An all-contact type inflatable rubber seal sleeve structure based on an optimization algorithm

Abstract

The application discloses a full-contact expandable rubber sealing sleeve structure based on an optimization algorithm and belongs to the technical field of oilfield drilling engineering. The structure comprises an expansion cone, an expansion pipe, an outer sleeve and a sealing rubber sleeve. The conventional rubber sleeve is in a trapezoidal structure, and the optimized rubber sleeve is in a circular arc structure. The full-contact expandable rubber sealing sleeve structure is obtained based on a numerical optimization algorithm. The algorithm comprises the following steps: a parameterized numerical model of the expansion pipe sealing sleeve is established, a circular arc radius is taken as a variable parameter R, an optimization target is an area under a contact pressure curve of the rubber sleeve and an upper space along a length direction of the rubber sleeve after expansion, and a constraint condition is that a length L of the rubber sleeve and a central wall thickness t are invariable. The technical scheme is verified by experiments, and an actual sealing pressure is increased by more than 70%, so that the application of the expandable packer in a shale gas fracturing environment is met.

Description

Technical Field

[0001] This invention relates to the field of oilfield drilling engineering technology, and in particular to a full-contact expandable rubber sealing sleeve structure based on an optimization algorithm. Background Technology

[0002] In technologies such as expandable packers, expandable tube tailpipe hangers, expandable tube casing padding, and expandable tube open-hole sealing, the expanded tube needs to overlap with the upper casing and open-hole formation after expansion. The overlapping mechanism mainly achieves suspension and sealing by the tight fit between the expanded tube's vulcanized rubber sleeve and the upper channel. Therefore, the structure of the expandable rubber sealing sleeve directly affects the suspension and sealing effect. With the development of shale gas technology, expandable packers are increasingly used in staged fracturing of horizontal sections of shale gas formations, placing higher demands on sealing pressure and necessitating improvements to the sealing sleeve structure to increase its packing pressure after expansion. Simultaneously, with the development of expandable tube technology, the operating length of the expandable tube is gradually increasing, requiring the sealing sleeve to provide greater suspension force.

[0003] Traditional expandable rubber seal design relies mainly on empirical formulas, engineering experience, and extensive indoor experimental verification. This design approach results in a relatively simple expandable rubber sleeve structure, high verification costs, and low sealing pressure. Summary of the Invention

[0004] The purpose of this invention is to provide a full-contact expandable rubber sealing sleeve structure based on an optimization algorithm. This addresses the problems of high verification costs, long cycles, and insufficient sealing pressure caused by the traditional expandable rubber sealing sleeve structure design relying mainly on empirical formulas, engineering experience, and extensive indoor experimental verification. This invention achieves full contact between the rubber sleeve and the upper channel after expansion, greatly increasing the effective contact area and significantly improving the sealing pressure between the expanded rubber sleeve and the upper channel without increasing the compression of the rubber sleeve.

[0005] The embodiments of the present invention are implemented as follows:

[0006] A fully contactable expandable rubber sealing sleeve structure based on an optimization algorithm is characterized by comprising an expansion cone, an expansion tube, an outer casing, a trapezoidal rubber sleeve, and an arc-shaped rubber sleeve. The expansion cone is placed inside the expansion tube, and the expansion tubes are connected by threads to form a tube string. The rubber sleeves are evenly distributed on the outer wall of the expansion tube. Drill pipe or tubing is connected to the expansion cone to form an inner tubing string. The expansion tube string is lowered into the well through the inner tubing string, and the expansion tube is expanded by high-pressure fluid, thereby achieving the purpose of drilling and completion operations.

[0007] The trapezoidal rubber sleeve is a conventional structure, while the arc rubber sleeve is an optimized structure. The arc structure of the fully contact expandable rubber sealing sleeve is obtained based on a numerical optimization algorithm. The algorithm includes the following steps: establishing a parameterized numerical model of the expansion tube sealing rubber sleeve, with the arc radius as a variable parameter R, the optimization objective being the area under the contact pressure curve between the expanded rubber sleeve and the upper space along the rubber length direction, and the constraint condition being that the rubber sleeve length L and the central wall thickness t remain unchanged.

[0008] In a preferred embodiment of the present invention, the arc-shaped rubber sleeve is vulcanized and bonded together with the expansion tube, and vulcanized on the outer wall of the last one or several expansion tubes.

[0009] In the above scheme, the outer wall of the expandable arc-shaped rubber sleeve adopts an arc-shaped structure. The center of the arc in the arc-shaped structure is located on the extension line of the length center, and the radius R / L ranges from 3 to 5. Here, R is the radius of the arc, and L is the length of the vulcanized area of ​​the rubber sleeve.

[0010] Taking the area A formed along the length of the rubber sleeve by the contact pressure between the expanded rubber sleeve and the casing as the design variable, it can be expressed as:

[0011] A = [L, t, R]

[0012] t is the thickness of the trapezoidal rubber sleeve, which is also equal to the thickness of the thinnest part of the circular arc rubber sleeve.

[0013] The length L and thickness t of the rubber sleeve are designed to meet the following ranges based on suspension and sealing requirements:

[0014] a≤L≤b

[0015] c≤L≤d

[0016] The objective function is Maximum Contact(A), which is formed by the contact pressure between the rubber sleeve and the upper channel after expansion along the displacement direction. The optimal sealing pressure is obtained by adjusting the radius R of the arc.

[0017] The beneficial effects of the embodiments of the present invention are:

[0018] This invention provides a fully contact expandable rubber sealing sleeve structure based on an optimization algorithm. Without changing the variable compression of the rubber sleeve, the contact pressure between the rubber sleeve and the upper channel after expansion presents a fully contact mode. Experiments have verified that the actual sealing pressure is increased by more than 70%, which meets the application requirements of expandable packers in shale gas fracturing environments. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the optimization algorithm flow for the fully contactable expandable rubber sealing sleeve structure based on the optimization algorithm of the present invention.

[0021] Figure 2 This is a schematic diagram of the structure of the fully contact expandable rubber sealing sleeve based on the optimization algorithm of the present invention;

[0022] Figure 3 for Figure 2 A magnified view of a portion of the image;

[0023] Figure 4 This is the contact pressure curve between the expandable rubber sleeve and the upper space after expansion.

[0024] In the diagram: 1-Expansion cone; 2-Expansion tube; 3-Outer sleeve; 4-Trapezoidal rubber sleeve; 5-Circular arc rubber sleeve. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] Please refer to Figure 1 The first embodiment of the present invention provides a full-contact expandable rubber sealing sleeve structure based on an optimization algorithm. The structure is obtained based on a numerical optimization algorithm, which includes the following steps: establishing a parameterized numerical model of the expansion tube sealing sleeve, with the arc radius as a variable parameter R, the optimization objective being the area under the contact pressure curve between the expanded rubber sleeve and the upper space along the rubber length direction, and the constraint condition being that the rubber sleeve length L and the central wall thickness t remain unchanged.

[0027] A parametric numerical model of the expansion sealing cylinder was established using batch commands and Python statements. On the ISIGHT optimization platform, file parsing was used to automatically modify the input and output files of the parametric model. The numerical calculation results were then retrieved via a procedure set, enabling automatic model modification, calculation submission, and result extraction. SolidWorks components were used to perform parametric analysis on the geometric model of the sealing cylinder, modifying relevant design variables. Batch commands were then used with Python statements to complete the finite element model establishment and numerical calculation solution until the optimal design effect was achieved.

[0028] like Figures 2-3 As shown, a fully contactable expandable rubber sealing sleeve structure based on an optimization algorithm includes an expansion cone 1, an expansion tube 2, an outer casing 3, a trapezoidal rubber sleeve 4, and a circular arc rubber sleeve 5. The expansion cone is placed inside the expansion tube, and the expansion tubes are connected by threads to form a tube string. The rubber sleeves are vulcanized at equal intervals on the outer wall of the last one or several expansion tubes. The drill pipe or tubing is connected to the expansion cone to form an inner tubing string. The expansion tube string is lowered into the well through the inner tubing string, and the expansion tube is expanded by high-pressure fluid, thereby achieving the purpose of drilling and completion operations. The trapezoidal rubber sleeve 4 is a conventional rubber structure, and the circular arc rubber sleeve 5 is an optimized structure. The fully contactable expandable circular arc rubber sealing sleeve structure is obtained based on a numerical optimization algorithm. The algorithm includes the following steps: establishing a parameterized numerical model of the expansion tube sealing sleeve, with the arc radius as a variable parameter R; the optimization objective is the area under the contact pressure curve between the expanded rubber sleeve and the upper space along the rubber length direction; and the constraints are that the rubber sleeve length L and the central wall thickness t remain unchanged.

[0029] In a preferred embodiment of the present invention, the arc-shaped rubber sleeve 5 is vulcanized and bonded to the expansion tube 2, and the arc-shaped rubber sleeves are evenly distributed on the outer wall of the expansion tube 2.

[0030] In the above scheme, the outer wall of the arc-shaped rubber sleeve adopts an arc-shaped structure.

[0031] Furthermore, in the arc-shaped structure, the center of the arc is located on the extension line of the length center, and the radius R / L ranges from 3 to 5. Here, R is the radius of the arc, and L is the length of the vulcanized region of the rubber sleeve.

[0032] Figure 4 This is a schematic diagram of the pressure curve between the expandable sealing sleeve and the sleeve after expansion. For the same sleeve size and the same compression, the pressure curves of the conventional sealing sleeve structure and the arc-shaped sealing sleeve structure after expansion are compared.

[0033] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A full-contact expandable rubber sealing sleeve structure based on an optimization algorithm, characterized in that, It includes an expansion cone (1), an expansion tube (2), an outer casing (3), a trapezoidal rubber sleeve (4), and an arc rubber sleeve (5). The expansion cone (1) is placed inside the expansion tube (2). The expansion tubes (2) are connected by threads to form an expansion tube string. The rubber sleeves are evenly distributed on the outer wall of the expansion tube (2). The drill pipe or tubing is connected to the expansion cone (1) to form an inner tubing string. The expansion tube string is lowered into the well through the inner tubing string. The expansion tube is expanded by high-pressure liquid, thereby achieving the purpose of drilling and well completion operations. Among them, the trapezoidal rubber sleeve (4) is a conventional structure, and the optimized structure of the arc rubber sleeve (5) is obtained based on a numerical optimization algorithm. The algorithm includes the following steps: establishing a parameterized numerical model of the full-contact expandable rubber sealing sleeve structure, with the arc radius as a variable parameter R, and the optimization objective being the area under the contact pressure curve between the expanded arc rubber sleeve (5) and the outer sleeve (3) along the length direction of the arc rubber sleeve (5). The constraint condition is that the length L of the arc rubber sleeve and the central wall thickness t remain unchanged. The outer wall of the arc rubber sleeve (5) adopts an arc structure; the center of the arc in the arc structure is located on the extension line of the length center, and the radius R / L ranges from 3 to 5, where R is the radius of the arc and L is the length of the vulcanized area of ​​the rubber sleeve. The area A formed by the contact pressure between the expanded arc rubber sleeve (5) and the outer sleeve (3) along the length of the arc rubber sleeve (5) is taken as the design variable and can be expressed as: A=[L,t,R]; the central wall thickness t is the thickness of the trapezoidal rubber sleeve, which is also equal to the thickness of the thinnest part of the arc rubber sleeve; The area formed by the contact pressure between the expanded arc rubber sleeve (5) and the outer sleeve (3) along the length of the arc rubber sleeve (5) is taken as the objective function, and the optimal sealing pressure is obtained by adjusting the arc radius R.

2. The full-contact expandable rubber sealing sleeve structure based on optimization algorithm according to claim 1, characterized in that, The circular arc rubber sleeve (5) is vulcanized at equal intervals on the outer wall of the last one or several expansion tubes (2).

3. The full-contact expandable rubber sealing sleeve structure based on optimization algorithm according to claim 1, characterized in that, The arc-shaped rubber sleeve (5) is an expandable arc-shaped rubber sleeve.

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