Centralizer with sealing compensation function

Abstract

This invention relates to the field of cementing tools for oil and gas wells, and particularly to a centralizer with a sealing compensation function. It aims to overcome the technical problem in related technologies where the bond strength between the centralizer and the cement sheath is lower than the bond strength of the cement sheath itself, leading to potential sealing issues at the casing edge. The centralizer with sealing compensation function includes: an end ring, a centralizer body, and a first sealing body. The first sealing body is made of a self-expanding material that reacts with oil and water. This centralizer with sealing compensation function fixes the self-expanding first sealing body, made of oil and water, to the end ring and inserts it into the well with the casing. The first sealing body absorbs the oil, gas, and water media that flow upwards along the channel, and the expansion of the first sealing body seals the channel, eliminating potential sealing issues at the casing edge. This overcomes the technical problem of existing integral elastic centralizers where the bond strength between the centralizer and the cement sheath is lower than the bond strength of the cement sheath itself, leading to potential sealing issues at the casing edge.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cementing tools for oil and gas wells, and particularly relates to a centralizer with sealing compensation function. BACKGROUND

[0002] When drilling operations advance to deep formations, fracturing, perforating operations and irregular boreholes often cause micro annulus and micro cracks in the cement sheath, which in turn causes hidden points in the casing shoulder seal, increases the risk of oil and gas water channeling, and affects the sealing and stability of the wellbore. As part of the running string, the centralizer is located on the outer periphery of the casing and is sealed in the cement sheath, becoming a component of the casing shoulder seal structure. However, the bonding strength between the centralizer and the cement sheath is lower than the bonding strength of the cement sheath itself, and this difference makes the bonding between the centralizer and the cement sheath easily fail under the influence of pressure changes, temperature changes or mechanical vibrations, thereby causing micro annulus and in turn causing hidden points in the casing shoulder seal.

[0003] The existing centralizer has the technical problem of causing hidden points in the casing shoulder seal due to the bonding strength between the centralizer and the cement sheath being lower than the bonding strength of the cement sheath itself. SUMMARY

[0004] The purpose of the present application is to provide a centralizer with sealing compensation function to overcome the technical problem of causing hidden points in the casing shoulder seal due to the bonding strength between the centralizer and the cement sheath being lower than the bonding strength of the cement sheath itself in the related art.

[0005] To solve the above technical problems, the technical solution provided by the present application is as follows:

[0006] The centralizer with sealing compensation function provided by the present application comprises:

[0007] A support body and a sealing compensation member. The support body comprises an end ring and a centralizing body, the end ring is sleeved on the casing, and the centralizing body abuts against the well wall for keeping the casing centered about the wellbore. The end ring is provided with a positioning groove, and the sealing compensation member is fixedly connected to the positioning groove. The sealing compensation member comprises a first sealing body, and the first sealing body is made of a material that swells when it comes into contact with oil or water. When the cement sheath produces micro cracks and forms a channeling channel, the first sealing body can absorb the oil, gas and water medium channeling along the channeling channel to complete swelling and block the channeling channel.

[0008] Specifically, the first sealing body is installed in the positioning groove by vulcanization.

[0009] Specifically, a plurality of positioning grooves and sealing compensation members are arranged along the axial direction of the end ring.

[0010] Specifically, the sealing compensation member further comprises a second sealing body, which is made of hot-melt resin or fusible metal and is installed in the positioning groove by hot-melt method. The second sealing body is heated by a heating device in the wellbore to melt and flow into the channel. The heating device is turned off, and the second sealing body is cooled naturally and integrated with the cement sheath to complete the gap sealing.

[0011] Specifically, the positioning groove is provided as a composite groove structure comprising an inner ring groove and an outer ring groove, the inner ring groove is consistent with the outer ring groove in position and equal in groove wall thickness. The pipe body area between the inner ring groove and the outer ring groove is uniformly distributed with multiple groups of staggered through holes, which are used to connect the inner ring groove and the outer ring groove. During vulcanization, the first sealing body can flow through the through holes. During hot-melt, the second sealing body can flow through the through holes.

[0012] Specifically, the first sealing body and the second sealing body are staggered along the axial direction of the end ring to improve the uniformity and stability of sealing.

[0013] Specifically, the centralizer comprises a plurality of arch pieces uniformly distributed around the axis of the end ring, the arch pieces are arranged in an arc shape between the two end rings, and the maximum outer diameter of the centralizer is greater than or equal to the standard diameter of the wellbore.

[0014] Specifically, the arch pieces adopt a non-equal-thickness structure, which gradually thins from both ends connected to the end ring to the middle.

[0015] Specifically, the end ring and the arch piece are arranged in an integrated structure.

[0016] Specifically, it further comprises a wear-resistant band arranged in the thinned middle area of the arch piece to improve the wear resistance of the arch piece.

[0017] The beneficial effects of the above technical solutions are analyzed as follows:

[0018] The present application provides a centralizer with sealing compensation function, comprising:

[0019] A support body and a sealing compensation member. The support body comprises an end ring and a centralizer, the end ring is sleeved on the casing, and the centralizer abuts against the well wall to keep the casing centered about the wellbore. The end ring is provided with a positioning groove, and the sealing compensation member is fixedly connected to the positioning groove. The sealing compensation member comprises a first sealing body made of a material that expands when it comes into contact with oil or water. When the cement sheath has micro-cracks and forms a channel, the first sealing body can absorb the oil, gas and water medium flowing along the channel to complete expansion and seal the channel.

[0020] In specific application, the support body with the first sealing body fixed thereon is sleeved on the casing, and is lowered into the well together with the casing. The centralizer keeps the casing centered about the wellbore by abutting against the well wall. After the casing is lowered and cementing is completed, the support body is sealed in the cement sheath. When the cement sheath has micro-cracks and forms a channel for channeling, the first sealing body can absorb the oil, gas and water medium channeling along the channel and complete expansion, and block the channel.

[0021] It can be seen that, compared with the prior art, the centralizer with sealing compensation function fixes the first sealing body made of oil and water self-expanding material on the end ring and lowers into the well together with the casing. The first sealing body absorbs the oil, gas and water medium channeling along the channel, and blocks the channel through expansion of the first sealing body, eliminating the hidden danger of casing edge sealing. The technical problem that the existing integral elastic centralizer has a bonding strength between the centralizer and the cement sheath lower than the bonding strength of the cement sheath itself, resulting in a hidden danger of casing edge sealing, is overcome. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0023] Figure 1 The structural schematic diagram of the centralizer with sealing compensation function provided by the embodiments of the present application is shown in the figure.

[0024] Figure 2 The structural schematic diagram of the support body is shown in the figure.

[0025] Figure 3 The sectional structural schematic diagram of the positioning groove and the first sealing body is shown in the figure.

[0026] Figure 4 The sectional structural schematic diagram at the first sealing body is shown in the figure.

[0027] Figure 5 The sectional structural schematic diagram at the second sealing body is shown in the figure.

[0028] FIG.

[0029] 100, support body; 110, end ring; 101, positioning groove; 102, through hole; 120, centralizer; 121, bow piece;

[0030] 200, sealing compensation member; 210, first sealing body; 220, second sealing body;

[0031] 300. Wear-resistant tape. DETAILED DESCRIPTION

[0032] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by a person of ordinary skill in the art without creative labor based on the embodiments in the present application belong to the scope of protection of the present application.

[0034] Some embodiments of the present application will be described in detail below with reference to the drawings. The following embodiments and features in the embodiments can be combined with each other without conflict.

[0035] The existing integral elastic centralizer has the technical problem that the bonding strength between the centralizer and the cement sheath is lower than the bonding strength of the cement sheath itself, which causes a hidden danger point of the casing to be sealed.

[0036] Therefore, the present application provides a centralizer with sealing compensation function, comprising:

[0037] The support body 100 and the sealing compensation piece 200. The support body 100 comprises an end ring 110 and a centralizing body 120, the end ring 110 is sleeved on the casing, the centralizing body 120 abuts against the well wall, and is used for keeping the casing centered about the wellbore. The end ring 110 is provided with a positioning groove 101, and the sealing compensation piece 200 is fixedly connected to the positioning groove 101. The sealing compensation piece 200 comprises a first sealing body 210, and the first sealing body 210 is made of an oil and water swelling material. When the cement sheath has micro-cracks and forms a channeling channel, the first sealing body 210 can absorb the oil, gas and water medium channeling along the channeling channel to complete swelling, and block the channeling channel.

[0038] In combination with the above technical solutions, the centralizer with sealing compensation function provided by the present application can achieve the following technical effects:

[0039] The centralizer with the sealing compensation function will be connected with the first sealing body 210 made of the self-expanding material meeting oil and water and will be put into the well with the casing, the oil, gas and water medium flowing along the channel will be absorbed by the first sealing body 210, and the channel will be blocked by the expansion of the first sealing body 210, and the hidden danger of the casing sealing will be eliminated. The technical problem that the existing whole elastic centralizer has the bonding strength between the centralizer and the cement ring lower than the bonding strength of the cement ring, resulting in the hidden danger of the casing sealing.

[0040] The structure and shape of the centralizer with the sealing compensation function provided by the embodiment will be described in detail as follows: Figures 1 to 5 The structure and shape of the centralizer with the sealing compensation function provided by the embodiment will be described in detail as follows:

[0041] In the scheme of the embodiment, the first sealing body 210 is installed in the positioning groove 101 by vulcanization, so as to avoid falling off from the axial direction or the circumferential direction under the action of external force.

[0042] In order to enhance the sealing effect of the sealing compensation part 200, in the scheme of the embodiment, the plurality of positioning grooves 101 and the sealing compensation part 200 are arranged along the axial direction of the end ring 110.

[0043] In order to avoid the aging failure of the first sealing body 210 due to the long running period of the wellbore, so as to fail to play a sealing role, in the scheme of the embodiment, the sealing compensation part 200 further comprises a second sealing body 220, the second sealing body 220 is selected from a hot melt resin or a 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 channel. The heating device is turned off, the second sealing body 220 is naturally cooled and solidified with the cement ring, and the gap sealing is completed.

[0044] In order to improve the connection strength of the sealing compensation part 200 and the end ring 110, in the scheme of the embodiment, the positioning groove 101 is provided as a composite groove structure comprising an inner ring groove and an outer ring groove, the inner ring groove and the outer ring groove are consistent in position and equal in groove wall thickness. The pipe body region between the inner ring groove and the outer ring groove is uniformly distributed with a plurality of groups of staggered through holes 102, the through holes 102 are used for connecting the inner ring groove and the outer ring groove. During vulcanization, the first sealing body 210 can flow through the through holes 102. During hot melting, the second sealing body 220 can flow through the through holes 102. The solidified first sealing body 210 and the second sealing body 220 are consistent with the inner diameter and the outer diameter of the end ring 110.

[0045] In order to enhance the uniformity and stability of the sealing effect and the adaptability to complex environment, in the scheme of the embodiment, the first sealing body 210 and the second sealing body 220 are arranged in the axial direction of the end ring 110, so as to improve the uniformity and stability of the sealing.

[0046] Regarding the structural composition of the centralizer 120, specifically:

[0047] The centralizer 120 includes a plurality of arches 121 evenly distributed around the axis of the end ring 110, and the arches 121 are arranged in an arc shape between 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. The central part of each arch 121 abuts against the well wall, and through the abutting reaction, the end ring 110 and the casing are kept centered in the wellbore, thereby completing the centralization of the casing.

[0048] In the scheme of the present embodiment, the arches 121 adopt a non-uniform thickness structure, gradually thinning from both ends connected to the end ring 110 to the middle. The end region is used to provide greater restoring force, and the middle region is more easily compressed and deformed, used to reduce the starting force and running force, thereby reducing the problem of increased pipe string running friction caused by excessive starting force and running force.

[0049] In the scheme of the present embodiment, the end ring 110 and the arch 121 are arranged in an integrated structure, and are formed by processes such as turning, wire cutting, and stamping.

[0050] In the scheme of the present embodiment, it also includes a wear-resistant band 300, which is arranged in the thinned middle region of the arch 121, used to improve the wear resistance of the arch 121. Among them, the wear-resistant band 300 can be selected from a sprayed tungsten carbide powder coating and other wear-resistant coatings.

[0051] In summary, the specific working process of the centralizer with sealing compensation function provided in the present embodiment is as follows:

[0052] The first sealing body 210 and the second sealing body 220 are sequentially installed in the positioning groove 101 by vulcanization and hot melting methods respectively, and the first sealing body 210 and the second sealing body 220 are arranged alternately. The first sealing body 210 and the second sealing body 220 after curing are trimmed to make the first sealing body 210 and the second sealing body 220 consistent with the inner and outer diameter dimensions of the end ring 110. A tungsten carbide powder coating is sprayed on the outer wall surface of the middle part of the arch 121.

[0053] The end ring 110 is sleeved on the casing and is run into the well with the casing. The arch 121 is abutted against the well wall through the wear-resistant band 300, and the reaction is applied to the end ring 110 and the casing, so that the casing is kept centered about the wellbore. After the casing is run and cementing is completed, the support body 100 is also sealed in the cement ring.

[0054] Fracturing, perforating operations, and irregular wellbores and other factors cause pressure changes, temperature changes, or mechanical vibrations, which in turn cause microannulus and microcracks in the cement ring, forming a channeling channel, so that oil, gas, and water media channel along the channeling channel, affecting the sealing and stability of the wellbore.

[0055] When the oil-gas-water medium reaches the first sealing body 210 along the channel, the first sealing body 210 expands by absorbing the oil-gas-water medium and blocks the channel.

[0056] When the wellbore operation cycle is too long, the first sealing body 210 may fail to seal due to aging, and the 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 channel. After the heating device is turned off, the second sealing body 220 naturally cools down and is solidified with the cement sheath, and the gap sealing is completed.

[0057] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A centralizer having a seal compensation function, characterized by, The application relates to a centralizer with a sealing compensation function. The centralizer comprises a support body (100) and a sealing compensation part (200). The support body (100) comprises an end ring (110) and a centralizer body (120), the end ring (110) is sleeved on a casing, and the centralizer body (120) abuts against a well wall and is used for keeping the casing centered about a wellbore. The end ring (110) is provided with a positioning groove (101), and the sealing compensation part (200) is fixedly connected to the positioning groove (101). The sealing compensation part (200) comprises a first sealing body (210), and the first sealing body (210) is made of a material that can self-expand when meeting oil and water. When a micro-crack is generated in a cement sheath and a channeling channel is formed, the first sealing body (210) can absorb oil, gas and water media flowing along the channeling channel, complete expansion and block the channeling channel. The sealing compensation part (200) further comprises a second sealing body (220), the second sealing body (220) is made of a heat-meltable resin or a meltable metal and is installed in the positioning groove (101) through a heat-melting mode. 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 channeling channel. The heating device is turned off, the second sealing body (220) is naturally cooled and is integrated with the cement sheath to complete crack blocking. The positioning groove (101) is provided with a composite groove structure comprising an inner ring groove and an outer ring groove, the inner ring groove is consistent with the outer ring groove in position and the groove wall thicknesses are equal. A plurality of groups of staggered through holes (102) are uniformly distributed in the pipe body region between the inner ring groove and the outer ring groove, and the through holes (102) are used for connecting the inner ring groove and the outer ring groove. During vulcanization, the first sealing body (210) can flow through the through holes (102). During heat melting, the second sealing body (220) can flow through the through holes (102).

2. The centralizer with a sealing compensation function according to claim 1, wherein the first sealing body (210) is installed in the positioning groove (101) through a vulcanization mode.

3. The centralizer with a sealing compensation function according to claim 2, wherein a plurality of the positioning grooves (101) and the sealing compensation part (200) are arranged along the axial direction of the end ring (110).

4. The centralizer with a sealing compensation function according to claim 1, wherein the first sealing body (210) and the second sealing body (220) are staggered along the axial direction of the end ring (110) to improve sealing uniformity and stability.

5. The centralizer with a sealing compensation function according to claim 1, wherein the centralizer body (120) comprises a plurality of bow pieces (121) which are uniformly distributed around the axis of the end ring (110), the bow pieces (121) are arranged in an arc shape between two end rings (110), and the maximum outer diameter of the centralizer body (120) is greater than or equal to the standard diameter of a wellbore.

6. The centralizer with a sealing compensation function according to claim 5, wherein ​ ​ ​ ​ The arch piece (121) is of a non-equal thickness structure, gradually thinning from the two ends connected with the end ring (110) to the middle.

7. The centralizer with sealing compensation function according to claim 5, characterized in that: The end ring (110) and the arch piece (121) are arranged in an integrated structure.

8. The centralizer with sealing compensation function according to claim 5, characterized in that: Further comprising a wear-resistant band (300) arranged at the thinned middle region of the arch piece (121) to improve the wear resistance of the arch piece (121).

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