A polyhedral edge-type gradual sealing temporary plugging ball

Abstract

The application discloses a polyhedral edge gap type gradual sealing temporary plugging ball and belongs to the technical field of oil and gas exploitation. The outer surface of the temporary plugging ball is composed of multiple polygonal surfaces, and adjacent polygonal surfaces intersect to form edges, the edges are provided with a rounded corner structure, and the outer surface of the temporary plugging ball is made of a flexible material. When the temporary plugging ball is set at a perforation hole, the edges can be in contact with the edge of the perforation hole to form an initial sealing gap, then the flexible material is deformed under the action of pressure difference to gradually close the initial sealing gap and realize complete plugging. The application can not only solve the technical bottleneck of low reliability of the traditional temporary plugging ball in setting the perforation hole, but also can enhance the mechanical engagement capacity with irregular perforation holes through the optimized polyhedral geometric structure, thereby significantly improving the success rate of hydraulic fracturing operation and economic benefits.

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction technology, and in particular to a polyhedral prismatic progressive sealing temporary plugging ball. Background Technology

[0002] In the field of oil and gas extraction, hydraulic fracturing technology is a core means of developing unconventional oil and gas resources. Its basic principle is to form a network of fractures in the formation by pumping fracturing fluid under high pressure, thereby widening the flow channels for oil and gas. Among them, the temporary plugging ball technology plays a key role in the multi-stage cluster fracturing process. Through the mechanical cooperation of the ball with the dominant fluid ingress perforation, temporary plugging is achieved, forcing the subsequent fracturing fluid to be diverted to other perforation clusters or fractures that have not successfully initiated or have not fully expanded, thereby realizing the flow distribution between fractures and the directional modification of fracturing fluid.

[0003] In practical applications, the success rate of temporary plugging ball sealing is often low, and the core problem lies in the complex fluid dynamics phenomenon—the water hammer effect of plugging holes. The physical mechanism is as follows: When the high-speed fracturing fluid carrying the temporary plugging ball arrives at the perforation orifice, the conventional smooth ball will instantly and completely seal the orifice inlet. At this time, the high-speed fluid inside the orifice continues to flow into the depth of the fracture due to inertia, and the blockage of the inlet prevents subsequent fluid from being replenished, thus forming a near-vacuum cavity behind the contact surface between the temporary plugging ball and the fracture. This cavity is extremely unstable, and the surrounding high-pressure fluid and possible fracture backflow fluid will rapidly backfill it, causing the cavitation to collapse and generating a strong pressure pulse pointing towards the wellbore. The thrust generated by this pulse often exceeds the resultant force of the weight and static pressure of the temporary plugging ball, pushing it back to the wellbore from the sealing position. The pushed-back temporary plugging ball will move back towards the orifice under the action of the wellbore fluid to attempt to set. If the structure is not improved, the above-mentioned cycle of "setting-ejection-resetting-resetting-ejection" will continue for several minutes to tens of minutes at a frequency of 1-10Hz, causing the temporary plugging ball to always be in a dynamic and unstable state, unable to form a durable and reliable seal, which seriously affects the efficiency of temporary plugging fracturing operations.

[0004] In existing technologies, researchers have proposed a variety of optimization solutions: In terms of material improvement, increasing the density of the spheres (such as steel spheres or ceramic spheres) can enhance gravity, or using biodegradable materials can solve the problem of unclogging in the later stages. However, such solutions are mainly aimed at static sealing and post-treatment, and have limited improvement on the water hammer effect in dynamic setting. In terms of structural strength enhancement, optimizing the internal structure through hollow design, composite materials, etc. can improve the impact resistance, but it still cannot avoid the pressure impact problem caused by instantaneous complete sealing.

[0005] Existing solutions are mostly based on static sealing, which fails to fundamentally solve the problem of fluid dynamic instability caused by instantaneous complete sealing. Therefore, there is an urgent need for an innovative design for the dynamic setting process to control the fluid characteristics during the sealing stage and eliminate the water hammer effect. Summary of the Invention

[0006] To address the aforementioned problems, this invention aims to provide a polyhedral prism-type progressive sealing temporary plugging ball.

[0007] The technical solution of the present invention is as follows:

[0008] A polyhedral prismatic progressive sealing temporary plugging ball is disclosed. The outer surface of the temporary plugging ball is composed of multiple polygonal faces, and adjacent polygonal faces intersect to form edges. The edges are provided with rounded corners. The outer surface of the temporary plugging ball is made of a flexible material. When the temporary plugging ball is set at the perforation orifice, it can form an initial sealing gap by contacting the edge of the perforation orifice through the edges. Then, the deformation capacity of the flexible material under the action of pressure difference causes the initial sealing gap to gradually close, achieving complete sealing.

[0009] Preferably, the polygonal surface is any one or more of regular polygons, irregular polygons, and curved polygons, and when the polygonal surface is a curved polygon, its overall structure is non-circular.

[0010] Preferably, the regular polygon is any one or more of the following: equilateral triangle, square, regular pentagon, regular hexagon, and regular octagon.

[0011] Preferably, the irregular polygon is any one or more of the following: scalene triangle, rectangle, trapezoid, irregular quadrilateral, and irregular pentagon.

[0012] Preferably, the polygonal surfaces are assembled using any of the following methods:

[0013] (a) Uniform distribution of a single shape: It is composed of the same type of polygons arranged in a regular geometric pattern, with the difference in side length between adjacent polygons not exceeding 20%, to ensure structural symmetry and uniform stress distribution.

[0014] (b) Multiple shape combination distribution: Two or more different shapes of polygons are interlaced and spliced ​​according to a predetermined rule, with each shape of polygon accounting for 10% to 90% of the total number of polygons, forming a heterogeneous surface structure;

[0015] (c) Differentiated distribution by region: The surface of the sphere is divided into 2 to 6 regions according to spherical coordinates. Different regions are spliced ​​with polygons of different shapes or sizes. The boundaries of the regions are smoothly connected by transition polygons to avoid abrupt stress changes.

[0016] Preferably, the temporary plugging ball is a hollow temporary plugging ball or a solid temporary plugging ball. The hollow temporary plugging ball is composed of a flexible polyhedral spherical shell, and the solid temporary plugging ball is composed of a spherical core and a flexible polyhedral spherical shell.

[0017] Preferably, the thickness H and the edge length L of both the first and second flexible polyhedral spherical shells are greater than or equal to 0.05D and less than or equal to 0.5D, where D is the diameter of the circumscribed sphere of the first and second flexible polyhedral spherical shells.

[0018] Preferably, the diameter D of the circumscribed ball is greater than or equal to 5 mm and less than or equal to 50 mm.

[0019] Preferably, the core ball is made of a biodegradable material or a non-biodegradable elastic material; the biodegradable material is any one or more of polylactic acid, polyglycolic acid, polycaprolactone, polyhydroxyalkanoate, and polyvinyl alcohol; the non-biodegradable elastic material is a thermoplastic elastomer or a thermosetting elastomer.

[0020] Preferably, the elastic modulus of the flexible material is greater than or equal to 0.01 GPa and less than or equal to 10 GPa, and the Poisson's ratio of the flexible material is greater than or equal to 0.2 and less than or equal to 0.49.

[0021] The beneficial effects of this invention are:

[0022] This invention not only solves the technical bottleneck of low reliability of traditional temporary plugging ball-setting orifices, but also enhances the mechanical engagement with irregular orifices through optimized polyhedral geometry, significantly improving the success rate and economic benefits of hydraulic fracturing operations. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A schematic diagram of a polyhedral prism-type progressive sealing temporary plugging ball structure with a surface composed of equilateral triangles;

[0025] Figure 2 A schematic diagram of a polyhedral prism-type progressive sealing temporary plugging ball structure whose surface is composed of regular pentagons;

[0026] Figure 3 This is a schematic diagram of a polyhedral prismatic progressive sealing temporary plugging ball structure whose surface is composed of regular hexagons and regular pentagons;

[0027] Figure 4 A schematic diagram of a polyhedral prism-type progressive sealing temporary plugging ball structure whose surface is composed of irregular polygons;

[0028] Figure 5A schematic diagram of a solid, multi-faceted, prismatic, progressive sealing, temporary plugging ball with a planed surface.

[0029] Figure 6 A schematic diagram of a polyhedral prism-type progressive sealing temporary plug ball seated orifice with a surface composed of regular hexagons and regular pentagons;

[0030] Figure 7 This is a schematic diagram of the cross-section of the polyhedral prismatic progressive sealing temporary plug ball seated orifice, whose surface is composed of regular hexagons and regular pentagons.

[0031] Figure 8 A schematic diagram of the experimental process for setting a common temporary plug ball to seal the orifice;

[0032] Figure 9 This is a schematic diagram of the experimental process of a polyhedral prism-type progressive sealing temporary plug ball settling the orifice, whose surface is composed of regular hexagons and regular pentagons. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and technical features described in this application can be combined with each other. It should also be pointed out that, unless otherwise indicated, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terms "comprising" or "including" and similar words used in this invention refer to elements or objects preceding the word that encompass the elements or objects listed following the word and their equivalents, without excluding other elements or objects.

[0034] like Figure 1-9 As shown, the present invention provides a polyhedral prismatic progressive sealing temporary plugging ball. The outer surface of the temporary plugging ball is composed of multiple polygonal faces, and adjacent polygonal faces intersect to form edges. The outer surface of the temporary plugging ball is made of a flexible material. When the temporary plugging ball is set at the perforation orifice, it can form an initial sealing gap by contacting the edge of the perforation orifice through the edges. Then, the initial sealing gap is gradually closed by the deformation capacity of the flexible material under the action of pressure difference, so as to achieve complete sealing.

[0035] In this invention, by setting the temporary plugging ball as a non-spherical polyhedral structure, the unique polyhedral edge structure allows the ball to contact the orifice edge through its edges regardless of the angle or method of setting, forming a controlled ridge channel (i.e., the initial sealing gap) at the contact point. During the initial setting stage, this ridge channel maintains communication between the fluid inside the fracture and the outside, effectively preventing cavity formation and subsequent water hammer effects caused by instantaneous complete sealing. As the pressure difference between the inside and outside of the casing increases, the temporary plugging ball, made of flexible material on its outer surface, undergoes controlled deformation (elastic or elastoplastic response) under the pressure difference, and the ridge channel gradually contracts until it is completely closed, achieving a gradual transition from a micro-guiding state to a completely sealed state. In summary, this invention not only solves the technical bottleneck of low reliability in traditional temporary plugging ball setting orifices but also enhances the mechanical engagement capability with irregular orifices through optimized polyhedral geometry, significantly improving the success rate and economic benefits of hydraulic fracturing operations.

[0036] When using this invention, the temporary plugging ball has progressive sealing characteristics, and its working process includes the following stages:

[0037] (a) Initial setting stage: After the temporary plugging ball reaches the perforation orifice, its edge contacts the edge of the orifice, forming an initial sealing gap, allowing fluid to pass through at a controlled flow rate;

[0038] (b) Pressure differential establishment stage: As the pressure inside the casing increases, the pressure differential gradually increases, and the temporary plugging ball shell made of flexible material begins to deform under the action of pressure differential;

[0039] (c) Gradual sealing stage: When the pressure difference reaches the threshold, a temporary plugging ball made of flexible material is used to deform the shell so that the initial sealing gap gradually shrinks until it is completely closed, thus achieving complete sealing.

[0040] In the above process, the initial sealing gap formed by the edge can avoid instantaneous complete blockage during initial setting and eliminate the water hammer effect; the flexible shell structure with controllable deformation capability can undergo controlled deformation under pressure difference to achieve a smooth transition from liquid permeation to sealing.

[0041] In one specific embodiment, the initial sealing gap is greater than or equal to 0.1 mm and less than or equal to 5 mm.

[0042] In one specific embodiment, the polygonal surface is any one or more of regular polygons, irregular polygons, and curved polygons, and when the polygonal surface is a curved polygon, its overall structure is non-circular.

[0043] Optionally, the regular polygon is any one or more of an equilateral triangle, square, regular pentagon, regular hexagon, and regular octagon. It should be noted that the regular polygons in this embodiment are only a preferred subset of regular polygons of the present invention; other regular polygons in the prior art can also be applied to the present invention.

[0044] Optionally, the irregular polygon can be any one or more of a scalene triangle, rectangle, trapezoid, irregular quadrilateral, and irregular pentagon. It should be noted that the irregular polygons in this embodiment are only a preferred subset of irregular polygons of the present invention, and other irregular polygons in the prior art can also be applied to the present invention.

[0045] In the above embodiments, the invention can be adapted to perforations of different shapes and sizes through diverse surface structure designs.

[0046] In one specific embodiment, the polygonal faces are assembled using any of the following methods:

[0047] (a) Uniform distribution of a single shape: It is composed of the same type of polygons arranged in a regular geometric pattern, with the difference in side length between adjacent polygons not exceeding 20%, to ensure structural symmetry and uniform stress distribution.

[0048] like Figure 1 As shown, a polyhedral, prismatic, progressive sealing stub sphere has an outer surface composed of a shape (equilateral triangle). Figure 2 As shown, a polyhedral prism-type progressive sealing temporary plug sphere has an outer surface composed of a shape (regular pentagon). It should be noted that, in addition to equilateral triangles and regular pentagons, the surface shape can also be a regular polygon such as a rectangle or regular hexagon, or an irregular planar figure (plane or curved surface).

[0049] (b) Multiple shape combination distribution: Two or more different shapes of polygons are interlaced and spliced ​​according to a predetermined rule, with each shape of polygon accounting for 10% to 90% of the total number of polygons, forming a heterogeneous surface structure;

[0050] like Figure 3 As shown, a polyhedral, prismatic, progressive sealing sphere has an outer surface composed of two different shapes (regular hexagons and regular pentagons) joined together. Figure 4 As shown, a polyhedral prismatic progressive sealing temporary plug sphere has an outer surface composed of two different shapes (irregular pentagons and irregular hexagons). It should be noted that the outer surface can also be composed of two or more other different shapes (including a mixture of planar and curved surfaces).

[0051] (c) Differentiated distribution by region: The surface of the sphere is divided into 2 to 6 regions according to spherical coordinates. Different regions are spliced ​​with polygons of different shapes or sizes. The boundaries of the regions are smoothly connected by transition polygons to avoid abrupt stress changes.

[0052] In the above embodiments, all splicing methods can ensure that when the temporary plugging ball contacts the perforation hole in any posture, at least one set of edges and the edge of the hole form an effective gap channel, avoiding the failure of the initial gap due to posture deviation and ensuring the reliability of the progressive seal.

[0053] In one specific embodiment, the temporary plugging ball is a hollow temporary plugging ball or a solid temporary plugging ball, wherein the hollow temporary plugging ball is composed of a flexible polyhedral spherical shell, such as... Figure 5 As shown, the solid temporary blocking ball consists of a ball core and a flexible polyhedral spherical shell.

[0054] In one specific embodiment, the thickness H and the edge length L of both the first and second flexible polyhedral spherical shells are greater than or equal to 0.05D and less than or equal to 0.5D, where D is the circumscribed sphere diameter of the first and second flexible polyhedral spherical shells. Optionally, the circumscribed sphere diameter D is greater than or equal to 5mm and less than or equal to 50mm.

[0055] In a specific embodiment, when the temporary clogging ball is a solid temporary clogging ball, the structural form of the temporary clogging ball includes the following two types:

[0056] (a) The entire temporary plugging ball is made of the same material and is integrally molded. The core and the flexible polyhedral shell are continuous integral structures.

[0057] (b) Composite multi-layer material combination structure, the core of the temporary blocking ball is made of supporting material, and the outer layer of the core is covered by a flexible polyhedral spherical shell made of flexible material.

[0058] In the above embodiments, by providing two structural forms, namely an integral single material and a composite multi-layer material, and by combining the specific selection of materials, the present invention can meet the working condition adaptability of different well depths, fracturing pressures, and post-unblocking needs, while taking into account structural strength and deformation controllability.

[0059] When the structure is a monolithic, single-material structure, the polyhedral body of the temporary plugging ball is a one-piece molded design without layers. Its outer surface is directly formed by splicing polygonal faces to create edges, providing geometric shape, mechanical support, and deformation capabilities. When it is a composite, multi-layered material combination structure, it includes a core matrix and an outer polygonal face structure. The core matrix provides basic mechanical support, while the intersecting polygonal faces of the outer layer form edges, serving as a functional micro-flow guiding structure for fluid control. The design of this invention is based on the following principle: During initial setting, the edges contact the orifice edge to form an initial sealing gap. These gaps allow the fluid within the fracture to remain connected to the outside, preventing the formation of cavities in the plugging area. As the wellbore pressure increases, the polygonal faces undergo controlled deformation under the pressure differential, gradually shrinking the initial sealing gap until it is completely closed, achieving a final reliable seal.

[0060] In one specific embodiment, the temporary blocking ball is made of a biodegradable or non-biodegradable elastic material; the biodegradable material is any one or more of polylactic acid, polyglycolic acid, polycaprolactone, polyhydroxyalkanoates, and polyvinyl alcohol; the non-biodegradable elastic material is a thermoplastic elastomer or a thermosetting elastomer. Optionally, the thermoplastic elastomer is any one or more of thermoplastic polyolefin elastomers, dynamically vulcanized thermoplastic elastomers, and polyurethane rubber, and the thermosetting elastomer is silicone rubber and / or fluororubber.

[0061] In one specific embodiment, the elastic modulus of the flexible material is greater than or equal to 0.01 GPa and less than or equal to 10 GPa, and the Poisson's ratio of the flexible material is greater than or equal to 0.2 and less than or equal to 0.49. Optionally, the flexible material is the non-degradable elastic material described in the above embodiments.

[0062] In one specific embodiment, the edge is provided with a rounded corner structure, and the radius R of the rounded corner satisfies: 0.1mm ≤ R ≤ 5mm. In this embodiment, the rounded corner structure can reduce the stress concentration coefficient when the edge contacts the edge of the hole, thereby reducing local stress peaks; on the other hand, it can reduce material wear and damage during the contact process, improving structural durability and sealing safety.

[0063] In summary, compared with existing temporary plugging ball technologies, the temporary plugging ball of this invention has a simple structure, is easy to manufacture, can eliminate water hammer effect, and has a good setting rate, thus possessing the following advantages:

[0064] (1) The temporary plugging ball of the present invention has excellent structural interchangeability. The structural form (integral single material or composite multi-layer material combination) can be flexibly selected according to the actual working conditions. The shape (planar or curved), quantity, and material (degradable or non-degradable) of the polygonal surface of the ball can be adjusted as needed to adapt to the performance requirements of different fracturing scenarios.

[0065] (2) The outer surface of the temporary plugging ball of the present invention adopts a polygonal splicing structure. During setting, the contact with the orifice is a multi-point / line contact between the edge and the edge of the orifice. Compared with the surface contact of the traditional smooth circular surface, it can enhance the mechanical interlocking effect with the orifice, effectively resist fluid impact, reduce the risk of being washed away, and significantly improve reliability. Furthermore, by setting a rounded corner structure on the edge, the stress concentration coefficient during contact can be reduced, and the wear of the material during repeated setting can be reduced, taking into account both impact resistance and structural durability, and extending service life.

[0066] (3) The stable setting of the temporary plugging ball of the present invention: Due to the edge structure formed by the polygonal surface, regardless of the angle at which it contacts the orifice, an initial gap is formed between the edge and the edge of the orifice. This gap can maintain the connectivity between the fluid in the fracture and the external wellbore, avoid the formation of a cavity due to instantaneous complete blockage, achieve a smooth transition and gradual establishment of pressure, alleviate the water hammer effect of the plugging orifice, and improve the success rate and sealing reliability of the temporary plugging ball under complex well conditions. The setting process follows three stages: initial setting → pressure differential establishment → gradual plugging. When the pressure differential reaches the threshold, the edge channel gradually contracts and closes.

[0067] (4) The surface of the temporary plug ball of the present invention adopts a diversified polygon splicing design. Its irregular shape can be adapted to perforations of different shapes (regular or irregular) and sizes. Even if the perforation has deformation or irregular defects, it can still achieve effective sealing through flexible fitting of the edge and the edge of the perforation. It is applicable to a wider range of scenarios.

[0068] (5) Balance between structural strength and flow efficiency: This invention can achieve precise control of “edge density” by adjusting the total number of polygonal faces. The specific total number of polygonal faces can be adjusted according to the diameter D of the circumscribed sphere to ensure that the optimal balance is achieved between the initial flow efficiency and the long-term structural strength, thus avoiding the performance shortcomings of a single structural design.

[0069] In a specific embodiment, taking a polyhedral, prismatic, progressive sealing temporary plugging ball composed of regular hexagons and regular pentagons as an example, the key process of its setting and sealing on the perforation orifice of the casing is as follows: Figure 6 and Figure 7 As shown. In this embodiment, the outer sphere diameter of the polyhedral prismatic progressive sealing temporary plugging ball is D=20mm (fitting orifice diameter 16mm); the polygon shape is a combination of regular pentagon and regular hexagon; the side length L=2.5mm, the outer layer thickness H=0.75mm; the initial gap d=0.6mm; the outer layer material is: dynamically vulcanized thermoplastic elastomer (TPV), E=0.5GPa, Poisson's ratio v=0.45.

[0070] When the temporary plugging ball reaches the orifice, its unique polyhedral edges first contact the orifice edge (as shown by the arrow in the figure), forming a tiny initial gap. These gaps allow the fluid within the fracture space to remain connected to the external wellbore during the initial setting phase, effectively preventing the formation of cavities within the fracture due to instantaneous complete sealing, thus eliminating the water hammer effect—vacuum backflow of fluid impacting the plugging ball. As the fracturing fluid pressure inside the casing increases, the polyhedral shell material of the plugging ball undergoes controlled deformation, with the polygonal faces conforming to the orifice contour, and the initial gap gradually shrinks. Finally, under high pressure, the material fully deforms, completely covering the orifice to form a reliable seal.

[0071] In another specific embodiment, to further verify the advantages of the temporary plugging ball of the present invention, a setting test was conducted under the same working conditions (orifice diameter 15mm, fracturing fluid flow rate 7.44m³ / min, and plugging ball diameter 20mm) using a conventional smooth temporary plugging ball and the polyhedral prismatic progressive sealing temporary plugging ball described in the present invention. The comparison results are as follows:

[0072] like Figure 8 As shown in the diagram, the setting experiment of a conventional smooth temporary plugging ball illustrates its dynamic state during setting: at the instant of initial contact between the plugging ball and the orifice (approximately 0.961 s), the orifice inlet is instantly and completely blocked due to the lack of a flow-guiding structure on the ball's surface. At this moment, the high-speed fracturing fluid flowing inside the orifice continues to propel into the depth of the fracture due to inertia, and the blockage of the inlet prevents fluid replenishment, rapidly forming a local cavity with a diameter of approximately 64.6 mm on the outer side of the area where the plugging ball and the orifice wall are in contact (observed at T=1.009 s). This cavity rapidly collapses at T=1.077 s, and the surrounding high-pressure fluid and fracture return fluid rush back at high speed, generating a water hammer impact force far exceeding the combined force of the plugging ball's own weight and static pressure, directly pushing the plugging ball back into the wellbore from the orifice position (T=1.183 s).

[0073] like Figure 9 As shown, during the setting process of the polyhedral prism-type progressive sealing plug ball composed of regular hexagons and regular pentagons of the present invention, due to its unique edge structure, the fracturing fluid can flow through the channel gap formed between the plug ball and the orifice at the moment of setting (T=2.66S), avoiding the generation of local cavities, making its setting stable, and achieving complete sealing as the pressure inside the sleeve increases thereafter.

[0074] The comparison of the results shows that the multi-faceted prismatic progressive sealing temporary plugging ball of the present invention can avoid the complete sealing of the orifice at the moment of setting through the surface edge design, eliminate the water hammer effect from the source, and achieve a smooth transition of "initial micro-flow-progressive sealing-stable pressure bearing". The setting stability, operation success rate and the improvement effect on fracturing effect are significantly better than conventional products.

[0075] The above description is merely a representative embodiment of the present invention and is not intended to limit the present invention in any way. Any embodiment made by those skilled in the art without departing from the scope of the present invention and utilizing the disclosed technical content is an equivalent embodiment of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A polyhedral reentrant progressively sealing temporary plugging ball, characterized in that, An outer surface of the temporary plugging ball is composed of a plurality of polygonal faces, and adjacent polygonal faces intersect to form edges, the edges are provided with a rounded corner structure, and the outer surface of the temporary plugging ball is made of a flexible material; when the temporary plugging ball is set at a perforation hole, an initial sealing gap can be formed by the edges in contact with the edge of the perforation hole, then the initial sealing gap is gradually closed to achieve complete plugging under the action of differential pressure through the deformation ability of the flexible material; in the initial setting stage, the initial sealing gap can keep the fluid in the fracture in communication with the outside, effectively preventing the formation of cavities and subsequent water hammer effect caused by instantaneous complete plugging.

2. The polyhedral faceted slotted progressive seal and bridge plug ball of claim 1, wherein, The shape of the polygonal face is any one or more of regular polygon, irregular polygon, curved polygon, and when the shape of the polygonal face is a curved polygon, the whole is a non-circular structure.

3. The polyhedral faceted, slotted, progressively sealing, ball-type bridge plug of claim 2, wherein, The regular polygon is any one or more of equilateral triangle, square, regular pentagon, regular hexagon, and regular octagon.

4. The polyhedral slotted progressive seal and bridge plug ball of claim 2, wherein, The irregular polygon is any one or more of scalene triangle, rectangle, trapezoid, irregular quadrilateral, and irregular pentagon.

5. The polyhedral faceted slotted progressive seal and bridge plug ball of claim 2, wherein, The polygonal face is formed by any one of the following ways: (a) uniform distribution of single shape: composed of the same polygon arranged regularly, the length difference of adjacent polygons is not more than 20%, ensuring the symmetry of the structure and uniform stress distribution; (b) combination distribution of multiple shapes: composed of two or more different shapes of polygons arranged in a predetermined pattern, the proportion of each shape of polygon is 10% to 90%, forming a heterogeneous surface structure; (c) zoned differential distribution: the surface of the ball is divided into 2 to 6 zones according to the spherical coordinates, different zones are spliced with polygons of different shapes or sizes, and the boundary between zones is smoothly connected by transition polygons to avoid stress mutation.

6. The polyhedral faceted slotted progressive seal and bridge plug ball of claim 1, wherein, The temporary plugging ball is a hollow temporary plugging ball or a solid temporary plugging ball, the hollow temporary plugging ball is composed of a flexible polyhedral shell, and the solid temporary plugging ball is composed of a ball core and a flexible polyhedral shell.

7. The polyhedral, faceted, progressively sealed, and ball-shaped, temporary plugging device according to claim 6, characterized in that, The thickness H and the edge length L of the flexible polyhedral shell I and the flexible polyhedral shell II are greater than or equal to 0.05D and less than or equal to 0.5D, and D is the circumscribed ball diameter of the flexible polyhedral shell I and the flexible polyhedral shell II.

8. The polyhedral slotted progressive seal and bridge plug ball of claim 7, wherein, The circumscribed ball diameter D is greater than or equal to 5mm and less than or equal to 50mm.

9. The polyhedral slotted progressive seal and bridge plug ball of claim 6, wherein, The ball core is made of degradable material or non-degradable elastic material; the degradable material is any one or more of polylactic acid, polyglycolic acid, polycaprolactone, polyhydroxyalkanoate, and polyvinyl alcohol; the non-degradable elastic material is thermoplastic elastomer or thermosetting elastomer.

10. The polyhedral reentrant progressively sealing temporary plugging ball according to any one of claims 1-9, characterized in that, The elastic modulus of the flexible material is greater than or equal to 0.01GPa and less than or equal to 10GPa, and the Poisson's ratio of the flexible material is greater than or equal to 0.2 and less than or equal to 0.49.

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