Expansion rubber sleeve unit of packer

Abstract

The invention discloses an expansion rubber sleeve unit of a packer, and relates to the technical field of downhole tools. The unit comprises a base, an inner rubber sleeve, an outer rubber sleeve, a key, a key sleeve and a fiber layer. Two ends of the inner rubber sleeve are vulcanized and fixed on the base, and the middle is not vulcanized to cooperate with the pressure transmission hole to transmit pressure; the outer rubber sleeve is fixed on the key sleeve; and the key is arranged in the key slot of the base and is locked by the key sleeve. The fiber layer is wound on the keys in a staggered mode and located between the inner rubber sleeve and the outer rubber sleeve, and is bent in the middle of the inner rubber sleeve to reserve expansion space. The high-strength fiber layer is used for limiting excessive expansion of the inner rubber barrel, and the shoulder protrusion phenomenon is effectively prevented; through the design of the metal framework and the inner and outer rubber barrels with different hardness, the structural stability and the pressure-bearing sealing performance are remarkably improved. The rubber sleeve unit is simple in structure and supports multi-section series connection and modular assembly, and the production cost and the machining difficulty are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of downhole tools for oil and gas production, in particular to a packer inflatable rubber sleeve unit. BACKGROUND

[0002] The current energy system in China covers various types of energy such as oil, natural gas, nuclear energy and renewable energy. In order to regulate energy supply and demand, energy is usually stored in gas storage and energy storage. Once the well structure of these gas storage and energy storage is built, it is relatively fixed. In actual production operations, when the downhole tool needs to be removed due to damage, it often faces the strict restriction that the existing wellhead and upper wellbore structure cannot be damaged, and at the same time, effective sealing and protection of the production string must be achieved. At this time, the tubing packer becomes a key tool, which can establish temporary plugging without changing the original well structure, prevent gas leakage and isolate the corrosion environment, and provide protection for modernized completion and modification operations, and the rubber sleeve is the most core sealing component of the tubing packer.

[0003] The rubber sleeve used in the tubing packer on the market is mainly inflatable (expanding) rubber sleeve, and the internal reinforcing structure usually adopts laminated steel sheets, cord layers, or PIP pure rubber sleeve structure. However, these existing technical solutions have obvious limitations in actual application: 1. Rubber sleeve with laminated steel sheet reinforcement: its sealing performance is relatively poor, and the expansion ratio (expansion rate) is low, which is difficult to meet the high expansion demand of special well conditions.

[0004] 2. Rubber sleeve with cord layer reinforcement and PIP pure rubber sleeve: the length of a single expansion unit of this type of rubber sleeve is usually long. The long cylindrical structure will cause poor structural stability under high pressure environment. In addition, when facing different sealing pressure and axial force requirements, this long rubber sleeve structure is difficult to adapt flexibly, and often needs to be customized at high cost for specific working conditions, resulting in high use cost.

[0005] In summary, how to design and manufacture a tubing packer rubber sleeve that can balance high sealing performance, high structural stability, meet high expansion demand, adapt to different working conditions, and has low manufacturing cost is a technical problem to be solved in the current field. SUMMARY

[0006] The purpose of the present application is to provide a packer inflatable rubber sleeve unit to solve the problem of poor structural stability and easy "shoulder protrusion" phenomenon of the existing tubing packer rubber sleeve during setting. At the same time, the present application is also committed to solving the problem that the existing long rubber sleeve structure is difficult to balance high expansion ratio and high stability, and is difficult to flexibly adapt to different sealing pressure and axial force working conditions, resulting in high production and use cost.

[0007] The technical scheme of the present application is as follows: A packer expansion rubber tube unit comprises a base, an inner rubber tube, an outer rubber tube, a key, a key sleeve and a fiber layer. The inner rubber tube is fixed on the base; the key is arranged on the base; the fiber layer is wound on the key, and the fiber layer is located between the inner rubber tube and the outer rubber tube; the key sleeve is used for fixing the key; and the outer rubber tube is fixed on the key sleeve.

[0008] Further, both ends of the inner rubber tube are vulcanized and fixed on the base, and the middle part of the inner rubber tube is not vulcanized and connected with the base; and the outer rubber tube is vulcanized and fixed on the key sleeve.

[0009] Further, a key groove is formed in the outer wall of the base, and the key is inserted into the key groove; the key sleeve is sleeved on the base and fixed on the base by a screw to limit the displacement of the key.

[0010] Further, the key groove comprises a front row of key grooves and a rear row of key grooves which are distributed in an axial position offset manner; the fiber layer is interlaced and wound between the key installed in the front row of key grooves and the key installed in the rear row of key grooves, and the extension path of the fiber layer in the middle part of the inner rubber tube is curved.

[0011] Further, a gap is reserved between the key sleeve and the base, and the gap is used for accommodating the end part of the fiber layer and providing a moving space for the fiber layer when the fiber layer is deformed.

[0012] Further, the inner rubber tube is made of a first elastic material, and the outer rubber tube is made of a second elastic material, wherein the strength of the second elastic material is higher than that of the first elastic material.

[0013] Further, the fiber layer is made of a high-strength composite material; and the fiber layer is continuously laid by multiple layers of fibers.

[0014] Further, the base has a hollow tubular structure, and a pressure transmission hole is formed in the side wall of the base; the pressure transmission hole communicates the inner cavity of the base with the inner surface of the inner rubber tube, and the pressure transmission hole is located in the region of the inner rubber tube which is not vulcanized and connected with the base.

[0015] Further, a sealing ring is further included; the sealing ring is installed at the connection of the packer expansion rubber tube unit, and is used for preventing pressure leakage when the packer expansion rubber tube unit is connected with an adjacent component.

[0016] Further, the base extends in an axial direction, and one end of the base is provided with an internally threaded interface, and the other end is provided with an externally threaded interface, the internally threaded interface and the externally threaded interface being used to achieve series connection between multiple inflatable rubber sleeve units of the packer.

[0017] The beneficial effects of the present application compared with the prior art are: 1. The short rubber sleeve structure has high expansion and high structural stability, and the manufacturing difficulty is low. The short rubber sleeve unit structure is adopted in the present application, compared with the traditional long cylindrical rubber sleeve (such as PIP or cord rubber sleeve), the structure has high expansion and excellent structural stability, and is not easy to twist and lose stability. At the same time, the shorter unit structure design significantly reduces the processing and manufacturing difficulty, so that the production process is more controllable.

[0018] 2. The "shoulder protrusion" phenomenon is effectively prevented, and the pressure bearing is reliable. The high-strength fiber layer is used as a reinforcing layer in the present application, the fiber layer is located between the inner rubber sleeve and the outer rubber sleeve, can bear a large internal pressure and limit the excessive expansion of the inner rubber sleeve, thereby effectively preventing the "shoulder protrusion" phenomenon of the rubber sleeve during setting. The fiber layer adopts a specific staggered winding method, and a bending state is reserved in the middle section as an expansion space, which ensures that the outer rubber sleeve can reach the maximum expansion size without tearing when the rubber sleeve unit is set.

[0019] 3. Modular design, flexible response to working conditions and low cost. The inflatable rubber sleeve unit of the packer in the present application can be used in multiple connections. Users can flexibly set and install different numbers of rubber sleeve units according to different downhole working conditions (such as sealing pressure, well length) and work requirements. This modular splicing method avoids the high cost of customizing long rubber sleeves for specific working conditions, and has the significant advantages of low manufacturing cost, convenient installation and easy replacement.

[0020] 4. The layered material design optimizes the starting and wear resistance performance. The inner and outer rubber sleeves in the present application adopt different strength designs: the inner rubber sleeve adopts a high-elasticity material with lower strength, which is easy to expand rapidly under the action of the pressure transmission hole, meeting the high expansion ratio requirement; the outer rubber sleeve adopts a material with higher strength to meet the high load requirements of radial extrusion and axial shear during setting.

[0021] 5. Reliable inter-stage sealing. A sealing ring is installed at the connection of each rubber sleeve unit, which can effectively prevent pressure leakage between the rubber sleeve units, and ensure the overall sealing integrity when multiple units are used in series. BRIEF DESCRIPTION OF DRAWINGS

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in the embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0023] Figure 1 A schematic diagram of the overall structure of a packer expansion sleeve unit; Figure 2 An exploded schematic diagram of a packer expansion sleeve unit; Figure 3 for Figure 2 Enlarged view of point A in the middle; Figure 4 A cross-sectional view of a packer expansion sleeve unit; Figure 5 A schematic diagram showing the connection of multiple packer expansion sleeve units; Figure 6 This is a half-sectional view of the expansion setting of the packer expansion sleeve unit.

[0024] Reference numerals: 1-base, 2-inner rubber sleeve, 3-outer rubber sleeve, 4-key, 5-key sleeve, 6-fiber layer, 7-front keyway, 8-rear keyway, 9-pressure transmission hole, 10-sealing ring, 11-internal threaded interface, 12-external threaded interface, 13-ring post. Detailed Implementation

[0025] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0026] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0027] Example 1 This embodiment proposes a packer expansion sleeve unit, which is a short sleeve structure that can be used in multiple connections. It boasts a high expansion ratio, high structural stability, low manufacturing cost, convenient installation, and easy replacement. Structurally, it includes a base, sealing ring, inner sleeve, outer sleeve, key, key sleeve, and fiber layer. The inner sleeve is fixed to the base, and the outer sleeve is fixed to the key sleeve, both secured by vulcanization. The middle layer is a high-strength fiber layer. The two ends of the fiber layer fixed to the base are the key and the key sleeve.

[0028] In this embodiment, specifically, such as Figures 1-6 As shown, a packer expansion sleeve unit includes: a base 1, an inner sleeve 2, an outer sleeve 3, a key 4, a key sleeve 5, and a fiber layer 6. The inner sleeve 2 is fixed to the base 1; the key 4 is disposed on the base 1; the fiber layer 6 is wound around the key 4, and the fiber layer 6 is located between the inner sleeve 2 and the outer sleeve 3; the key sleeve 5 is used to fix the key 4; the outer sleeve 3 is fixed to the key sleeve 5.

[0029] In this embodiment, it should be noted that, to ensure the reliability and durability of the structure, the base 1, key sleeve 5, and metal connectors are all made of wear-resistant metal materials. The fiber layer 6 is made of high-strength composite material, capable of withstanding sufficiently large internal pressure. Its core function is to restrict the expansion of the inner rubber sleeve 2 without breaking it, until the rubber sleeve unit achieves setting, thereby effectively preventing the "shoulder protrusion" phenomenon commonly found in traditional packers. This structural design abandons the traditional high-strength metal support and compression method, utilizing high-strength fibers to withstand internal pressure, greatly improving the stability of the structure.

[0030] Furthermore, the two ends of the inner rubber cylinder 2 are vulcanized and fixed to the base 1, and the middle part of the inner rubber cylinder 2 is not vulcanized and connected to the base 1; the outer rubber cylinder 3 is vulcanized and fixed to the key sleeve 5.

[0031] Specifically, during manufacturing and assembly, the inner rubber tube 2 is first wrapped around the base 1 and fixed to it. In this step, special care must be taken to avoid clogging the pressure transmission hole 9. A certain distance is left at both ends of the inner rubber tube 2 to facilitate its vulcanization on the base 1, while the middle section remains unvulcanized. This is to facilitate pressure transmission through the pressure transmission hole 9, allowing the inner rubber tube 2 to expand smoothly. Furthermore, an annular post 13 is provided on the surface of the base 1 where it contacts the inner rubber tube 2. The purpose of this annular post 13 is to increase the contact area and friction between the base 1 and the inner rubber tube 2, further enhancing the stability of the connection. It should be noted that to prevent vulcanization adhesion, a special spray (special liquid) needs to be applied to the middle section of the inner surface of the inner rubber tube 2 before vulcanization to prevent the middle section from vulcanizing with the base 1. For the outer rubber tube 3, after the key sleeve 5 is installed, a ring of outer rubber tube 3 is spread on the key sleeve 5, and finally, the entire tube is vulcanized.

[0032] Furthermore, a keyway is provided on the outer wall of the base 1, and the key 4 is inserted into the keyway; the key sleeve 5 is fitted onto the base 1 and fixed to the base 1 by screws to limit the displacement of the key 4.

[0033] In this embodiment, key 4 is inserted into the keyway and then surrounds the base 1. Key sleeve 5 is installed and secured with screws (e.g., eight screws). The function of key sleeve 5 is not only to secure key 4, but also to prevent fibers from being pulled out from above key 4, thereby ensuring the integrity of the structure.

[0034] Furthermore, the keyway includes a front row of keyways 7 and a rear row of keyways 8 that are staggered along the axial direction; the fiber layer 6 is interleaved between the key 4 installed in the front row of keyways 7 and the key 4 installed in the rear row of keyways 8, and the extension path of the fiber layer 6 in the middle of the inner rubber cylinder 2 is curved.

[0035] That is, the fibers are arranged in a staggered pattern, one in front of the other, wrapped around the key 4, and then wound sequentially around the inner rubber sleeve 2 in a curved state in the middle. It should be noted that this winding method (e.g.) Figure 2 As shown, to allow sufficient expansion space for the fibers, the fibers exhibit a specific bending shape in the middle section of the rubber sleeve unit. The radius of curvature of this bending section corresponds to the maximum expansion dimension of the inner surface of the outer rubber sleeve 3 during setting (i.e., during setting, the fiber layer 6 is fully expanded and contacts the inner surface of the outer rubber sleeve 3). It should be understood that the fiber layer 6 is not limited to this one winding method; this winding method is only to allow sufficient expansion space for the fiber layer 6, and the fibers in the middle can also be of other shapes, as long as the expansion requirements are met. Furthermore, the fiber layer 6 is not a single-layer winding, but rather a continuous layup of multiple layers of fibers.

[0036] Furthermore, a gap is reserved between the key sleeve 5 and the base 1. The gap is used to accommodate the end of the fiber layer 6 and to provide the fiber layer 6 with space to move when it expands and deforms.

[0037] In this embodiment, after the key sleeve 5 of the fixed key 4 is installed, there is a certain space (gap) between it and the base 1. The purpose is to allow the intertwined fibers to have a certain amount of room to move at both ends of the fixed structure, so as to prevent the fibers from being damaged due to the ends getting stuck during the expansion process.

[0038] Furthermore, the inner rubber tube 2 is made of a first elastic material, and the outer rubber tube 3 is made of a second elastic material, wherein the strength of the second elastic material is higher than that of the first elastic material.

[0039] That is, the rubber sleeve is made of a highly elastic material, the inner rubber sleeve 2 is made of a material with lower strength, which is easy to expand; the outer rubber sleeve 3 is made of a material with higher strength to meet the high load requirements of radial compression and axial shear during the setting of the rubber sleeve unit.

[0040] Furthermore, the fiber layer 6 is made of a high-strength composite material; the fiber layer 6 is formed by continuously laying multiple layers of fibers.

[0041] It should be noted that the assembly sequence is usually as follows: 1. Fix the inner rubber tube 2 with rubber material (pay attention to preventing clogging of the holes and vulcanization at both ends); 2. Insert the key 4 into the keyway, with the front and rear keyways surrounding the base 1 in a circle; 3. Start winding the fiber on the front row of fixed keys 4 first, and after completing one pitch, switch to the rear row of fixed keys 4 for winding, and so on, forming an interlaced path; 4. Install the key sleeve 5 and fix it with screws; 5. Lay the outer rubber tube 3 with rubber material and vulcanize it as a whole.

[0042] Furthermore, the base 1 has a hollow tubular structure, and a pressure transmission hole 9 is provided on the side wall of the base 1; the pressure transmission hole 9 connects the inner cavity of the base 1 with the inner surface of the inner rubber cylinder 2, and the pressure transmission hole 9 is located in the area where the inner rubber cylinder 2 is not vulcanized and connected to the base 1.

[0043] The working principle is as follows: First, the working pressure enters the inner rubber cylinder 2 cavity through the pressure transmission hole 9, driving the inner rubber cylinder 2 to expand radially. Subsequently, the high-strength fiber layer 6, pre-wound onto the surface of the inner rubber cylinder 2, begins to expand and deform under the internal pressure. At this stage, the core function of the fiber layer 6 is to limit the excessive expansion of the inner rubber cylinder 2 and to act as the main load-bearing structure, sharing most of the internal pressure. As the pressure continues to rise, the fiber layer 6 further expands outward until its outer surface is in complete contact with the inner wall of the outer rubber cylinder 3. At this point, the outer rubber cylinder 3, supported by the expansion of the fiber layer 6, also begins to expand radially, eventually fitting tightly against the sleeve wall, achieving reliable sealing.

[0044] Furthermore, it also includes a sealing ring 10; the sealing ring 10 is installed at the connection of the packer expansion sleeve unit to prevent pressure leakage when the packer expansion sleeve unit is connected to an adjacent component.

[0045] That is, the sealing ring 10 is installed at the connection of each rubber sleeve unit (or between the connections of each rubber sleeve unit) to prevent pressure leakage of the rubber sleeve unit.

[0046] Furthermore, the base 1 extends axially, and one end of the base 1 is provided with an internal thread interface 11, and the other end is provided with an external thread interface 12. The internal thread interface 11 and the external thread interface 12 are used to realize the series connection between multiple packer expansion tube units.

[0047] In this embodiment, the rubber sleeve unit has a simple structure and is easy to install. Multiple sections of the rubber sleeve unit can be connected and easily disassembled and replaced. This allows the invention to be configured with different quantities to meet different production needs, reduce costs, and effectively solve the problem of existing technologies requiring customized rubber sleeves for different working conditions, leading to a complex product series. Finally, it should be noted that the invention only designs the rubber sleeve unit structure in the oil pipe packer, not the entire oil pipe packer. It still needs to be used in conjunction with pressure transmission equipment, guide shoes, and other devices.

[0048] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

[0049] This background section is provided to generally present the context of the invention. The work of the currently named inventors, the work to the extent described in this background section, and aspects of this section that did not constitute prior art at the time of application are neither expressly nor impliedly acknowledged as prior art to the invention.

Claims

1. A packer swellable element unit, characterized by, The utility model relates to a packer inflation rubber sleeve unit, comprising: a base, an inner rubber sleeve, an outer rubber sleeve, a key, a key sleeve and a fiber layer; the inner rubber sleeve is fixed on the base; the key is arranged on the base; the fiber layer is wound on the key, and the fiber layer is located between the inner rubber sleeve and the outer rubber sleeve; the key sleeve is used for fixing the key; the outer rubber sleeve is fixed on the key sleeve.

2. A packer swellable element as defined in claim 1, wherein, Both ends of the inner rubber sleeve are vulcanized and fixed on the base, and the middle part of the inner rubber sleeve is not vulcanized and connected with the base; the outer rubber sleeve is vulcanized and fixed on the key sleeve.

3. A packer swellable element as defined in claim 1, wherein, A key groove is formed on the outer wall of the base, and the key is inserted into the key groove; the key sleeve is sleeved on the base and fixed on the base by screws to limit the displacement of the key.

4. A packer swellable element as defined in claim 3, wherein, The key groove comprises front and rear rows of key grooves distributed in axial positions; the fiber layer is interlaced and wound between the keys installed in the front row of key grooves and the keys installed in the rear row of key grooves, and the extension path of the fiber layer in the middle part of the inner rubber sleeve is curved.

5. A packer swellable element as defined in claim 3, wherein, A gap is reserved between the key sleeve and the base, which is used to accommodate the end of the fiber layer and provide a moving space for the fiber layer when it expands and deforms.

6. A packer swellable element as defined in claim 1, wherein, The inner rubber sleeve is made of a first elastic material, and the outer rubber sleeve is made of a second elastic material, wherein the strength of the second elastic material is higher than that of the first elastic material.

7. A packer swellable element as defined in claim 1, wherein, The fiber layer is made of a high-strength composite material; the fiber layer is continuously laid by multiple layers of fibers.

8. The packer swellable element of claim 2, wherein, The base has a hollow tubular structure, and a pressure transmission hole is formed in the side wall of the base; the pressure transmission hole communicates the inner cavity of the base with the inner surface of the inner rubber sleeve, and is located in the region of the inner rubber sleeve that is not vulcanized and connected with the base.

9. The packer swellable element of claim 1, wherein, It also includes a sealing ring; the sealing ring is installed at the connection of the packer inflation rubber sleeve unit, and is used to prevent pressure leakage when the packer inflation rubber sleeve unit is connected with adjacent components.

10. The packer swellable element of claim 1, wherein, The base extends in the axial direction, and one end of the base is provided with an inner threaded interface, and the other end is provided with an outer threaded interface; the inner threaded interface and the outer threaded interface are used to realize the series connection between multiple packer inflation rubber sleeve units.

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