Oil casing pipe with sacrificial anode anti-corrosion function

Abstract

The utility model belongs to the technical field of oil exploitation, and particularly relates to an oil casing with a sacrificial anode anti-corrosion function. Comprising a sleeve, a sleeve coupling and an alloy anode structure, the sleeve coupling is arranged at one end of the sleeve, the sleeve coupling is in threaded connection with the sleeve, the alloy anode structure is connected to the sleeve through interference fit and hot charging, the alloy anode structure is in cold pressing connection with the sleeve, and an annular groove is formed in the inner side of the alloy anode structure. The alloy anode structure is arranged outside the sleeve to restrain metal electron migration on the surface of the sleeve, the alloy anode structure is in interference fit with the sleeve after being heated, the annular groove is formed in the inner side of the sleeve to better reach a preset position after being heated, radial binding force is reduced, and the service life of the sleeve is prolonged. After the alloy anode structure is cooled, the alloy anode structure and the oil pipe are fixed in a cold pressing mode, the corrosion effect can be guaranteed on the premise that the strength of the oil pipe is not damaged, the structure is simple, and the alloy anode structure can play a certain supporting role in strengthening cement.

Description

Technical Field

[0001] This utility model belongs to the field of petroleum extraction technology, and in particular to an oil casing with sacrificial anode anti-corrosion function. Background Technology

[0002] In oilfield development, corrosion damage to oil casing and tubing by well fluid, formation water, and seawater is common. This is due to electrochemical corrosion that occurs when steel oil casing and tubing come into contact with these substances. During the electrochemical reaction, the oil casing and tubing act as the anode of the battery, and the formation as the cathode. Iron ions from the oil casing and tubing continuously flow towards the formation, causing corrosion damage and affecting safe production in the oilfield. To inhibit electron migration on the surface of the oil casing and tubing, sacrificial anode cathodic protection technology is often used. Current sacrificial anode cathodic protection technology often involves connecting block or ring-shaped anode materials to the casing surface through welding or sleeve connections. However, welding the anode material can negatively impact the casing's strength and reduce its corrosion protection effect. While sleeve connections ensure a tight fit between the anode material and the casing, the block or ring-shaped anode material is difficult to fit snugly onto the casing during installation, causing some compression damage and resulting in severe corrosion damage. Utility Model Content

[0003] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide an oil casing with sacrificial anode anti-corrosion function, which reduces damage to the casing by utilizing its own structural characteristics and ensures the anti-corrosion effect.

[0004] The technical solution adopted by this utility model to solve its technical problem is as follows: the oil casing with sacrificial anode anti-corrosion function includes a casing, a casing coupling and an alloy anode structure. The casing coupling is set at one end of the casing and is threadedly connected to the casing. The alloy anode structure is heat-fitted onto the casing by interference fit and is cold-pressed to the casing. A circumferential groove is provided on the inner side of the alloy anode structure.

[0005] Preferably, at least two circumferential grooves are provided.

[0006] Preferably, the alloy anode structure has an outer conical surface at one end and an inner conical surface at the other end.

[0007] Preferably, the alloy anode structure is interference-fitted with the sleeve coupling.

[0008] Preferably, at least two alloy anode structures are provided.

[0009] Preferably, each circumferential groove has a conical surface at one end near the outer conical surface, and the diameter of the conical surface gradually decreases along the direction near the outer conical surface.

[0010] Compared with existing technologies, the beneficial effects of this technical solution are:

[0011] This invention suppresses electron migration of metal on the casing surface by setting an alloy anode structure on the outside of the casing. The alloy anode structure is pressurized with the casing after heating. In order to better reach the predetermined position after heating, an circumferential groove is set on the inside of the casing to reduce radial binding force. After the alloy anode structure cools, the two are cold-pressed to fix them. This can ensure the anti-corrosion effect without damaging the strength of the oil pipe. The structure is simple, and the alloy anode structure can also provide a certain support for the straightening cement, thus playing a role in straightening the casing. Attached Figure Description

[0012] Figure 1 This is a cross-sectional view of an oil casing pipe with sacrificial anode anti-corrosion function according to the present invention.

[0013] Figure 2 This is a cross-sectional view of the alloy anode structure of this utility model.

[0014] Among them: 1. Sleeve 2. Alloy anode structure 201. Circumferential groove 202. Outer conical surface 203. Inner conical surface 3. Sleeve coupling. Detailed Implementation

[0015] Figures 1-2 This is the preferred embodiment of the present invention, which is described below in conjunction with the appendix. Figures 1-2 The present invention will be further described below.

[0016] Reference Figure 1 The oil casing with sacrificial anode corrosion protection function includes a casing 1, a casing coupling 3, and an alloy anode structure 2. Both ends of the casing 1 are provided with external threads, and the casing coupling 3 is provided with internal threads and is threaded to one end of the casing 1. The alloy anode structure 2 is a tubular structure of magnesium-aluminum alloy and is connected to the casing 1 with an interference fit. The alloy anode structure 2 is heated and fitted onto the corresponding position of the casing 1. After cooling, the alloy anode structure 2 is radially rolled using a tool. The inner side of the alloy anode structure 2 is provided with an circumferential groove 201.

[0017] In this invention, five circumferential grooves 201 are arranged according to the length of the alloy anode structure 2, and are equidistantly arranged on the inner side of the alloy anode structure 2. The alloy anode structure 2 inhibits the migration of metal electrons on the surface of the sleeve 1. Multiple alloy anode structures 2 need to be inserted into the sleeve 1 from the end without the sleeve coupling 3, and then installed in different positions. The distance they travel during installation is different. In order to ensure a stable connection between the alloy anode structure 2 and the sleeve 1, the anode alloy structure 2 and the sleeve 1 are interference-fitted, which causes certain difficulties during installation. In order to better reach the predetermined position after heating, circumferential grooves 201 are provided on the inner side of the alloy anode structure 2, and each circumferential groove 201 has a conical surface at the end near the outer conical surface 202. The diameter of the conical surface gradually decreases along the direction near the outer conical surface 202, thereby reducing the radial binding force and facilitating the insertion of the sleeve 1 into the alloy anode structure 2. After the alloy anode structure 2 is cooled, the alloy anode structure 2 and the sleeve 1 are fixed by cold pressing or roll pressing; at the same time, the circumferential groove 201 and the sleeve 1 form an anchoring effect, which is beneficial to the fixation between the circumferential groove 201 and the sleeve 1.

[0018] According to the length of the sleeve 1, alloy anode structures 2 are set at corresponding positions. At least two alloy anode structures 2 are set. The outer surface of the sleeve 1 is polished and rusted in the area corresponding to the installation position of the alloy anode structure 2. The polishing and rust removal length is greater than the installation length of the alloy anode structure 2. The alloy anode structure 2 is heated to 300±20℃. The end with the inner conical surface 203 is aligned with the end of the sleeve 1 that is not fitted with the sleeve coupling 3 and inserted. The inner conical surface 203 is set to facilitate alignment with the sleeve 1. Multiple alloy anode structures 2 are sequentially moved to the predetermined positions. After the alloy anode structure 2 cools to room temperature, the alloy anode structure 2 is radially rolled using a tool to complete the installation of the alloy anode structure 2 and the sleeve 1.

[0019] After the alloy anode structure 2 is installed, the casing 1 is connected to the casing 1 via the casing coupling 3 to form an oil casing. The other end of the alloy anode structure 2 has an outer conical surface 202 to facilitate the insertion of the oil casing into the oil and gas well and reduce collisions with the alloy anode structure 2. The diameter of the alloy anode structure 2 is less than or equal to the diameter of the casing coupling 3, which helps to straighten the casing 1 during casing running and downhole operations, improving the casing's centering in the wellbore and contributing to better uniformity and cementing quality.

[0020] Work process:

[0021] On the outer surface of the sleeve 1, the area corresponding to the installation of the alloy anode structure 2 is polished and rusted. The alloy anode structure 2 is heated to 300±20℃, and the end with the inner conical surface 203 is aligned with the end of the sleeve 1 without the sleeve coupling 3 and inserted. Multiple alloy anode structures 2 are sequentially moved to the predetermined position. After the alloy anode structure 2 cools to room temperature, the alloy anode structure 2 is radially rolled using a tool to complete the installation of the alloy anode structure 2 and the sleeve 1. The sleeve coupling 3 is installed on one end of the sleeve 1, and the installation position is opposite to the outer conical surface 202 of the alloy anode structure 2. Then it is connected to another sleeve 1 with the alloy anode structure 2 installed through the sleeve coupling 3. The sleeves are connected sequentially according to the actual required oil sleeve length.

[0022] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model without departing from its technical solution shall still fall within the protection scope of this utility model.

Claims

1. A tubing-casing with sacrificial anode anticorrosion function, characterized in that: The alloy anode structure (2) is connected on the casing (1) through interference fit and is cold-pressed with the casing (1), and the inner side of the alloy anode structure (2) is provided with a ring groove (201).

2. The oil casing with the sacrificial anode anti-corrosion function according to claim 1, characterized in that: The ring groove (201) is provided with at least two.

3. The oil casing with the sacrificial anode anti-corrosion function according to claim 1, characterized in that: The alloy anode structure (2) is provided with an outer taper surface (202) at one end and an inner taper surface (203) at the other end.

4. The oil casing with the sacrificial anode anti-corrosion function according to claim 3, characterized in that: Each ring groove (201) is provided with a taper surface at one end close to the outer taper surface (202), and the diameter of the taper surface gradually decreases in the direction close to the outer taper surface (202).

5. The oil casing with the sacrificial anode anti-corrosion function according to claim 1, characterized in that: The alloy anode structure (2) is connected with the casing collar (3) through interference fit.

6. The oil casing with the sacrificial anode anti-corrosion function according to claim 1, characterized in that: The alloy anode structure (2) is provided with at least two.

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