A sealing device for fracturing operations and its method of use

Abstract

This invention relates to a sealing device for fracturing operations and its method of use. The sealing device includes: a skeleton ring with outer annular grooves at both ends and an inner annular groove inside, and a skeleton through-hole penetrating its thickness direction; two outer rings disposed within the outer annular grooves, each with an outer annular through-hole penetrating its thickness direction; and an inner ring disposed within the inner annular groove. The high-temperature, high-pressure sealing device for fracturing operations proposed in this invention, made of metallic materials and capable of withstanding temperatures up to 205°C, abandons the conventional method of sealing the lower part of the sealing ring by slotting a mandrel and inserting an O-ring. Instead, it achieves sealing by compressing a non-metallic material—asbestos packing—within the sealing ring. This non-metallic material can withstand temperatures up to 205°C and does not fail in the environment of heavy oil thermal recovery, thus ensuring sealing performance and making it suitable for high-temperature well conditions up to 205°C.

Description

Technical Field

[0001] This invention relates to a sealing device for fracturing operations and its method of use, belonging to the field of oilfield drilling technology. Background Technology

[0002] When extracting oil underground or offshore, the temperature at the bottom of the well can easily exceed 150 degrees Celsius during the extraction process, creating a high-temperature well condition. Since the sealing structures of typical oil extraction tools are usually made of rubber, these rubber seals are prone to failure when the downhole temperature rises, reducing extraction efficiency and increasing costs. This is especially true in stratified injection and production, where the sealing structure of the packer is easily damaged by high temperatures, potentially turning stratified injection and production into mixed production. This not only increases injection and production costs but may also contaminate the oil reservoir, thus reducing production capacity.

[0003] In oil extraction, packers are often used to separate formations to achieve efficient oil production. To improve production efficiency, multiple packers are installed in a single tubing string. These packers are separated by their respective sealing structures to achieve stratified injection and production. However, during stratified injection and production, the sealing structure is prone to failure in the event of high temperature and high pressure conditions.

[0004] In existing sealing devices, the sealing method typically uses both conventional sealing rings and O-rings. Generally, an O-ring is inserted into a groove on the sealing mandrel, and then the sealing ring is fitted onto the O-ring position on the mandrel. Thus, when the packer is operating, the lower part of the sealing ring is sealed by the interference fit between the O-ring and the sealing ring, while the upper part is sealed by the interference fit between the O-ring on the sealing ring and the sealing sleeve. However, because non-metallic materials cannot withstand high temperatures, conventional sealing structures are unsuitable for the high-temperature well conditions generated during heavy oil thermal recovery. Therefore, there is an urgent need to design a sealing structure capable of withstanding high temperatures during fracturing operations. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a sealing device for fracturing operations and its usage method. This device is a high-temperature and high-pressure sealing structure for fracturing operations that can withstand temperatures up to 205°C. This metal module seal serves as an isolation and sealing mechanism during sectional well drilling and segmented gas injection.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A sealing device for fracturing operations, comprising:

[0008] The skeleton ring has outer ring grooves at both ends and inner ring grooves inside, and the skeleton ring has a skeleton through hole that runs through its thickness direction.

[0009] Two outer rings are disposed within the outer ring groove, and each outer ring has a through hole extending through its thickness direction.

[0010] The inner ring is disposed within the inner ring groove.

[0011] Preferably, in the sealing device for fracturing operations, the skeleton through hole and the outer ring through hole are arranged symmetrically along the axis of the skeleton ring and the outer ring.

[0012] Preferably, in the sealing device for fracturing operations, both ends of the skeleton ring are provided with annular flanges, and the annular flanges and the ends of the skeleton ring together define an outer annular groove.

[0013] The sealing device for fracturing operations, preferably, includes a skeleton through hole comprising an oblique hole, a vertical hole, or a curved through hole.

[0014] Preferably, in the sealing device used for fracturing operations, the skeleton through hole is a stepped through hole.

[0015] The sealing device for fracturing operations, preferably, includes an outer ring through hole comprising an oblique hole, a vertical hole, or a curved through hole.

[0016] Preferably, in the sealing device used for fracturing operations, the outer ring through hole is an oblique hole.

[0017] Preferably, the outer ring of the sealing device used in fracturing operations is a copper outer ring.

[0018] Preferably, the inner ring of the sealing device used for fracturing operations is an asbestos packing inner ring.

[0019] The sealing device for fracturing operations, preferably, has a skeleton ring made of 65Mn spring steel.

[0020] A second aspect of the present invention provides a method of using the above-described sealing device for fracturing operations, comprising the following steps:

[0021] The sealing device is installed onto a matching mandrel, which is press-fitted with the inner ring. The inner ring is compressed and expanded, fitting tightly against the mandrel. The mandrel with the sealing device installed is then inserted into a matching sealing cylinder. The sealing cylinder compresses the outer ring, the skeleton ring, and the inner ring. Both the outer ring and the skeleton ring fit against the inner wall of the sealing cylinder, achieving a secondary seal. Simultaneously, as the sealing cylinder reduces the diameter of the sealing device, the through hole of the outer ring decreases, and the through hole of the skeleton ring also shrinks. The two through holes are positioned opposite each other, thus constraining each other during the sealing process and ensuring the sealing performance of the sealing device.

[0022] The present invention has the following advantages due to the adoption of the above technical solutions:

[0023] 1. The high-temperature and high-pressure sealing device for fracturing operations proposed in this invention, which is made of metal materials and can withstand temperatures up to 205°C, abandons the conventional method of slotting the mandrel and inserting an O-ring to seal the lower part of the sealing ring. Instead, it achieves sealing by compressing the non-metallic material—asbestos packing—within the sealing ring. This non-metallic material can withstand temperatures up to 205°C and does not fail in the environment of heavy oil thermal recovery, thus ensuring sealing performance. It is suitable for high-temperature well conditions at 205°C.

[0024] 2. The sealing device involved in this invention uses a slotted copper outer ring and a slotted spring steel frame in the part that contacts the sealing cylinder. In order to ensure the seal, the two slots are 180° apart. After the two are inserted into the sealing cylinder, the sealing cylinder reduces the diameter of the two. The surfaces of the two simultaneously contact the inner surface of the sealing cylinder, resulting in a large sealing area and the ability to withstand a high temperature of 205°C.

[0025] 3. In the device of the present invention, a non-metallic ring is installed in the inner ring groove of the 65Mn spring steel skeleton. The material is asbestos packing. This non-metallic material can withstand a high temperature of 205℃. After the sealing cylinder is inserted into the sealing structure, the seal on the mandrel can be guaranteed, and the material failure under high temperature conditions can be avoided. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a sealing device for high-temperature and high-pressure fracturing operations according to an embodiment of the present invention.

[0027] Figure 2 This is a top view of the sealing device provided in this embodiment of the present invention;

[0028] Figure 3 This is a half-sectional view of the sealing device provided in this embodiment of the present invention;

[0029] Figure 4 This is an exploded view of the sealing device provided in this embodiment of the present invention;

[0030] Figure 5This is a perspective view of the sealing device provided in this embodiment of the present invention when its diameter is reduced;

[0031] The markings in the diagram are as follows:

[0032] 1-Outer ring; 2-Inner ring; 3-Skeleton ring; 4-Skeleton through hole; 5-Outer ring through hole; 6-Outer ring groove; 7-Inner ring groove; 8-Annular flange. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention are described clearly and completely below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0034] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," "third," "fourth," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0035] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "above," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure.

[0036] One existing technology discloses a high-temperature resistant rubber sealing ring, including a high-temperature resistant sealing ring body, a top ring fixed at the upper end of the high-temperature resistant sealing ring body, a bottom ring fixed at the lower end of the high-temperature resistant sealing ring body, two intermediate rings set vertically and vertically embedded and fixed in the high-temperature resistant sealing ring body between the top ring and the bottom ring, the upper intermediate ring being fixedly connected to the top plate, and the lower intermediate ring being fixedly connected to the bottom ring, a convex ring being machined on the inner edge of the high-temperature resistant sealing ring body between the two intermediate rings, and an expansion component being provided at the lower end of the high-temperature resistant sealing ring body inside the bottom ring.

[0037] Another prior art discloses a high-temperature resistant rubber sealing ring, comprising an upper ring and a bottom ring that cooperate with each other. Its characteristic is that radially penetrating elastic reinforcing heat-conducting elements are embedded in the inner and outer sides of the upper and bottom rings for positioning and tight fitting of the cooperating upper and bottom rings. By providing the reinforcing heat-conducting elements of the bimetallic ring, when pressure is applied, the metal ring of the inner ring will compress the inner ring, causing the rubber to deform and fill the gaps; similarly, when the through groove is pressured, the rubber will expand and seal the end side of the connecting piece; since the thermal conductivity of the metal ring is better than that of the rubber, internal heat can be effectively dissipated and discharged through the metal ring of the outer ring; the protrusions and grooves facilitate positioning when the rings are fitted together and enhance the sealing performance of the splicing surfaces.

[0038] The third prior art discloses a wear-resistant and high-pressure resistant sealing ring, including a sealing ring body, a fixing mechanism on the sealing ring body, a reinforcing mechanism on the sealing ring body, and a connection mechanism for connecting to a reaction vessel on the sealing ring body. A first adsorption mechanism for adsorbing onto the reaction vessel lid is installed on the side of the sealing ring body, and a second adsorption mechanism for adsorbing onto the reaction vessel lid is also installed on the sealing ring body. After the sealing ring body comes into contact with the connection mechanism at the reaction vessel, the inner and outer walls of the reaction vessel contact the inner wall of the sealing ring body, thereby achieving adsorption between the first adsorption mechanism and the inner wall of the reaction vessel lid, increasing the connection effect between the sealing ring body and the reaction vessel lid. When installing the sealing ring body onto the reaction vessel lid, the second adsorption mechanism sequentially adsorbs and fixes the sealing ring body to the reaction vessel lid, preventing the sealing ring body from slipping off.

[0039] Based on the above problems, this invention improves existing sealing ring structures and sealing materials, designing a high-temperature and high-pressure sealing structure made of metal material capable of withstanding 205℃ in fracturing operations, specifically for the high-temperature environment of thermal recovery. This structure is used to achieve layered isolation or, during oil production, to achieve internal isolation within the packer during separate production and injection. Compared to conventional sealing rings, the innovation of this metal sealing structure lies in the fact that all materials used in its components can operate in high-temperature environments. Furthermore, it does not use O-rings for sealing; instead, it employs a diameter reduction method, compressing the sealing ring to achieve a seal. This meets the requirements of thermal recovery in offshore oil fields. Moreover, this sealing ring eliminates the need for slotting O-rings on the sealing mandrel, effectively enhancing mandrel strength and reducing the probability of isolation seal failure. This improves unconventional thermal recovery well completion technology, increasing production efficiency and profits.

[0040] like Figure 1 , 3As shown in Figure 4, the sealing device of the present invention includes: an outer ring 1, an inner ring 2, and a skeleton ring 3. Both ends of the skeleton ring 3 are provided with outer ring grooves 6 to accommodate the outer ring 1. An inner ring groove 7 is provided inside the skeleton ring 3 to accommodate the inner ring. The skeleton ring 3 has a skeleton through hole 4 extending through its thickness direction, and the outer ring 1 has an outer ring through hole 5 extending through its thickness direction. Preferably, the skeleton through hole 4 and the outer ring through hole 5 are symmetrically arranged along the axis of the skeleton ring 3 and the outer ring 1. In this way, during use, because the two through holes are positioned opposite each other, the two through holes mutually constrain each other during the sealing process, thereby ensuring the sealing performance of the sealing device.

[0041] In some preferred embodiments of the present invention, such as Figure 4 As shown, both ends of the skeleton ring 3 are provided with annular flanges 8, which together with the ends of the skeleton ring 3 define an outer annular groove 6. The thickness of the annular flange 8 is less than the thickness of the skeleton ring 3, and a stepped outer annular groove 6 is formed between the annular flange 8 and the skeleton ring 3. The outer ring 1 is fitted outside the annular flange 8.

[0042] Furthermore, the skeleton through-hole 4 penetrates the thickness direction of the skeleton ring 3. The skeleton through-hole 4 can be a through-hole of various shapes, such as an oblique hole, a vertical hole, or a curved through-hole. The present invention does not limit its shape. In some preferred embodiments, the skeleton through-hole 4 is preferably an oblique hole or a curved through-hole. The curved through-hole includes an arc-shaped curved through-hole and a broken-line curved through-hole. More preferably, the skeleton through-hole 4 is preferably a stepped through-hole, such as... Figure 4 As shown.

[0043] Furthermore, such as Figure 3 , 4 As shown, the outer ring through-hole 5 also extends through its thickness direction. The outer ring through-hole 5 includes oblique holes, vertical holes, or curved through-holes; the present invention does not limit its shape. In some preferred embodiments, the outer ring through-hole 5 is preferably an oblique hole or a curved through-hole, and the curved through-hole includes arc-shaped curved through-holes and zigzag curved through-holes. More preferably, the outer ring through-hole 5 is preferably an oblique through-hole, such as... Figure 3 As shown.

[0044] In some preferred embodiments of the present invention, the outer ring 1 is preferably a copper outer ring, the inner ring 2 is preferably an asbestos packing inner ring, and the skeleton ring 3 is preferably a 65Mn spring steel skeleton ring.

[0045] The present invention also provides a method of using the above-mentioned sealing device, comprising the following steps:

[0046] The metal sealing device is installed onto the matching mandrel. The mandrel and the asbestos packing inner ring 2 are interference-fitted. The asbestos packing inner ring 2 is compressed and expanded, tightly fitting against the mandrel. Then, the mandrel with the sealing device installed is inserted into the matching sealing cylinder. The sealing cylinder compresses the copper outer ring 1, the 65Mn spring steel skeleton ring 3, and the asbestos packing inner ring 2. At this time, the copper outer ring 1 is in contact with the sealing cylinder, and the 65Mn spring steel skeleton ring 3 is also in contact with the sealing cylinder. Both the copper outer ring 1 and the 65Mn spring steel skeleton ring 3 are in contact with the inner wall of the sealing cylinder, achieving a secondary seal. This process improves the sealing effect. Simultaneously, as the sealing cylinder reduces the diameter of the metal sealing device, the through hole 5 of the copper outer ring decreases, as does the through hole 4 of the 65Mn spring steel skeleton. With the two through holes positioned opposite each other, the through hole 4 on the 65Mn spring steel skeleton and the through hole 5 of the copper outer ring mutually restrain each other during the sealing process, thus ensuring the sealing performance of the sealing ring. Furthermore, the reduction in diameter of the sealing cylinder further compresses the asbestos packing inner ring 2, resulting in a tighter contact with the sealing mandrel, also ensuring a good seal.

[0047] The sealing device disclosed in this invention uses an open-hole copper outer ring 1 and an open-hole spring steel skeleton ring 3 in contact with the sealing cylinder. In order to ensure the seal, the two holes are 180° apart. After the two are inserted into the sealing cylinder, the sealing cylinder reduces the diameter of the two. The surfaces of the two contact the inner surface of the sealing cylinder at the same time, resulting in a large sealing area and the ability to withstand a high temperature of 205°C.

[0048] The present invention installs a non-metallic ring (inner ring 2) in the inner ring groove 7 of the 65Mn spring steel skeleton. The material is asbestos packing. This non-metallic material can withstand a high temperature of 205℃. After the sealing device is inserted into the sealing cylinder, the sealing on the mandrel can be guaranteed, and the material failure under high temperature conditions can be avoided.

[0049] The metal module sealing device disclosed in this invention is used to provide an isolation and sealing function during directional well layered mining and segmented gas injection. The sealing device is inserted into the sealing cylinder of the isolation packer. By reducing the diameter of the sealing cylinder, the sealing device shrinks. The non-metallic material—asbestos packing inner ring 2—in the inner annular groove of the sealing device is tightly attached to the mandrel. At the same time, the metallic material—copper outer ring 1—on the outer annular groove 6 of the sealing device and the 65Mn spring steel skeleton ring 3 of the sealing device are also compressed and fit against the sealing cylinder, thereby achieving a sealing effect.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention 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 of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sealing device for fracturing operations, characterized in that, include: The skeleton ring (3) has outer ring grooves (6) at both ends and inner ring grooves (7) inside. The skeleton ring (3) has a skeleton through hole (4) that runs through its thickness direction. Two outer rings (1) are provided in the outer ring groove (6), and the outer rings (1) are provided with outer ring through holes (5) that penetrate their thickness direction. Inner ring (2) is disposed within the inner ring groove (7); The outer ring (1) is a copper outer ring; The inner ring (2) is an asbestos packing inner ring, and the skeleton ring (3) is a 65Mn spring steel skeleton ring.

2. The sealing device for fracturing operations according to claim 1, characterized in that, The skeleton through hole (4) and the outer ring through hole (5) are arranged symmetrically along the axis of the skeleton ring (3) and the outer ring (1).

3. The sealing device for fracturing operations according to claim 1 or 2, characterized in that, Both ends of the skeleton ring (3) are provided with annular flanges (8), and the annular flanges (8) and the ends of the skeleton ring (3) together define an outer annular groove (6).

4. The sealing device for fracturing operations according to claim 1 or 2, characterized in that, The skeleton through hole (4) includes oblique hole, vertical hole or curved through hole.

5. The sealing device for fracturing operations according to claim 4, characterized in that, The skeleton through hole (4) is a stepped through hole.

6. The sealing device for fracturing operations according to claim 1 or 2, characterized in that, The outer ring through hole (5) includes an oblique hole, a vertical hole, or a curved through hole.

7. The sealing device for fracturing operations according to claim 6, characterized in that, The outer ring through hole (5) is an oblique hole.

8. A method of using a sealing device for fracturing operations as described in any one of claims 1-7, characterized in that, Includes the following steps: The sealing device is installed on the matching mandrel. The mandrel is press-fitted with the inner ring (2). The inner ring (2) is compressed and expanded, and fits tightly against the mandrel. Then, the mandrel with the sealing device installed is inserted into the matching sealing cylinder. The sealing cylinder compresses the outer ring (1), the skeleton ring (3), and the inner ring (2). The outer ring (1) and the skeleton ring (3) fit against the inner wall of the sealing cylinder, achieving a secondary sealing effect. At the same time, while the sealing cylinder reduces the diameter of the sealing device, the outer ring through hole (5) decreases, and the skeleton through hole (4) also shrinks. The outer ring through hole (5) and the skeleton through hole (4) are positioned opposite each other. This makes the outer ring through hole (5) and the skeleton through hole (4) mutually restrict each other during the sealing process, thereby ensuring the sealing performance of the sealing device.

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