Centralizer with sealing compensation function

Abstract

The invention relates to the technical field of oil and gas well cementing tools, in particular to a centralizer with a sealing compensation function, and aims to solve the technical problem that hidden danger points are generated in casing welt sealing due to the fact that the bonding strength between the centralizer and a cement sheath is lower than the bonding strength of the cement sheath in the prior art. The centralizer with the sealing compensation function comprises an end ring, a centralizing body and a first sealing body. And the first sealing body is made of an oil and water self-expanding material. According to the centralizer with the sealing compensation function, the first sealing body made of the material capable of expanding when encountering oil and water is fixedly connected to the end ring and enters a well along with a sleeve, oil-gas-water media flowing upwards along the channeling channel are absorbed through the first sealing body, plugging of the channeling channel is completed through expansion of the first sealing body, and hidden danger points of sealing of the edge of the sleeve are eliminated. The technical problem that in an existing integral elastic centralizer, due to the fact that the bonding strength between the centralizer and a cement sheath is lower than the bonding strength of the cement sheath, hidden danger points are generated in casing welt sealing is solved.

Description

Technical Field

[0001] This invention relates to the field of cementing tools for oil and gas wells, and in particular to a centralizer with a sealing compensation function. Background Technology

[0002] When drilling operations extend into deeper formations, fracturing, perforation, and irregular wellbore patterns often lead to micro-annular gaps and micro-cracks in the cement sheath. This can cause potential problems in the casing edge seal, increasing the risk of oil, gas, and water cross-contamination and affecting wellbore sealing and stability. The centralizer, as part of the running tubing string, is located around the casing and sealed within the cement sheath, forming part of the casing edge seal structure. However, the bond strength between the centralizer and the cement sheath is lower than the bond strength of the cement sheath itself. This difference makes the bond between the centralizer and the cement sheath prone to failure under the influence of pressure changes, temperature changes, or mechanical vibrations, leading to micro-annular gaps and ultimately, potential problems in the casing edge seal.

[0003] The existing centralizer has a technical problem: the bonding strength between the centralizer and the cement ring is lower than the bonding strength of the cement ring itself, which leads to potential problems in the sealing of the sleeve edge. Summary of the Invention

[0004] The purpose of this invention is to provide a centralizer with a sealing compensation function to overcome the technical problem in related technologies where the bonding strength between the centralizer and the cement ring is lower than the bonding strength of the cement ring itself, resulting in potential problems in the sealing of the sleeve edge.

[0005] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: The centralizer with sealing compensation function provided by this invention includes: The support body includes an end ring and a centralizing body. The end ring is fitted onto the casing, and the centralizing body abuts against the well wall to keep the casing centered relative to the wellbore. The end ring has a positioning groove, and the sealing compensation component is fixed to the positioning groove. The sealing compensation component includes a first sealing body, which is made of a self-expanding material that reacts with oil and water. When microcracks form in the cement sheath and a flow channel is created, the first sealing body can absorb the oil, gas, and water media flowing up along the flow channel, expand, and seal the flow channel.

[0006] Specifically, the first sealing body is installed in the positioning groove by curing through vulcanization.

[0007] Specifically, the plurality of positioning grooves and the sealing compensation elements are arranged along the axial direction of the end ring.

[0008] Specifically, the sealing compensation component further includes a second sealing body, which is made of hot-melt resin or fusible metal and is installed in the positioning groove by hot-melt curing. A heating device is lowered into the wellbore to heat the second sealing body, so that the second sealing body is fully melted and flows into the flow channel. The heating device is turned off, and the second sealing body cools down naturally and solidifies with the cement ring, completing the gap sealing.

[0009] Specifically, the positioning groove is configured as a composite groove structure comprising an inner annular groove and an outer annular groove, wherein the inner annular groove and the outer annular groove are positioned symmetrically and have equal wall thicknesses. Multiple sets of staggered through holes are evenly distributed in the tube area between the inner and outer annular grooves, and these through holes connect the inner and outer annular grooves. During vulcanization, the first sealing body can flow through the through holes. During hot-melt processing, the second sealing body can flow through the through holes.

[0010] Specifically, the first sealing body and the second sealing body are staggered along the axial direction of the end ring to improve sealing uniformity and stability.

[0011] Specifically, the centralizing body includes multiple bow segments evenly distributed around the axis of the end ring, the bow segments being configured as arcs connecting the two end rings, and the maximum outer diameter of the centralizing body being greater than or equal to the standard diameter of the wellbore.

[0012] Specifically, the bow plate adopts a non-uniform thickness structure, gradually thinning from the two ends connected to the end ring towards the middle.

[0013] Specifically, the end ring and the bow plate are configured as an integral structure.

[0014] Specifically, it also includes a wear-resistant strip, which is disposed in the thinned area in the middle of the bow piece to improve the wear resistance of the bow piece.

[0015] Based on the above technical solutions, the beneficial effects of the present invention are analyzed as follows: This invention provides a centralizer with a sealing compensation function, comprising: The support body includes an end ring and a centralizing body. The end ring is fitted onto the casing, and the centralizing body abuts against the well wall to keep the casing centered relative to the wellbore. The end ring has a positioning groove, and the sealing compensation component is fixed to the positioning groove. The sealing compensation component includes a first sealing body, which is made of a self-expanding material that reacts with oil and water. When microcracks form in the cement sheath and a flow channel is created, the first sealing body can absorb the oil, gas, and water media flowing up along the flow channel, expand, and seal the flow channel.

[0016] In practical applications, the support body, to which the first sealing body is fixed, is fitted onto the casing and lowered into the well along with the casing. The centralizing body maintains the casing centered relative to the wellbore by abutting against the well wall. After the casing is lowered and cementing is completed, the support body is sealed within a cement sheath. When microcracks appear in the cement sheath and form a flow channel, the first sealing body can absorb the oil, gas, and water media flowing upwards along the flow channel, complete its expansion, and seal the flow channel.

[0017] As can be seen, compared with existing technologies, this centralizer with sealing compensation function fixes the first sealing body, made of an oil- and water-swellable material, to the end ring and inserts it into the well along with the casing. The first sealing body absorbs the oil, gas, and water media flowing upwards along the crossflow channel, and the expansion of the first sealing body seals the crossflow channel, eliminating the potential sealing problem at the casing edge. This overcomes the technical problem of existing integral elastic centralizers where the bonding strength between the centralizer and the cement sheath is lower than the bonding strength of the cement sheath itself, leading to potential sealing problems at the casing edge. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a centralizer with sealing compensation function provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the supporting structure; Figure 3 This is a cross-sectional schematic diagram of the positioning groove and the first sealing body; Figure 4 A schematic diagram of the cross-sectional structure at the first sealing body; Figure 5 This is a schematic diagram of the cross-sectional structure at the second sealing body.

[0020] icon: 100. Support body; 110. End ring; 101. Positioning groove; 102. Through hole; 120. Straightening body; 121. Bow plate; 200. Sealing compensation component; 210. First sealing body; 220. Second sealing body; 300. Wear-resistant belt. Detailed Implementation

[0021] 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.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0024] The existing integral elastic centralizer has a technical problem: the bonding strength between the centralizer and the cement ring is lower than the bonding strength of the cement ring itself, which leads to potential problems in the sealing of the sleeve edge.

[0025] In view of this, the present invention provides a centralizer with a sealing compensation function, comprising: The support body 100 and the sealing compensation component 200 are included. The support body 100 includes an end ring 110 and a centralizing body 120. The end ring 110 is fitted onto the casing, and the centralizing body 120 abuts against the well wall to keep the casing centered relative to the wellbore. The end ring 110 has a positioning groove 101, and the sealing compensation component 200 is fixed to the positioning groove 101. The sealing compensation component 200 includes a first sealing body 210, which is made of a self-expanding material that is exposed to oil and water. When micro-cracks occur in the cement sheath and a flow channel is formed, the first sealing body 210 can absorb the oil, gas, and water media flowing up along the flow channel, complete its expansion, and seal the flow channel.

[0026] In summary, the centralizer with sealing compensation function provided by this invention can achieve the following technical effects: This centralizer with sealing compensation function fixes a first sealing body 210, made of oil- and water-reactive self-expanding material, to the end ring 110 and inserts it into the well along with the casing. The first sealing body 210 absorbs the oil, gas, and water media that flow upwards along the channel, and the expansion of the first sealing body 210 seals the channel, eliminating the potential sealing problem of casing edge contact. This overcomes the technical problem of existing integral elastic centralizers where the bonding strength between the centralizer and the cement sheath is lower than the bonding strength of the cement sheath itself, leading to potential sealing problems of casing edge contact.

[0027] The following combination Figures 1 to 5 The structure and shape of the centralizer with sealing compensation function provided in this embodiment are described in detail below: In this embodiment, the first sealing body 210 is cured and installed in the positioning groove 101 by vulcanization to prevent it from falling off axially or circumferentially under external force.

[0028] To enhance the sealing effect of the sealing compensation component 200, in this embodiment, multiple positioning grooves 101 and the sealing compensation component 200 are arranged along the axial direction of the end ring 110.

[0029] To prevent the first sealing body 210 from aging and failing due to prolonged wellbore operation, thus losing its sealing function, the sealing compensation component 200 in this embodiment further includes a second sealing body 220. The second sealing body 220 is made of hot-melt resin or fusible metal and is installed in the positioning groove 101 by hot-melting. A heating device is lowered into the wellbore to heat the second sealing body 220, causing it to fully melt and flow into the flow channel. The heating device is then turned off, allowing the second sealing body 220 to cool naturally and solidify with the cement ring, completing the gap sealing.

[0030] To enhance the connection strength between the sealing compensation component 200 and the end ring 110, in this embodiment, the positioning groove 101 is configured as a composite groove structure comprising an inner ring groove and an outer ring groove. The inner and outer ring grooves are positioned identically and have equal wall thicknesses. Multiple sets of staggered through holes 102 are evenly distributed in the tube area between the inner and outer ring grooves, connecting the inner and outer ring grooves. During vulcanization, the first sealing body 210 can flow through the through holes 102. During hot-melt processing, the second sealing body 220 can flow through the through holes 102. The cured first and second sealing bodies 210 and 220 both have the same inner and outer diameter dimensions as the end ring 110.

[0031] In order to enhance the uniformity and stability of the sealing effect and improve adaptability to complex environments, in this embodiment, the first sealing body 210 and the second sealing body 220 are staggered along the axial direction of the end ring 110 to improve the uniformity and stability of the sealing.

[0032] Regarding the structural composition of Fuzheng 120, specifically: The centralizing body 120 includes multiple bow pieces 121 evenly distributed around the axis of the end ring 110. The bow pieces 121 are configured as arcs connecting two end rings 110. The maximum outer diameter of the centralizing body 120 is greater than or equal to the standard diameter of the wellbore. The arc-shaped center of each bow piece 121 abuts against the well wall. Through the reaction force of the abutment, the end ring 110 and the casing are kept centered in the wellbore, thereby completing the centralization of the casing.

[0033] In this embodiment, the bow plate 121 adopts a non-uniform thickness structure, gradually thinning from both ends connected to the end ring 110 towards the middle. The end regions are used to provide greater reset force, while the middle region is more easily compressed and deformed to reduce the starting force and lowering force, thereby reducing the problem of increased friction during tube string insertion caused by excessive starting force and lowering force.

[0034] In this embodiment, the end ring 110 and the bow plate 121 are set as an integral structure and are formed with equal width by processes such as turning, wire cutting and stamping.

[0035] In this embodiment, a wear-resistant strip 300 is also included. The wear-resistant strip 300 is disposed in the thinned area in the middle of the bow piece 121 to improve the wear resistance of the bow piece 121. The wear-resistant strip 300 may be made of a wear-resistant coating such as a sprayed tungsten carbide powder coating.

[0036] In summary, the specific working process of the centralizer with sealing compensation function provided in this embodiment is as follows: The first sealing body 210 and the second sealing body 220 are sequentially cured and installed in the positioning groove 101 by vulcanization and hot-melt methods, respectively, with the first sealing body 210 and the second sealing body 220 arranged alternately. The cured first sealing body 210 and the second sealing body 220 are trimmed to ensure that their inner and outer diameters match those of the end ring 110. A tungsten carbide powder coating is sprayed onto the outer wall surface of the middle portion of the bow plate 121.

[0037] The end ring 110 is fitted onto the casing and lowered into the well along with the casing. The bow plate 121, through the abutment reaction between the wear-resistant strip 300 and the well wall, acts on the end ring 110 and the casing, keeping the casing centered relative to the wellbore. After the casing is lowered and cemented, the support body 100 is sealed into the cement sheath.

[0038] Fracturing, perforation operations, and irregular wellbore conditions can cause pressure, temperature, or mechanical vibrations, which in turn can lead to micro-annular gaps and micro-cracks in the cement sheath, forming flow channels that allow oil, gas, and water to flow upwards, affecting the wellbore's sealing and stability.

[0039] When the oil, gas and water medium flows upward along the crossflow channel and reaches the first sealing body 210, the first sealing body 210 expands by absorbing the oil, gas and water medium and blocks the crossflow channel.

[0040] When the wellbore operation cycle is too long, the first sealing body 210 may fail to perform its sealing function due to aging. In this case, a heating device is installed inside the wellbore to heat the second sealing body 220, so that the second sealing body 220 is fully melted and flows into the flow channel. The heating device is then turned off, and the second sealing body 220 cools down naturally and solidifies with the cement ring, completing the gap sealing.

[0041] 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 or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A centralizer with sealing compensation function, characterized in that, include: Support body (100) and sealing compensation element (200); The support (100) includes an end ring (110) and a centering body (120). The end ring (110) is sleeved on the casing, and the centering body (120) abuts against the well wall to keep the casing centered about the wellbore. The end ring (110) is provided with a positioning groove (101), and the sealing compensation member (200) is fixedly connected to the positioning groove (101). The sealing compensation component (200) includes a first sealing body (210), which is made of a material that expands when exposed to oil and water. When the cement ring develops microcracks and forms a flow channel, the first sealing body (210) can absorb the oil, gas and water medium flowing up along the flow channel to complete the expansion and seal the flow channel.

2. The centralizer with sealing compensation function according to claim 1, characterized in that: The first sealing body (210) is installed in the positioning groove (101) by curing through vulcanization.

3. The centralizer with sealing compensation function according to claim 2, characterized in that: The plurality of the positioning grooves (101) and the sealing compensation element (200) are arranged along the axial direction of the end ring (110).

4. The centralizer with sealing compensation function according to claim 3, characterized in that: The sealing compensation component (200) further includes a second sealing body (220), which is made of hot melt resin or fusible metal and is installed in the positioning groove (101) by hot melting. A heating device is lowered into the wellbore to heat the second sealing body (220) so that the second sealing body (220) is fully melted and flows into the crossflow channel; After the heating device is turned off, the second sealing body (220) cools down naturally and solidifies with the cement ring, thus completing the gap sealing.

5. The centralizer with sealing compensation function according to claim 4, characterized in that: The positioning groove (101) is configured as a composite groove structure including an inner ring groove and an outer ring groove, wherein the inner ring groove and the outer ring groove are in the same position and have the same wall thickness; Multiple sets of intersecting through holes (102) are evenly distributed in the tube area between the inner ring groove and the outer ring groove. The through holes (102) are used to connect the inner ring groove and the outer ring groove. During vulcanization, the first sealing body (210) can flow through the through hole (102); During the hot-melting process, the second sealing body (220) can flow through the through hole (102).

6. The centralizer with sealing compensation function according to claim 4, characterized in that: The first sealing body (210) and the second sealing body (220) are staggered along the axial direction of the end ring (110) to improve the uniformity and stability of the seal.

7. The centralizer with sealing compensation function according to claim 1, characterized in that: The centralizer (120) includes a plurality of bow pieces (121) evenly distributed around the axis of the end ring (110). The bow pieces (121) are configured as arcs connecting the two end rings (110). The maximum outer diameter of the centralizer (120) is greater than or equal to the standard diameter of the wellbore.

8. The centralizer with sealing compensation function according to claim 7, characterized in that: The bow plate (121) has a non-uniform thickness structure, gradually thinning from the two ends connected to the end ring (110) towards the middle.

9. The centralizer with sealing compensation function according to claim 7, characterized in that: The end ring (110) and the bow plate (121) are configured as an integral structure.

10. The centralizer with sealing compensation function according to claim 7, characterized in that: It also includes a wear-resistant strip (300), which is disposed in the middle thinning area of ​​the bow piece (121) to improve the wear resistance of the bow piece (121).

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