Anti-corrosion protection device for oil-water well casing pipe

Abstract

The utility model discloses an oil-water well casing pipe anti-corrosion protection device which comprises an anti-corrosion assembly, a central pipe is sleeved with the anti-corrosion assembly, a long insulating bush is sleeved with a temperature-resistant sacrificial anode, a short insulating bush is sleeved with a guide cylinder, and a plurality of spring contact arms are evenly arranged in the circumferential direction of the guide cylinder. The two ends of the spring contact arm are located at the two ends of the guide cylinder in the length direction respectively, and any end of the spring contact arm is connected with the temperature-resistant sacrificial anode. The long insulating bush and the short insulating bush are sleeved on the central tube, so that the corrosion resistance and the wear resistance of the central tube are improved, the temperature-resistant sacrificial anode, the sleeve and an oil-water well environment form a primary battery, so that the temperature-resistant sacrificial anode continuously provides protection current for the sleeve, active metal on the temperature-resistant sacrificial anode is easy to lose electrons, and the service life of the sleeve is prolonged. And the metal (sleeve) which is corroded and dissolved preferentially and is inactive is used as a cathode and is subjected to cathode polarization reaction, so that the metal (sleeve) is protected, and the corrosion prevention effect on the sleeve is achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to oil and water well casing anticorrosion technical field especially relates to a kind of oil and water well casing anticorrosion protection device. BACKGROUND

[0002] In the development and production process of oil field, the corrosion problem faced by oil and water well is always the key restricting factor of hindering the efficient and stable exploitation of oil field. In recent years, with the continuous promotion of oil field water injection development work, many regions have entered the high water cut development stage. At this stage, the water quality of injected water and formation produced water contains a large amount of corrosive media such as dissolved oxygen, hydrogen sulfide and carbon dioxide. These corrosive media have strong chemical activity and can cause serious erosion to downhole tools in oil and water wells, such as casing, oil pump and packer. Especially the casing, as an important channel for oil well production, is prone to wall thinning, perforation and other phenomena under long-term corrosion, which leads to frequent casing loss failure.

[0003] The material-based corrosion prevention methods such as using corrosion-resistant casing and implementing corrosion prevention treatment on downhole tools are common. However, such methods face many challenges in practical application. On the one hand, due to the high cost of the corrosion-resistant materials used, the overall corrosion prevention measures are expensive; on the other hand, in terms of corrosion prevention effect, the performance is not satisfactory, and the casing still has different degrees of corrosion.

[0004] Therefore, the utility model is proposed to solve the above technical problems. UTILITY MODEL CONTENT

[0005] The utility model aims to provide a kind of oil and water well casing anticorrosion protection device to solve the technical problem of poor corrosion prevention effect of oil and water well casing in prior art.

[0006] The technical scheme of the utility model is: a kind of oil and water well casing anticorrosion protection device, including anticorrosion component, anticorrosion component is sleeved on center tube, anticorrosion component includes:

[0007] Long insulation bushing, long insulation bushing is sleeved on center tube;

[0008] Two short insulation pads, two short insulation pads are connected at the both ends of long insulation bushing respectively, and short insulation pad is sleeved on center tube;

[0009] Temperature-resistant sacrificial anode, temperature-resistant sacrificial anode is sleeved on long insulation bushing;

[0010] Short insulation bushing, short insulation bushing is sleeved on center tube;

[0011] Guide cylinder, guide cylinder is sleeved on short insulation bushing;

[0012] A plurality of spring contact arms are evenly arranged along the circumferential direction of the guide cylinder, and the two ends of the spring contact arms are located at the two ends of the length direction of the guide cylinder, and any end of the spring contact arm is connected with the temperature-resistant sacrificial anode.

[0013] The sleeve is sleeved on the temperature-resistant sacrificial anode, and the spring contact arm abuts against the inner wall of the sleeve.

[0014] Further, the two short insulation pads are provided with locking sleeves, the locking sleeves are sleeved on the corresponding short insulation pads, and a threaded locking cap is sleeved on the locking sleeve;

[0015] The guide cylinder is sleeved on the locking sleeve, and the locking cap fixes the one end of the guide cylinder when cooperating with the locking sleeve.

[0016] Further, a tightening nut is sleeved on the end of the guide cylinder away from the temperature-resistant sacrificial anode, and an external thread is arranged on the center pipe and matched with the tightening nut, and the tightening nut is used to fix the end of the guide cylinder away from the temperature-resistant sacrificial anode.

[0017] Further, an oil pipe coupling is arranged at any end of the center pipe, and the oil pipe coupling is used to connect an oil pipe.

[0018] Further, a polyethylene coating is coated on the outer circumferential wall of the center pipe.

[0019] By adopting the above technical scheme, the oil-water well casing anticorrosion protection device has the following beneficial effects:

[0020] In order to improve the corrosion and wear resistance of the center pipe, the long and short insulation bushings are sleeved on the center pipe. Meanwhile, the temperature-resistant sacrificial anode is arranged to form a primary battery system with the sleeve and the oil-water well environment. In the primary battery, the temperature-resistant sacrificial anode continuously supplies protection current to the sleeve. Because the active metal on the temperature-resistant sacrificial anode has strong electron loss ability, it will be oxidized as an anode and be preferentially corroded and dissolved. The relatively inactive sleeve acts as a cathode and undergoes cathodic polarization, thereby being protected and effectively preventing corrosion of the sleeve. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings are part of the present application and are used to provide a further understanding of the present application, and the schematic embodiments of the present application and the description thereof are used to explain the present application, but do not constitute an improper limitation on the present application. Obviously, the drawings described below are only some embodiments, and other drawings can be obtained by those skilled in the art without creative labor. In the drawings:

[0022] Figure 1 The structure of the oil-water well casing anticorrosion protection device provided in the present embodiment is shown in the accompanying drawings.

[0023] 1, central tube; 2, temperature-resistant sacrificial anode; 3, long insulating bushing; 4, short insulating pad; 5, locking sleeve; 6, locking cap; 7, oil pipe coupling; 8, short insulating bushing; 9, guide cylinder; 10, spring contact arm.

[0024] It should be noted that the drawings and the written description are not intended to limit the scope of the inventive concept in any way, but to illustrate the inventive concept to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0025] The specific embodiments of the present application will be further described in detail with reference to the accompanying drawings.

[0026] Referring to Figure 1 As shown in the drawings, the oil-water well casing anticorrosion protection device provided by the embodiments of the present application comprises an anticorrosion assembly, the anticorrosion assembly is sleeved on the central tube 1, and the anticorrosion assembly comprises a long insulating bushing 3, two short insulating pads 4, a temperature-resistant sacrificial anode 2, a short insulating bushing 8, a guide cylinder 9 and a plurality of spring contact arms 10. The long insulating bushing 3 is sleeved on the central tube 1, the two short insulating pads 4 are respectively connected at both ends of the long insulating bushing 3, and the short insulating pads 4 are sleeved on the central tube 1. The temperature-resistant sacrificial anode 2 is sleeved on the long insulating bushing 3, the short insulating bushing 8 is sleeved on the central tube 1, the guide cylinder 9 is sleeved on the short insulating bushing 8, and the plurality of spring contact arms 10 are uniformly arranged along the circumferential direction of the guide cylinder 9. The two ends of the spring contact arm 10 are respectively located at both ends of the length direction of the guide cylinder 9, and any end of the spring contact arm 10 is connected with the temperature-resistant sacrificial anode 2. In the anticorrosion assembly, the casing is sleeved on the temperature-resistant sacrificial anode 2, and the spring contact arm 10 abuts against the inner wall of the casing.

[0027] It should be noted that the long insulating bushing 3 and the short insulating bushing 8 are made of seamless insulating material (such as polyethylene seamless pipe or nylon seamless pipe) by integral molding; the temperature-resistant sacrificial anode 2 has a length of 900 mm, an outer diameter of 98 mm and an inner diameter of 78.5 mm; and the short insulating pad 4 is used to ensure that the temperature-resistant sacrificial anode 2 is insulated from the central tube 1 with an electrical resistance ≥500 MΩ (DC 500 V).

[0028] In the embodiments of the present application, the guide cylinder 9 is used in cooperation with the spring contact arm 10, and has the following effects:

[0029] 1. The guide cylinder 9 provides a precise guiding path for the extension, retraction, and movement of the spring contact arm 10, ensuring that the spring contact arm 10 can accurately contact the sleeve along a specific direction. During the process of the sleeve corrosion protection device provided in this embodiment being lowered into the sleeve, the guide cylinder 9 can guide the spring contact arm 10 smoothly through the bending and diameter change parts of the sleeve, preventing the spring contact arm 10 from deviating or getting stuck, ensuring that it can accurately reach the predetermined position and play its role, thereby achieving effective corrosion protection for the sleeve; the surface of the heat-resistant sacrificial anode 2 shall not have defects such as pores, sand holes, burrs, and cracks.

[0030] 2. The working environment inside the casing is complex, with various impurities, fluid erosion, and mechanical friction. The guide cylinder 9 provides physical protection for the spring contact arm 10, reducing direct friction and collision between the spring contact arm 10 and the inner wall of the casing, preventing damage to the spring contact arm 10 due to excessive wear, compression, or impact, extending the service life of the spring contact arm 10, and thus ensuring the long-term stable operation of the anti-corrosion protection device.

[0031] 3. The spring contact arm 10 needs to maintain a certain degree of elasticity and extensibility during operation to adapt to the deformation of the bushing and changes in working conditions. The guide cylinder 9 can limit the range of motion of the spring contact arm 10, allowing it to work within a reasonable range of elastic deformation, preventing the spring contact arm 10 from over-extending or compressing, thereby ensuring that the spring contact arm 10 can always maintain a good working condition, stably contact the bushing, and provide reliable anti-corrosion protection.

[0032] In the above scheme, by installing long insulating bushings 3 and short insulating bushings 8 on the central pipe 1, the corrosion resistance and wear resistance of the central pipe 1 are improved. The set high-temperature sacrificial anode 2 forms a galvanic cell with the casing and the oil and water well environment, so that the high-temperature sacrificial anode 2 continuously provides protective current to the casing. The active metal on the high-temperature sacrificial anode 2 easily loses electrons and undergoes an oxidation reaction as the anode, and is preferentially corroded and dissolved. The inactive metal (casing) acts as the cathode and undergoes a cathodic polarization reaction, thereby being protected and playing a role in protecting the casing from corrosion.

[0033]

[0034] Table 1

[0035] Table 1 shows the chemical composition (Wt%) of the heat-resistant sacrificial anode 2 in an oil-water well environment at 45-80℃.

[0036] Based on the actual operating conditions of oil and water wells, the evaluation temperature for the electrochemical performance of the heat-resistant sacrificial anode 2 was determined to be 70℃, and the salinity was determined to be 50g / L (see Table 2 for specific components).

[0037]

[0038] Table 2 simulated formation water composition (mg / L)

[0039] In the working condition of 70 DEG C and 50g / L salinity, the electrochemical performance of the temperature-resistant sacrificial anode 2 meets the requirements of Table 3.

[0040]

[0041] Table 3 electrochemical performance of temperature-resistant sacrificial anode 2

[0042] In some possible embodiments, referring to Fig. 1, two short insulating pads 4 are arranged on the temperature-resistant sacrificial anode 2, and a locking sleeve 5 is arranged on each of the short insulating pads 4. Figure 1 As shown in Fig. 1, the locking sleeve 5 is sleeved on the corresponding short insulating pad 4, a threaded locking cap 6 is sleeved on the locking sleeve 5, and a guide cylinder 9 is sleeved on one end of the locking sleeve 5.

[0043] In the above scheme, the locking sleeve 5 and the locking cap 6 are matched to fix the two ends of the temperature-resistant sacrificial anode 2, and also fix one end of the guide cylinder 9.

[0044] In some possible embodiments, referring to Fig. 1, the guide cylinder 9 is sleeved with a locking nut at one end away from the temperature-resistant sacrificial anode 2. Figure 1 As shown in Fig. 1, the center pipe 1 is provided with an outer thread matched with the locking nut, and the locking nut is used to fix one end of the guide cylinder 9 away from the temperature-resistant sacrificial anode 2.

[0045] In some possible embodiments, referring to Fig. 1, a sleeve coupling 7 is arranged at either end of the center pipe 1. Figure 1 As shown in Fig. 1, the sleeve coupling 7 is used to connect the oil pipe.

[0046] In some possible embodiments, referring to Fig. 1, the outer peripheral wall of the center pipe 1 is coated with a polyethylene coating. Figure 1 As shown in Fig. 1, the polyethylene coating is used to improve the corrosion resistance and wear resistance of the center pipe 1.

[0047] The specific embodiments are only an explanation of the utility model, and are not a limitation of the utility model, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as the modifications are within the protection scope of the utility model, they are protected by the patent law.

Claims

1. An oil and water well casing corrosion protection device, characterized by, The anticorrosion assembly is sleeved on the central pipe (1), and comprises: a long insulating bushing (3) sleeved on the central pipe (1); two short insulating pads (4) respectively connected at two ends of the long insulating bushing (3) and sleeved on the central pipe (1); a temperature-resistant sacrificial anode (2) sleeved on the long insulating bushing (3); a short insulating bushing (8) sleeved on the central pipe (1); a guide cylinder (9) sleeved on the short insulating bushing (8); a plurality of spring contact arms (10) uniformly arranged along the circumferential direction of the guide cylinder (9), both ends of the spring contact arm (10) being located at both ends of the length direction of the guide cylinder (9), and any end of the spring contact arm (10) being connected with the temperature-resistant sacrificial anode (2); wherein a sleeve is sleeved on the temperature-resistant sacrificial anode (2), and the spring contact arm (10) abuts against the inner wall of the sleeve.

2. The corrosion protection device for oil and water well casings according to claim 1, characterized in that, Both the short insulating pads (4) are provided with locking sleeves (5) sleeved thereon, and the locking sleeves (5) are provided with threadedly connected locking caps (6). One end of the guide cylinder (9) is sleeved on the locking sleeve (5), and the locking cap (6) is used for fixing one end of the guide cylinder (9) when cooperating with the locking sleeve (5).

3. The corrosion protection device for oil and water well casings according to claim 2, characterized in that, One end of the guide cylinder (9) away from the temperature-resistant sacrificial anode (2) is sleeved with a screw nut, the central pipe (1) is provided with an external thread matched with the screw nut, and the screw nut is used for fixing one end of the guide cylinder (9) away from the temperature-resistant sacrificial anode (2).

4. The corrosion protection device for oil and water well casings according to claim 3, characterized in that Any end of the central pipe (1) is provided with a tubing coupling (7) used for connecting an oil pipe.

5. The corrosion protection device for oil and water well casings according to claim 4, characterized in that, The outer circumferential wall of the central pipe (1) is coated with a polyethylene coating.

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