Underground centralizing type anode anti-corrosion tool

Abstract

The utility model provides an underground centering type anode anti-corrosion tool. The underground centering type anode anti-corrosion tool comprises an inner pipe, an insulating sleeve and an anode centralizer casting, the anode centralizer casting comprises a metal cylindrical base material and a plurality of metal anode blocks. The metal cylindrical base material is slidably sleeved on the outer surface of the insulating sleeve, a plurality of grooves are uniformly formed in the circumference of the surface of the metal cylindrical base material, and every two adjacent grooves are parallel to each other; the multiple grooves are fixedly filled with the multiple metal anode blocks in a one-to-one correspondence mode, and the metal mobility of the metal anode block materials is larger than that of the metal barrel-shaped base material. The centralizing anode integrated device and an oil pipe are placed in an underground casing pipe, casing pipe current is conducted to the replacement corrosion anode block through the metal cylindrical base material, the anode block material is preferentially sacrificed, and therefore the purpose of protecting the underground casing pipe is achieved. In addition, the size of the cross section of the largest anode block is small enough, when the device falls in the vertical state, the size of falling residues is smaller than the size of a gap between an oil pipe and a sleeve, and well jamming is prevented.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of oil exploitation, and particularly relates to a downhole centralizing anode anticorrosion tool. BACKGROUND

[0002] The traditional anode replacement corrosion device is mainly composed of a central pipe, a locking positioning assembly, an insulating assembly, a spring contact arm and the like.

[0003] In actual use, if the centralizer is not installed, the anode tool will be eccentrically ground with the casing, leading to the breakage of the elastic contact arm, the falling of the anode block and the like. Generally, a hard rubber centralizer is sleeved on one end of the central pipe of the anode tool. During the lifting and lowering of the well, the centralizer is continuously impacted with the locking positioning assembly of the anode tool during the up-and-down movement, which will cause the loosening of the anode module and the elastic contact arm, leading to poor contact and affecting the use effect and service life of the tool. The traditional anode block is a tubular cast part. If the anode block is cracked and falls into the gap between the tubing and the casing, the tubing will be stuck, leading to the difficulty in lifting the well during the well site maintenance.

[0004] Therefore, there is an urgent need for a device to solve the above problems in the prior art. SUMMARY

[0005] The main purpose of the utility model is to provide a downhole centralizing anode anticorrosion tool to at least solve the problem of anode module cracking and well sticking in the prior art.

[0006] In order to achieve the above purpose, the utility model provides a downhole centralizing anode anticorrosion tool, which comprises an inner pipe, an insulating sleeve and an anode centralizer casting. The inner pipe is used for oil transportation. The insulating sleeve is fixedly sleeved on the outer surface of the inner pipe. The anode centralizer casting comprises a metal cylindrical base material and a plurality of metal anode blocks. The metal cylindrical base material is slidably sleeved on the outer surface of the insulating sleeve. A plurality of grooves are uniformly arranged on the surface of the metal cylindrical base material, and adjacent two grooves are parallel to each other. A plurality of metal anode blocks are fixedly filled in the grooves one by one, and the metal activity of the metal anode block material is greater than that of the metal cylindrical base material.

[0007] Optionally, the metal cylindrical base material comprises two large-diameter ends and two small-diameter ends. The grooves extend from the end face of one large-diameter end of the metal cylindrical base material to the end face of the other large-diameter end. The two large-diameter ends are located between the two small-diameter ends.

[0008] Optionally, the righting anode integrated device further comprises two couplings and two insulation sleeve pads; the two couplings are respectively fixedly sleeved on the two ends of the inner pipe and tightly fit the outer surface of the inner pipe, and the couplings are used for connecting the oil pipe; the two insulation sleeve pads are respectively sleeved on the two ends of the anode centralizer casting, and each insulation sleeve pad is located between the coupling and the metal cylindrical base material; the inner surface of the first end of the insulation sleeve pad clearance fits the outer surface of the insulation sleeve, and the inner surface of the second end surface of the insulation sleeve pad threadedly fixedly fits the outer surface of the small-diameter end;

[0009] The two insulation sleeve pads are used for preventing the anode centralizer casting from contacting the two couplings when the anode centralizer casting moves axially along the inner pipe.

[0010] Optionally, the metal anode block is formed by pouring and filling the anode block material into the groove and then cooling.

[0011] Optionally, the groove is a dovetail groove.

[0012] Optionally, the shape of the metal anode block matches the shape of the groove.

[0013] The radial height of the metal anode block is less than the radial height of the groove in the radial direction from the central axis of the anode centralizer casting to the outer surface of the anode centralizer casting.

[0014] Optionally, the groove extends in a spiral shape from the first end of the metal cylindrical base material to the second end of the metal cylindrical base material.

[0015] The utility model discloses a kind of downhole anode anticorrosion tools of righting, including inner pipe, insulation sleeve and anode centralizer casting;Inner pipe is used for oil transport;Insulation sleeve is fixedly sleeved on the outer surface of inner pipe;Anode centralizer casting includes metal cylindrical base material and multiple metal anode blocks;Metal cylindrical base material is slidably sleeved on the outer surface of insulation sleeve, and the surface of metal cylindrical base material is evenly distributed with multiple grooves, and two adjacent grooves are parallel to each other;Multiple metal anode blocks are fixedly filled in multiple grooves one by one, and the metal activity of metal anode block material is greater than the metal activity of metal cylindrical base material material.Thereby, righting anode integrated device is placed in casing with oil pipe in well, when casing material produces electrochemical corrosion in corrosive medium environment, casing current is conducted to alternative corrosion anode block through metal cylindrical base material, anode block does not directly contact with casing, and anode block material is preferentially sacrificed, so as to achieve the purpose of protecting downhole casing.The cross-sectional dimension of the largest anode block is small enough, when the device falls in vertical state, the volume of the falling residue is less than the gap between oil pipe and casing, and the occurrence of well blocking can be reduced with high probability. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0017] Figure 1 This is a schematic diagram of an optional downhole anode corrosion protection tool according to an embodiment of the present utility model;

[0018] Figure 2 This is a schematic diagram of a cross-section of an anode centralizer casting, which is an optional embodiment of this utility model.

[0019] Figure 3 This is a schematic diagram of an optional anode centralizer casting according to an embodiment of the present utility model.

[0020] The above figures include the following reference numerals:

[0021] 10. Inner tube; 20. Insulating sleeve; 30. Anode centralizer casting; 31. Metal cylindrical substrate; 32. Metal anode block; 40. Coupling; 50. Insulating gasket. Detailed Implementation

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] like Figure 1 As shown, a downhole centralizer anode corrosion protection tool includes an inner tube 10, an insulating sleeve 20, and an anode centralizer casting 30. The inner tube 10 is used for oil transportation. The insulating sleeve 20 is fixedly fitted onto the outer surface of the inner tube 10. The anode centralizer casting 30 includes a metal cylindrical substrate 31 and multiple metal anode blocks 32. The metal cylindrical substrate 31 is slidably fitted onto the outer surface of the insulating sleeve 20. Multiple grooves are evenly distributed around the circumference of the surface of the metal cylindrical substrate 31, with adjacent grooves being parallel to each other. Multiple metal anode blocks 32 are fixedly filled into the multiple grooves one-to-one. The metal mobility of the metal anode block 32 material is greater than that of the metal cylindrical substrate 31 material.

[0024] Specifically, the integrated device for centralizing and anode includes three parts: an inner tube 10, an insulating sleeve 20, and an anode centralizer casting 30. The inner tube 10 is connected with the oil tube in the field and is used for transporting oil. The material of the inner tube 10 is usually corrosion-resistant alloy steel or stainless steel, which ensures long-term stable operation in the oil field environment. The insulating sleeve 20 is fixedly sleeved on the outer surface of the inner tube 10 to isolate the electrical connection between the inner tube 10 and the anode centralizer casting 30. The sleeve current is conducted to the alternative corrosion metal anode block 32 through the metal cylindrical base material 31, and the metal anode block 32 does not directly contact the inner tube 10.

[0025] In the anode centralizer casting 30, the metal cylindrical base material 31 acts as the oil tube centralizer in the prior art, and the metal anode block 32 acts as the alternative corrosion anode module in the prior art. In this application, the oil tube centralizer is closely combined with the alternative corrosion anode module. The metal cylindrical base material 31 in the anode centralizer casting 30 is sleeved on the outer surface of the insulating sleeve 20, and the material of the metal cylindrical base material 31 is usually selected from high-strength, corrosion-resistant alloy steel or stainless steel. A plurality of grooves are uniformly distributed on the surface of the metal cylindrical base material 31, and the grooves extend from the upper end to the lower end of the metal cylindrical base material 31. The grooves are used to provide sufficient space to fix the metal anode block 32. The metal anode block 32 is fixedly filled in the groove, and as the main component of corrosion protection, the metal activity of the material of the metal anode block 32 is greater than that of the material of the metal cylindrical base material 31, so as to ensure that the metal anode block 32 is preferentially corroded under the corrosion of the corrosion medium in the wellbore, thereby protecting the casing from damage. The material of the metal anode block 32 is usually a reactive metal such as magnesium-aluminum or an alloy thereof. The integrated device for centralizing and anode is placed in the casing in the wellbore with the oil tube. When the casing material produces electrochemical corrosion in the corrosive medium environment, the sleeve current is conducted to the alternative corrosion metal anode block 32 through the metal cylindrical base material 31, the metal anode block 32 does not directly contact the casing, and the metal anode block 32 is preferentially sacrificed, thereby achieving the purpose of protecting the casing in the wellbore. When the pipeline is put down, the anode centralizer casting 30 slides up and down outside the insulating sleeve 20 to centralize the oil tube. The size of the groove is consistent, so that the cross-sectional size of the largest metal anode block 32 is small enough. When the device falls in the vertical state, the volume of the falling residue is smaller than the gap between the oil tube and the casing, thereby preventing the well from being stuck.

[0026] In one possible implementation, the metal cylindrical base material 31 includes two large-diameter ends and two small-diameter ends; the grooves extend from the end face of one large-diameter end of the metal cylindrical base material 31 to the end face of the other large-diameter end; and the two large-diameter ends are located between the two small-diameter ends.

[0027] Specifically, the two end faces of the metal cylindrical base material 31 are stepped, and the outwardly protruding small-diameter end facilitates the connection of other structures. The small-diameter section is arranged such that, after the metal cylindrical base material 31 is connected with other structures, the maximum diameter can not exceed the diameter of the large-diameter end, so as to ensure that the maximum diameter of the centralizer-anode integrated device is the diameter of the large-diameter end.

[0028] In a possible implementation, the centralizer-anode integrated device further comprises two couplings 40 and two insulating sleeve pads 50. The two couplings 40 are respectively fixedly sleeved on the two ends of the inner pipe 10 through threads and tightly fit the outer surface of the inner pipe 10. The couplings 40 are used for connecting the oil pipe. The two insulating sleeve pads 50 are respectively sleeved on the two ends of the anode centralizer casting 30, and each insulating sleeve pad 50 is located between the coupling 40 and the metal cylindrical base material 31. The inner surface of the first end of the insulating sleeve pad 50 is gap-fitted with the outer surface of the insulating sleeve 20, and the inner surface of the second end face of the insulating sleeve pad 50 is threadedly fixed with the outer surface of the small-diameter end. The two insulating sleeve pads 50 are used to prevent the anode centralizer casting 30 from contacting the two couplings 40 respectively when the anode centralizer casting 30 moves axially along the inner pipe 10.

[0029] Specifically, a gap is left between the upper and lower ends of the anode centralizer casting 30 and the couplings 40. During the process of lifting and lowering the anode, the anode centralizer casting 30 gradually moves up and down outside the insulating pipe, and the gap ensures the movement range of the anode centralizer casting 30. The two ends of the anode centralizer casting 30 are respectively connected with the insulating sleeve pads 50. When the pipe is lifted and lowered, the anode centralizer casting 30 and the two insulating sleeve pads 50 slide up and down outside the insulating sleeve 20. The insulating sleeve pads 50 at the two ends of the anode centralizer casting 30 effectively isolate the contact between the anode centralizer casting 30 and the couplings 40, and ensure that the sleeve current can be transmitted to the metal anode block 32 during the anode replacement corrosion process, thereby protecting the couplings 40. In addition, the insulating sleeve pads 50 are rubber pads. During the up-and-down movement, the rubber pads act as a buffer to prevent the anode centralizer casting 30 from directly impacting the couplings 40 fixed to the oil pipe, so that the couplings 40 are not impacted and vibrated, causing the threads to loosen.

[0030] In a possible implementation, the metal anode block 32 is formed by pouring the anode block material into the groove and cooling.

[0031] Specifically, the metal anode block 32 is filled in the groove by pouring, and after cooling, it can tightly fit the groove surface of the metal cylindrical base material 31, forming a firm connection and improving the bonding strength between the metal anode block 32 and the metal cylindrical base material 31. In the event of electrochemical corrosion, it ensures smooth transmission of the sleeve current between the metal anode block 32 and the metal cylindrical base material 31, thereby improving the corrosion protection effect.

[0032] In a possible implementation, the groove is a dovetail groove.

[0033] Specifically, as shown in Figure 2 the groove cross-section is in the form of a dovetail groove, whose width gradually decreases from the position close to the center of the metal cylindrical base material 31 to the outward radial direction, and then gradually increases again. The dovetail groove shape enables the metal anode block 32 to form a more secure locking effect in the groove after filling and solidification. Compared with ordinary straight grooves or V-shaped grooves, the dovetail groove has greater locking force, which can effectively prevent the metal anode block 32 from loosening or falling off due to vibration or impact during long-term use. In addition, the bevel design of the dovetail groove cross-section increases the contact area between the metal anode block 32 and the metal cylindrical base material 31, and forms a more complex contact interface, thereby improving the friction between the metal anode block 32 and the base material and enhancing the shear resistance of the metal anode block 32 and the metal cylindrical base material 31.

[0034] The anode centralizer casting 30 is a one-piece casting. After the metal cylindrical base material 31 is partially cast, the anode metal melt is poured into the dovetail groove reserved in the metal cylindrical base material 31, and the metal cylindrical base material 31 and the metal anode block 32 are tightly combined by casting.

[0035] In one possible implementation, the shape of the metal anode block 32 matches the shape of the groove; wherein, in the radial direction from the central axis of the anode centralizer casting 30 to the outer surface of the anode centralizer casting 30, the radial height of the metal anode block 32 is less than the radial height of the groove.

[0036] Specifically, the close match between the metal anode block 32 and the groove ensures that the metal anode block 32 can be securely installed in the groove and is not prone to loosening or falling off, thereby improving the connection strength between the metal anode block 32 and the anode centralizer casting 30. The radial height of the metal anode block 32 is less than the radial height of the groove, i.e., the metal anode block 32 does not protrude above the surface of the metal cylindrical base material 31, which can reduce the friction between the anode centralizer casting 30 and the inner wall of the casing during up-and-down movement.

[0037] In one possible implementation, the groove extends in a spiral shape from the first end of the metal cylindrical base material 31 to the second end of the metal cylindrical base material 31.

[0038] Specifically, as shown in Figure 3 the design of the spiral groove provides an asymmetric and continuous rotational guide surface for the anode centralizer casting 30. During the up-and-down movement in the well, due to the action of gravity and fluid force, the spiral groove on the anode centralizer casting 30 will come into contact with the well wall or the inner wall of the pipeline when it moves in the well. Due to the shape and distribution of the groove, this contact will generate a rotational force, causing the anode centralizer casting 30 to rotate on the surface of the insulating casing 20. The outer surface of the anode centralizer casting 30 can be subjected to uniform frictional force, preventing eccentric wear.

[0039] The preferred embodiments of the present application have been described above with the preferred embodiments, but are not intended to limit the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A downhole anode corrosion protection tool, characterized in that, include: Inner tube, used for oil transportation; An insulating sleeve is fixedly fitted onto the outer surface of the inner tube; Anode centralizer castings, including: A metal cylindrical substrate is slidably fitted onto the outer surface of the insulating sleeve. Multiple grooves are evenly distributed around the circumference of the surface of the metal cylindrical substrate, with two adjacent grooves being parallel to each other. Multiple metal anode blocks are fixedly filled in multiple grooves in a one-to-one correspondence. The metal mobility of the metal anode block material is greater than that of the metal cylindrical substrate material.

2. The downhole anode corrosion protection tool according to claim 1, characterized in that, The metal cylindrical substrate includes: Two large-diameter ends, the groove extending from the end face of one of the large-diameter ends of the metal cylindrical substrate to the end face of the other large-diameter end; Two small-diameter ends, with the two large-diameter ends located between the two small-diameter ends.

3. The downhole anode corrosion protection tool according to claim 2, characterized in that, Also includes: Two couplings are respectively threaded and fitted onto both ends of the inner tube, and are tightly fitted to the outer surface of the inner tube. The couplings are used to connect to the oil pipe. Two insulating sleeves are respectively fitted onto both ends of the anode centralizer casting, and each insulating sleeve is located between the coupling and the metal cylindrical substrate; the inner surface of the first end of the insulating sleeve is clearance-fitted with the outer surface of the insulating sleeve, and the inner surface of the second end of the insulating sleeve is fixedly fitted with the outer surface of the small diameter end by threads; The two insulating gaskets are used to prevent the anode centralizer casting from contacting the two couplings respectively when the anode centralizer casting moves axially along the inner tube.

4. The downhole anode corrosion protection tool according to claim 1, characterized in that, The metal anode block is formed by casting the anode block material, filling it in the groove, and then cooling it.

5. The downhole anode corrosion protection tool according to claim 1, characterized in that, The groove is a dovetail groove.

6. The downhole anode corrosion protection tool according to claim 5, characterized in that, The shape of the metal anode block matches the shape of the groove; Wherein, in the radial direction from the central axis of the anode centralizer casting to the outer surface of the anode centralizer casting, the radial height of the metal anode block is less than the radial height of the groove.

7. The downhole anode corrosion protection tool according to claim 1, characterized in that, The groove extends in a spiral shape from the first end of the metal cylindrical substrate to the second end of the metal cylindrical substrate.

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