Casing pipe anti-corrosion tool and casing pipe system

Abstract

The invention belongs to the technical field of petroleum, and discloses a casing pipe anti-corrosion tool and a casing pipe system.The casing pipe anti-corrosion tool comprises an anti-corrosion cylinder, fixing assemblies and a protective cylinder, the anti-corrosion cylinder is arranged on the outer side of a casing pipe body in a sleeving mode, and the two ends of the anti-corrosion cylinder are each provided with one fixing assembly. The fixing assembly comprises a pressing ring and a fixing piece, the pressing ring abuts against the anti-corrosion cylinder and the sleeve body, and the fixing piece penetrates through the pressing ring and the anti-corrosion cylinder and is screwed on the sleeve body. The protective cylinder sleeves the anti-corrosion cylinder, an annular space is defined by the protective cylinder and the anti-corrosion cylinder, a plurality of through holes are formed in the protective cylinder, and corrosive fluid enters the annular space through the through holes to form a conductive loop. The anti-corrosion cylinder is made of sacrificial anode materials, a primary battery is formed through the potential difference between the anti-corrosion cylinder and the sleeve body, the anti-corrosion cylinder serves as an anode to conduct dissolution corrosion, the sleeve body serves as a cathode to be protected, the sleeve body is prevented from being corroded, and the service life of the sleeve body is prolonged. And the protection barrel can prevent the anti-corrosion barrel from being rubbed with rock of the well wall to affect the protection effect, and the protection effect is achieved.

Description

Technical Field

[0001] This invention relates to the field of petroleum technology, and in particular to a casing corrosion protection tool and casing system. Background Technology

[0002] Wellbore corrosion is a serious problem that persists throughout the wellbore's lifespan, directly impacting the integrity, production safety, and economic benefits of oil and gas wells. In the high-temperature, acidic, and microbial environment of the bottom-hole fluid, the primary corrosion occurring in the casing is electrochemical corrosion, where steel acts as the anode and dissolves. This easily leads to thinning and even perforation of the casing. On one hand, it causes the casing to lose its protective function against the wellbore fluid and the external formation; on the other hand, it increases the need for subsequent production or workover string installation, affecting production, increasing wellbore repair costs, and even leading to well shutdown and abandonment.

[0003] Currently, common corrosion protection technologies include anti-corrosion coatings or chemical methods using corrosion inhibitors. However, coatings are inevitably scratched during well entry, creating cathodic and anodic zones at the damaged areas, which are prone to localized electrochemical corrosion, shortening the coating's service life. Corrosion inhibitors can effectively alter the solubility and composition of the downhole fluid electrolyte, thereby inhibiting corrosion. However, these agents are primarily used for corrosion control inside the wellbore and cannot alleviate casing corrosion on the outside. Summary of the Invention

[0004] The purpose of this invention is to provide a casing corrosion protection tool and casing system. This corrosion protection tool can effectively slow down the corrosion rate of the outer wall of the casing body and extend the service life of the casing body.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] On the one hand, a casing corrosion protection tool is provided, including:

[0007] A corrosion-resistant sleeve is fitted onto the outside of the sleeve body, and the corrosion-resistant sleeve is made of sacrificial anode material;

[0008] The fixing components are provided at both ends of the anti-corrosion cylinder. Each fixing component includes a pressure ring and a fixing member. The pressure ring abuts against the anti-corrosion cylinder and the sleeve body. The fixing member passes through the pressure ring and the anti-corrosion cylinder in sequence and is screwed onto the sleeve body.

[0009] A protective sleeve is fitted over the outside of the anti-corrosion sleeve. The protective sleeve has multiple through holes spaced apart. An annular space is formed between the protective sleeve and the anti-corrosion sleeve. Each through hole is connected to the annular space, allowing corrosive fluid from the outside of the sleeve body to enter the annular space through the through holes.

[0010] As an optional solution for the casing corrosion protection tool, the fixing component further includes a first sealing element and a second sealing element spaced apart on both sides of the fixing element. The first sealing element is disposed between the pressure ring and the casing body, and the second sealing element is disposed between the pressure ring and the corrosion protection cylinder.

[0011] As an optional solution for casing corrosion protection tools, the fastener is made of a corrosion-resistant and conductive material.

[0012] As an optional solution for casing corrosion protection, the pressure ring is made of corrosion-resistant material.

[0013] As an optional solution for casing corrosion protection, the outer peripheral wall of the pressure ring is coated with an anti-corrosion layer.

[0014] As an optional solution for casing corrosion protection tools, a third sealing element is provided on the outside of the fixing element, which is used to seal the gap between the pressure ring and the fixing element.

[0015] As an optional solution for casing corrosion protection tools, the protective sleeve is made of corrosion-resistant material or is coated with an anti-corrosion layer.

[0016] As an optional solution for casing corrosion protection tools, the fixing element is a pin.

[0017] On the other hand, a casing system is provided, including the casing anti-corrosion tool described above and a plurality of casing bodies, wherein a joint is provided between two adjacent casing bodies.

[0018] As an optional solution for the casing system, the two ends of the connector are respectively threaded onto two adjacent casing bodies, and the threaded positions of the connector are plated with an anti-corrosion layer.

[0019] The beneficial effects of this invention are:

[0020] This invention provides a casing corrosion protection tool and casing system. The casing corrosion protection tool includes an anti-corrosion cylinder, a fixing component, and a protective cylinder. The anti-corrosion cylinder is sleeved on the outside of the casing body, and a fixing component is provided at both ends of the anti-corrosion cylinder. The fixing component includes a pressure ring and a fixing member. The pressure ring abuts against the anti-corrosion cylinder and the casing body, and the fixing member passes through the pressure ring and the anti-corrosion cylinder in sequence and is screwed onto the casing body to fix the anti-corrosion cylinder to the casing body. The protective cylinder is sleeved on the outside of the anti-corrosion cylinder. The protective cylinder has multiple through holes spaced apart, and an annular space is formed between the protective cylinder and the anti-corrosion cylinder. Each through hole is connected to the annular space, allowing corrosive fluid on the outside of the casing body to enter the annular space through the through holes to form a conductive circuit. The anti-corrosion cylinder is made of sacrificial anode material. A galvanic cell is formed by the potential difference between the anti-corrosion cylinder and the casing body. The anti-corrosion cylinder acts as the anode for dissolution corrosion, while the casing body acts as the cathode and is protected, preventing corrosion of the casing body and thus slowing down the corrosion rate on the outside of the casing body, extending the service life of the casing body. In addition, the protective casing can prevent the anti-corrosion casing from rubbing against the well wall rock during the process of lowering the casing body into the well, thus avoiding affecting the protective effect and playing a certain protective role for the anti-corrosion casing. Attached Figure Description

[0021] Figure 1 This is an overall schematic diagram of the casing corrosion protection tool provided in the specific embodiments of the present invention;

[0022] Figure 2 yes Figure 1 A magnified view of a portion of point A in the middle.

[0023] In the picture:

[0024] 100. Sleeve body; 200. Connector;

[0025] 1. Corrosion-resistant cylinder;

[0026] 2. Fixing components;

[0027] 21. Pressure ring; 22. Fixing element; 23. First sealing element; 24. Second sealing element; 25. Third sealing element;

[0028] 3. Protective sleeve; 31. Through hole;

[0029] 4. Circular space. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0031] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0033] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0034] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0035] like Figures 1 to 2As shown, this embodiment provides a casing corrosion protection tool, including a corrosion-resistant cylinder 1, a fixing component 2, and a protective cylinder 3. The corrosion-resistant cylinder 1 is sleeved on the outside of the casing body 100, and a fixing component 2 is provided at both ends of the corrosion-resistant cylinder 1. The fixing component 2 includes a pressure ring 21 and a fixing member 22. The pressure ring 21 abuts against the corrosion-resistant cylinder 1 and the casing body 100, and the fixing member 22 passes through the pressure ring 21 and the corrosion-resistant cylinder 1 in sequence and is screwed onto the casing body 100 to fix the corrosion-resistant cylinder 1 to the casing body 100. The protective cylinder 3 is sleeved on the outside of the corrosion-resistant cylinder 1, and multiple through holes 31 are spaced apart on the protective cylinder 3. An annular space 4 is formed between the protective cylinder 3 and the corrosion-resistant cylinder 1, and each through hole 31 is connected to the annular space 4. Corrosive fluid outside the casing body 100 can enter the annular space 4 through the through holes 31 to form a conductive circuit. The anti-corrosion sleeve 1 is made of sacrificial anode material. A galvanic cell is formed between the anti-corrosion sleeve 1 and the casing body 100, with the anti-corrosion sleeve 1 acting as the anode for dissolution corrosion, while the casing body 100 acts as the cathode and is protected, preventing corrosion of the casing body 100 and thus slowing down the corrosion rate on the outside of the casing body 100, extending its service life. Furthermore, the protective sleeve 3 prevents the anti-corrosion sleeve 1 from rubbing against the wellbore rock during the casing body's lowering process, thus protecting the anti-corrosion sleeve 1 to a certain extent.

[0036] Specifically, the sacrificial anode material used in the anti-corrosion casing 1 needs to be determined based on the external environment of the casing. If the external soil or formation water has high salinity and low resistivity, aluminum-based alloys or zinc-based alloys can be used to prevent rapid dissolution and corrosion of the anti-corrosion casing 1. If the external soil has low resistivity and weak conductivity, magnesium-based alloys with more negative potential and stronger activity can be used to increase the current intensity. In addition, the outer diameter of the protective casing 3 is comparable to the joint size of the casing body 100 to ensure the smooth lowering of the casing body into the well and avoid stuck pipe accidents.

[0037] Optionally, the pressure ring 21 is made of a corrosion-resistant material to prevent it from rapidly corroding and dissolving, thus losing its fixing and limiting function for the anti-corrosion cylinder 1. Specifically, the anti-corrosion material is one that has been disclosed in the prior art, and will not be described in detail here.

[0038] Furthermore, the outer peripheral wall of the pressure ring 21 is coated with an anti-corrosion layer to further slow down the corrosion rate of the pressure ring 21 and improve its corrosion resistance.

[0039] Specifically, the anti-corrosion layer is a coating that has been disclosed in the existing technology. Its specific composition is based on the existing technology, and it is sufficient as long as it can slow down the corrosion rate. It will not be described in detail here.

[0040] Optionally, the fastener 22 is made of a corrosion-resistant and conductive material. While fixing the anti-corrosion cylinder 1, it establishes a conductive connection between the anti-corrosion cylinder 1 and the sleeve body 100, thereby allowing electrons released by the sacrificial anode to be transferred to the sleeve body 100 in a low-resistance conductive environment, forming an effective protective current. Furthermore, the use of a corrosion-resistant material prevents the pin from corroding and dissolving prematurely and losing its conductivity.

[0041] For example, the fastener 22 is made of materials such as aluminum, copper or tin.

[0042] Optionally, the fastener 22 is a pin. The pressure ring 21 has a threaded hole, and the fastener 22 is screwed into the threaded hole. The anti-corrosion cylinder 1 only has a hole and does not need to be threaded. The sleeve body 100 does not have a hole. The anti-corrosion cylinder 1 is fixed by directly screwing the screw so that the tip of the screw enters the sleeve body 100, while minimizing the damage to the sleeve body 100.

[0043] Optionally, a third sealing element 25 is provided on the outside of the fixing frame. The third sealing element 25 is used to seal the gap between the pressure ring 21 and the fixing element 22 to prevent corrosive fluid from entering between the anti-corrosion cylinder 1 and the casing body 100 through the gap between the fixing element 22 and the pressure ring 21. This avoids the wall surface of the anti-corrosion cylinder 1 facing the casing body 100 from directly contacting the corrosive fluid, thus extending the service life of the anti-corrosion cylinder 1.

[0044] Specifically, the third sealing element 25 can be a sealant or a gasket, as long as it can isolate the fixing element 22 from the corrosive fluid on the outside. For example, in this embodiment, the gap between the outer side of the fixing element 22 and the pressure ring 21 is directly welded to achieve a sealing and isolation effect.

[0045] Optionally, the protective cylinder 3 is made of corrosion-resistant material or coated with an anti-corrosion layer. These features prevent corrosion of the protective cylinder 3 and ensure effective protection of the anti-corrosion cylinder 1.

[0046] Specifically, the anti-corrosion materials and anti-corrosion layers refer to existing technologies, and will not be described in detail here.

[0047] Optionally, the fixing assembly 2 further includes a first sealing element 23 and a second sealing element 24 spaced apart on both sides of the fixing member 22. The first sealing element 23 is disposed between the pressure ring 21 and the sleeve body 100 to seal the gap between the pressure ring 21 and the sleeve body 100; the second sealing element 24 is disposed between the pressure ring 21 and the anti-corrosion cylinder 1 to seal the gap between the pressure ring 21 and the anti-corrosion cylinder 1. While the anti-corrosion cylinder 1 acts as a sacrificial anode and forms a galvanic cell with the sleeve body 100 for protective corrosion, it also reacts with the corrosive fluid and corrodes itself. Under the sealing effect of the first sealing element 23 and the second sealing element 24, the contact area between the anti-corrosion cylinder 1 and the corrosive fluid can be effectively reduced, the corrosion rate caused by the anti-corrosion cylinder 1 directly contacting the corrosive fluid can be reduced, the dissolution cycle of the anti-corrosion cylinder 1 can be extended, and thus the protection time for the sleeve body 100 can be extended.

[0048] For example, in this embodiment, both the first seal 23 and the second seal 24 are annular sealing rings.

[0049] Specifically, the wall surface of the pressure ring 21 that contacts the anti-corrosion cylinder 1 is also coated with an anti-corrosion layer to prevent the anti-corrosion cylinder 1, which is close to the first seal 23 and the second seal 24, from dissolving due to direct contact with corrosive fluid, thus ensuring the sealing effect of the first seal 23 and the second seal 24.

[0050] In addition, this embodiment also provides a casing system, including the above-mentioned casing anti-corrosion tool and multiple casing bodies 100. A connector 200 is provided between two adjacent casing bodies 100 to connect the multiple casing bodies 100 together, so that the multiple casings form an effective conductive connection, thereby making the multiple casing bodies 100 all serve as cathodes and are protected against corrosion.

[0051] Optionally, the two ends of the connector 200 are respectively threaded onto two adjacent sleeve bodies 100. The threaded portion of the connector 200 is plated with an anti-corrosion layer to prevent corrosion due to long-term contact with corrosive fluids, thereby extending the service life of the connector 200 and ensuring the connection stability of the sleeve system. At the same time, it ensures that the two adjacent sleeve bodies 100 maintain an effective conductive connection.

[0052] Alternatively, the threaded portion of connector 200 can be nickel-plated or electroplated with other alloys to achieve corrosion protection at the threaded portion.

[0053] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A casing corrosion protection tool, characterized in that, include: The anti-corrosion sleeve (1) is sleeved on the outside of the sleeve body (100), and the anti-corrosion sleeve (1) is made of sacrificial anode material; Fixing component (2): Each end of the anti-corrosion cylinder (1) is provided with a fixing component (2). The fixing component (2) includes a pressure ring (21) and a fixing member (22). The pressure ring (21) abuts against the anti-corrosion cylinder (1) and the sleeve body (100). The fixing member (22) passes through the pressure ring (21) and the anti-corrosion cylinder (1) in sequence and is screwed onto the sleeve body (100). A protective sleeve (3) is fitted on the outside of the anti-corrosion sleeve (1). The protective sleeve (3) has multiple through holes (31) spaced apart. An annular space (4) is formed between the protective sleeve (3) and the anti-corrosion sleeve (1). Each through hole (31) is connected to the annular space (4). Corrosive fluid outside the sleeve body (100) can enter the annular space (4) through the through hole (31).

2. The casing corrosion protection tool according to claim 1, characterized in that, The fixing component (2) further includes a first sealing element (23) and a second sealing element (24) spaced apart on both sides of the fixing element (22). The first sealing element (23) is disposed between the pressure ring (21) and the sleeve body (100), and the second sealing element (24) is disposed between the pressure ring (21) and the anti-corrosion cylinder (1).

3. The casing corrosion protection tool according to claim 1, characterized in that, The fastener (22) is made of a corrosion-resistant and conductive material.

4. The casing corrosion protection tool according to claim 1, characterized in that, The pressure ring (21) is made of corrosion-resistant material.

5. The casing corrosion protection tool according to claim 4, characterized in that, The outer peripheral wall of the pressure ring (21) is coated with an anti-corrosion layer.

6. The casing corrosion protection tool according to any one of claims 1-5, characterized in that, A third sealing element (25) is provided on the outside of the fixing element (22), and the third sealing element (25) is used to seal the gap between the pressure ring (21) and the fixing element (22).

7. The casing corrosion protection tool according to any one of claims 1-5, characterized in that, The protective cylinder (3) is made of corrosion-resistant material or is coated with an anti-corrosion layer.

8. The casing corrosion protection tool according to any one of claims 1-5, characterized in that, The fastener (22) is a pin.

9. A casing system, characterized in that, The tool includes the casing corrosion protection tool as described in any one of claims 1-8 and a plurality of casing bodies (100), wherein a joint (200) is provided between two adjacent casing bodies (100).

10. The casing system according to claim 9, characterized in that, The two ends of the connector (200) are respectively threaded onto two adjacent sleeve bodies (100), and the threaded positions of the connector (200) are plated with an anti-corrosion layer.

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