove is provided on the inner tube. The fixing block is slidably connected to the limiting groove, and the fixing block is used to prevent the part of the inner tube located in the groove from sliding out of the groove.

[0014] In the embodiments provided in this application, the fixing block is located within the groove.

[0015] In the embodiments provided in this application, the length of the slide groove is greater than the length of the limiting groove.

[0016] In the embodiments provided in this application, a sealing layer is provided on the contact surface between the first connecting ring and the outer tube.

[0017] In the embodiments provided in this application, the sealing layer is a rubber layer.

[0018] In the embodiments provided in this application, the inner tube is further provided with at least one through hole, which is used for communication between the inner cavity of the inner tube and the buffer space.

[0019] In the embodiments provided in this application, the thickness of the outer tube is greater than the thickness of the inner tube.

[0020] The double-layer sleeve provided in this application includes a sleeve assembly and connector assemblies disposed at both ends of the sleeve assembly. The sleeve assembly includes an inner tube and an outer tube. The connector assemblies are fixedly connected to the outer tube and slidably connected to the inner tube. The outer tube is disposed outside the inner tube, forming a buffer space between the outer tube and the inner tube. The inner tube can slide along the axial direction of the outer tube. When the outer tube is subjected to shear force, the buffer space is used to reduce the impact of the deformation of the outer tube on the inner tube. By setting the inner and outer tubes to form a buffer space, when the outer tube is subjected to shear force, the buffer space can play a buffering role, effectively alleviating the shear deformation of the inner tube. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of the embodiments of this application.

[0022] Figure 1 A schematic diagram of the full cross-sectional structure of the double-layer sleeve provided in the embodiments of this application;

[0023] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0024] Figure 3 This is a schematic diagram of the structure of the double-layer sleeve provided in the embodiments of this application;

[0025] Figure 4 This is a half-sectional structural diagram of the double-layer sleeve provided in an embodiment of this application.

[0026] Figure label:

[0027] 100-Sleeve Assembly;

[0028] 110-Inner tube;

[0029] 120 - Outer tube;

[0030] 130 - Limiting groove;

[0031] 140 - Through hole;

[0032] 200-Connector assembly;

[0033] 210-Connector;

[0034] 220 - First connecting ring;

[0035] 230 - Second connecting ring;

[0036] 240-Groove;

[0037] 250-Fixed Block;

[0038] 300-Buffer Space;

[0039] 400 - Sealing layer.

[0040] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0042] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those illustrated or described herein.

[0043] In this application, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0044] In the description of the embodiments of this application, it should be understood that the terms "inner", "outer", "upper", "bottom", "front", "rear", etc., indicate the orientation or positional relationship (if any) based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0045] Hydraulic fracturing technology involves injecting high-pressure liquid into underground rock formations to create fractures, thereby increasing the flow channels for oil and gas and improving the recovery rate of oil and gas.

[0046] The main steps of hydraulic fracturing technology include drilling, casing and cementing, perforation, injection of fracturing fluid, and injection of proppant. During fracturing fluid injection, a wellbore needs to be installed inside the well to allow the fracturing fluid to flow to a predetermined location. When installing the wellbore, casing needs to be selected and inserted section by section into the wellbore, then connected using casing joints.

[0047] However, during the fracturing process, natural fractures and faults are easily activated, which in turn causes formation slippage. This results in the casing being subjected to loads exceeding the strength limit of its material, leading to shear deformation or breakage of the casing.

[0048] Especially during the multi-stage fracturing process of shale gas horizontal wells, casing deformation has always been a problem that plagues the efficiency of field operations. Casing deformation not only reduces the reservoir utilization rate, but also significantly increases the maintenance cost of the wellbore, thus seriously restricting the efficient development of shale gas.

[0049] From an engineering perspective, the main strategy for addressing casing shear deformation is to optimize the parameters of the casing and cement sheath. However, field engineering practice shows that this method is not very effective and has failed to significantly alleviate the casing shear deformation problem. This may be because traditional single-layer casing structures have inherent limitations when dealing with high-stress conditions in complex geological environments, making them prone to shear deformation during fracturing, thus affecting operational efficiency.

[0050] This application utilizes a double-layer sleeve structure, and through the special design of the double-layer sleeve, it effectively alleviates the problem of shear deformation of the inner tube. The embodiments of this application will be further described below with reference to the accompanying drawings.

[0051] in, Figure 1 This is a schematic diagram of the full cross-sectional structure of the double-layer sleeve provided in the embodiment of this application. Figure 2 for Figure 1 Enlarged view of point A in the middle. Figure 3 This is a schematic diagram of the structure of the double-layer sleeve provided in an embodiment of this application. Figure 4 This is a half-sectional structural diagram of the double-layer sleeve provided in an embodiment of this application.

[0052] Combination Figure 1 , Figure 3 and Figure 4 As shown, this application provides a double-layer sleeve, including a sleeve assembly 100 and connector assemblies 200 disposed at both ends of the sleeve assembly 100. The sleeve assembly 100 includes an inner tube 110 and an outer tube 120.

[0053] The connector assembly 200 is fixedly connected to the outer tube 120 and slidably connected to the inner tube 110. The outer tube 120 is located outside the inner tube 110, and a buffer space 300 is formed between the outer tube 120 and the inner tube 110. The inner tube 110 can slide along the axial direction of the outer tube 120.

[0054] When the outer tube 120 is subjected to shear force, the buffer space 300 is used to reduce the impact of the deformation of the outer tube 120 on the inner tube 110.

[0055] By setting up an inner tube 110 and an outer tube 120 to form a buffer space 300, when the outer tube 120 is subjected to shear force, the buffer space 300 can play a buffering role and effectively alleviate the shear deformation of the inner tube 110.

[0056] The inner tube 110 and the outer tube 120 can be made of materials such as carbon steel, low alloy steel, stainless steel and nickel-based alloys to meet the harsh conditions such as high temperature, high pressure and chemical corrosion that occur during the fracturing process.

[0057] In this embodiment, the thickness of the outer tube 120 is greater than the thickness of the inner tube 110. Specifically, the wall thickness of the outer tube 120 is greater than the wall thickness of the inner tube 110. When subjected to shear force, the outer tube 120 experiences a larger force. Therefore, providing a thicker outer tube 120 can increase the toughness of the outer tube 120 and increase its resistance to deformation.

[0058] For example, the outer diameter of the outer tube 120 is 139.7 mm, the outer diameter of the inner tube 110 is 105 mm, the minimum inner diameter of the inner tube 110 is 95 mm, and the width of the bridge plug entering the inner tube 110 during fracturing is 85 mm. A 10 mm margin exists between the bridge plug and the wall of the inner tube 110 to allow for smooth insertion of the bridge plug. The coupling used for casing with a maximum outer diameter of 149.7 mm but less than 139 mm has an outer diameter of 153.7 mm, conforming to API standards. API standards refer to standards for equipment used in the oil and gas industry.

[0059] The bottom of the upper connector assembly 200 is used to connect the inner tube 110 and the outer tube 120, and the top of the connector assembly 200 is used to connect to the top of the previous set of double-layer sleeves, and so on, so that the double-layer sleeves can be extended to the location where fracturing is required.

[0060] The connector assemblies 200 at both ends are fixedly connected to the outer tube 120, and the inner tube 110 is located inside the outer tube 120. Both ends of the inner tube 110 are slidably connected to the connector assembly 200. A closed buffer space 300 is formed between the inner tube 110 and the outer tube 120. When the outer tube 120 is subjected to shear force, the buffer space 300 can alleviate the shear force of the outer tube 120. When the buffer space 300 cannot alleviate the shear force, the inner tube 110, due to its sliding design, will first tilt, then bend, and finally deform. Therefore, it can effectively alleviate the shear deformation of the inner tube 110 and ensure the smooth passage of the bridge plug.

[0061] Combination Figure 1 and Figure 2 As shown in the embodiments provided in this application, the connector assembly 200 includes a connector 210 and a first connecting ring 220.

[0062] The inner wall of the connector 210 is slidably connected to the inner tube 110. The first connecting ring 220 is disposed on the connector 210. The end of the first connecting ring 220 away from the connector 210 is connected to the outer tube 120. The first connecting ring 220 is used to fix the connector 210 and the outer tube 120.

[0063] The connector 210 is annular in shape, and the first connecting ring 220 is sleeved on the middle of the connector 210. The bottom of the first connecting ring 220 is located outside the outer tube 120 and is fixedly connected to the outside of the outer tube 120. The cross-sectional shape of the first connecting ring 220 is L-shaped to accommodate situations where the outer tube 120 and the connector 210 are not on the same plane.

[0064] Combined Figure 1 and Figure 2 As shown in the embodiments provided in this application, the connector assembly 200 further includes a second connecting ring 230.

[0065] The second connecting ring 230 is disposed on the inner wall of the connector 210, and a groove 240 is formed between the second connecting ring 230 and the connector 210, and at least part of the inner tube 110 is slidably connected to the groove 240.

[0066] The second connecting ring 230 has an external thread on its outer side wall at the top, and the connector 210 has an internal thread on its inner side wall. The engagement of the internal and external threads secures the second connecting ring 230 inside the connector 210. The width of the thread is one-third of the height of the second connecting ring 230, and the remaining portion forms a groove 240 between the outer side wall of the second connecting ring 230 and the inner side wall of the connector 210.

[0067] For example, the groove 240 is formed by the inward indentation of the inner sidewall of the bottom of the connector 210. The top of the inner tube 110 is inserted into the groove 240, and the inner tube 110 can slide along the groove 240 to ensure that the inner tube 110 can undergo relative displacement when subjected to shear force, thereby ensuring that the inner tube 110 has tilt buffer and avoiding direct deformation of the inner tube 110.

[0068] In the embodiments provided in this application, a fixing block 250 is provided on the outer side wall of the second connecting ring 230, and a limiting groove 130 is provided on the inner tube 110. The fixing block 250 is slidably connected to the limiting groove 130. The fixing block 250 is used to prevent part of the inner tube 110 located in the sliding groove 240 from sliding out of the sliding groove 240.

[0069] The fixing blocks 250 are arranged circumferentially along the outer wall of the second connecting ring 230, specifically, multiple fixing blocks 250 are arranged at intervals around the second connecting ring 230. The number of limiting grooves 130 is the same as the number of fixing blocks 250.

[0070] In the embodiments provided in this application, the fixing block 250 is located within the slide groove 240. When the inner tube 110 tilts, it may slide out of the slide groove 240 during its sliding process. Therefore, the cooperation between the limiting groove 130 and the fixing block 250 prevents the inner tube 110 from sliding out of the slide groove 240, thus avoiding the situation where the inner tube 110 separates from the connector 210.

[0071] For example, for the installation of the fixing block 250, multiple slots can be set on the outer side wall of the second connecting ring 230, and some of the fixing blocks 250 can be inserted into the slots.

[0072] In the embodiments provided in this application, the length of the slide groove 240 is greater than the length of the limiting groove 130. This is to ensure that the inner tube 110 can be completely disposed inside the limiting groove 130, avoiding the limiting groove 130 from being too long and causing part of the limiting groove 130 to extend out of the slide groove 240, and preventing the inner cavity of the inner tube 110 from communicating with the buffer space 300 through the limiting groove 130.

[0073] In the embodiments provided in this application, a sealing layer 400 is provided on the contact surface between the first connecting ring 220 and the outer tube 120. The sealing layer 400 is provided to prevent outside air from entering the buffer space 300.

[0074] In the embodiments provided in this application, the sealing layer 400 is a rubber layer.

[0075] In the embodiments provided in this application, the inner tube 110 is also provided with at least one through hole 140, which is used for communication between the inner cavity of the inner tube 110 and the buffer space 300.

[0076] In the production process of the double-layer sleeve of this application, the fixing block 250 is first connected to the second connecting ring 230 and the inner tube 110, and then the connector 210 is threadedly connected to the second connecting ring 230, so that the inner tube 110 can only slide axially and cannot produce radial displacement.

[0077] The through hole 140 can effectively prevent the air in the buffer space 300 from squeezing the inner tube 110 when the outer tube 120 undergoes shear deformation. The through hole 140 can transport the gas in the buffer space 300 to the inner cavity of the inner tube 110, thereby balancing the pressure in the buffer space 300 and preventing the inner tube 110 from deforming under the action of air pressure.

[0078] Furthermore, in actual working conditions, the fracturing fluid used during fracturing can also enter the buffer space 300 through the through hole 140, which can also balance the pressure on both sides of the inner tube 110, without the need to inject fracturing fluid into the buffer space 300 in advance.

[0079] Therefore, the double-layer sleeve provided in this application includes a sleeve assembly 100 and connector assemblies 200 disposed at both ends of the sleeve assembly 100. The sleeve assembly 100 includes an inner tube 110 and an outer tube 120. The connector assembly 200 is fixedly connected to the outer tube 120 and slidably connected to the inner tube 110. The outer tube 120 is disposed outside the inner tube 110, and a buffer space 300 is formed between the outer tube 120 and the inner tube 110. The inner tube 110 can slide along the axial direction of the outer tube 120. When the outer tube 120 is subjected to shear force, the buffer space 300 is used to reduce the impact of the deformation of the outer tube 120 on the inner tube 110. By setting the inner tube 110 and the outer tube 120 to form the buffer space 300, when the outer tube 120 is subjected to shear force, the buffer space 300 can play a buffering role, effectively alleviating the shear deformation of the inner tube 110.

[0080] Furthermore, the inner tube 110 can slide axially. When the fault slip is induced by multi-stage fracturing, and the outer tube 120 is sheared, the inner tube 110 first tilts, then bends, and finally deforms, thereby effectively ensuring the smooth passage of the bridge plug.

[0081] The technical solutions of this application have been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it is readily understood by those skilled in the art that the scope of protection of this application is obviously not limited to these specific embodiments. The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0082] Generally speaking, terms should be understood at least in part by their use in context. For example, at least in part by context, the term "one or more" as used in the text can be used to describe any feature, structure, or characteristic of the singular meaning, or a combination of features, structures, or characteristics of the plural meaning. Similarly, at least in part by context, terms such as "one" or "multiple" can also be understood to convey either singular or plural usage.

[0083] It should be readily understood that the terms “on,” “above,” and “on top of” in this disclosure should be interpreted in the broadest possible sense, such that “on” means not only “directly on something” but also “on something” with an intermediate feature or layer therebetween, and that “above” or “on top of” means not only “on top of something” but also “on top of something” without an intermediate feature or layer therebetween (i.e., directly on something).

Claims

1. A double-layered cannula, characterized by, The application relates to a sleeve assembly (100) and a joint assembly (200) arranged at both ends of the sleeve assembly (100), wherein the sleeve assembly (100) comprises an inner tube (110) and an outer tube (120); the joint assembly (200) is fixedly connected with the outer tube (120), the joint assembly (200) is slidably connected with the inner tube (110), the outer tube (120) is arranged outside the inner tube (110), a buffer space (300) is formed between the outer tube (120) and the inner tube (110), and the inner tube (110) can slide axially along the outer tube (120); when the outer tube (120) is subjected to a shearing force, the buffer space (300) is used for reducing the influence of deformation of the outer tube (120) on the inner tube (110); the joint assembly (200) comprises a joint (210) and a first connecting ring (220); an inner side wall of the joint (210) is slidably connected with the inner tube (110), the first connecting ring (220) is arranged on the joint (210), one end of the first connecting ring (220) away from the joint (210) is connected with the outer tube (120), and the first connecting ring (220) is used for fixing the joint (210) and the outer tube (120); the joint assembly (200) further comprises a second connecting ring (230); the second connecting ring (230) is arranged on the inner side wall of the joint (210), a sliding groove (240) is formed between the second connecting ring (230) and the joint (210), and at least part of the inner tube (110) is slidably connected with the sliding groove (240); a fixing block (250) is arranged on an outer side wall of the second connecting ring (230), a limiting groove (130) is arranged on the inner tube (110), the fixing block (250) is slidably connected with the limiting groove (130), and the fixing block (250) is used for preventing part of the inner tube (110) located in the sliding groove (240) from sliding out of the sliding groove (240).

2. The dual-layer sleeve of claim 1, wherein, The fixing block (250) is located in the sliding groove (240).

3. The dual-layer sleeve of claim 2, wherein, The length of the sliding groove (240) is greater than the length of the limiting groove (130).

4. Double sleeve according to any of claims 1-3, characterized in that A sealing layer (400) is arranged on the contact surface between the first connecting ring (220) and the outer tube (120).

5. The dual-layer sleeve of claim 4, wherein, The sealing layer (400) is a rubber layer.

6. The dual-layer sleeve of any one of claims 1-3, wherein, At least one through hole (140) is further arranged on the inner tube (110), and the through hole (140) is used for communication between the inner cavity of the inner tube (110) and the buffer space (300).

7. The dual-layer sleeve of any of claims 1-3, wherein, The thickness of the outer tube (120) is greater than the thickness of the inner tube (110).

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