Surface alloying of tungsten for anticorrosion and cathodic protection of sucker rods

Abstract

Surface tungsten alloy impregnation type anticorrosion sucker rod cathode protector relates to the technical field of sucker rod, including sucker rod, the sucker rod includes connected sucker rod short section and centralizer section, the sucker rod short section is equipped with the protective material layer, the sucker rod short section is still fixedly connected with the screen mesh cylinder of covering protective material layer, the centralizer section includes upper connecting rod section and lower connecting rod section, the lower end of upper connecting rod section and the upper end of lower connecting rod section are detachably connected, the centralizer sleeve is rotatably installed between upper connecting rod section and lower connecting rod section by using restraint together, the opposite outer wall of centralizer sleeve is respectively provided with spiral flow guide groove.The utility model solves the problem that the material of the traditional technology in the sucker rod is easy to fall off in use, and the material is easy to enter the pump body, causing the problem of pump jamming.

Description

Technical Field

[0001] This utility model relates to the field of sucker rod technology, specifically to a cathodic protector for a surface-plated tungsten alloy-coated anti-corrosion sucker rod. Background Technology

[0002] The sucker rod is a crucial component in rod-pump oil extraction. Constantly reciprocating in the downhole oil-water medium, it generates friction with the tubing, causing wear and tear, particularly noticeable in directional, highly deviated, and horizontal wells. Furthermore, as oilfield development progresses into the later stages, the produced fluids and injected formation water have higher salinity and contain strong electrolytes such as sulfides, carbon dioxide, oxygen, and sulfate-reducing bacteria. Since the materials of the sucker rod, couplings, and tubing vary, their electrode potentials in these electrolytes also differ. This creates a galvanic cell reaction on the surface of the sucker rod or coupling, causing it to lose electrons and undergo electrochemical corrosion, acting as the anode. The environment in which the sucker rod or coupling is located determines the severity of its corrosion damage. Due to the harsh environment in which the pumping well is located, "high temperature, high mineralization, and high water content" all play a catalytic role in promoting the corrosion reaction rate. The high chloride ion content provides the conditions and opportunities for pitting corrosion to form on the sucker rod or coupling, accelerating the electrochemical corrosion rate and ultimately leading to corrosion failure of the sucker rod or coupling.

[0003] Sucker rods play a crucial role in crude oil production using rod pumps. If a sucker rod malfunctions, normal well production will be halted, leading to well shutdowns, workover operations, and significant losses for the oilfield. Regarding corrosion of sucker rods or couplings, the commonly used method in China is to add corrosion inhibitors to the well. While this can mitigate corrosion to some extent, it is difficult and labor-intensive to implement in the field, and its effectiveness is poor in wells with uneven wear or high levels of casing gas.

[0004] A prior art patent, CN202047760U, discloses a rod body and couplings at both ends. The rod body has an alloy sleeve made of a metal more reactive than steel on its outer periphery. A stainless steel sleeve is fitted over the alloy sleeve. A centralizer, fitted onto the outside of the rod body, is located between the alloy sleeve, the stainless steel sleeve, and the couplings. The outer wall of the stainless steel sleeve has several through holes. When applied in oil and water wells, this invention can create a protective potential difference, preventing and mitigating electrochemical corrosion, slowing down the electrochemical corrosion rate of the sucker rod or couplings, and extending their service life.

[0005] With use, existing devices, including those mentioned above, have gradually revealed shortcomings in this technology, mainly in the following aspects:

[0006] First, with existing sucker rods, the protective material layer is easily worn away during use, leading to material detachment. This detached material can easily enter the pump body, causing pump jamming.

[0007] Secondly, existing sucker rods are straightened by a centralizer during use, but the centralizer hinders the flow of oil and affects the stability of the sucker rod during lifting and lowering.

[0008] Third, when the centralizer of the existing sucker rod wears out and fails, the entire sucker rod needs to be replaced, which increases production costs.

[0009] In conclusion, the existing technology obviously has inconveniences and defects in practical use, so it is necessary to improve it. Utility Model Content

[0010] In view of the shortcomings of the prior art, this utility model solves the problem that in the traditional technology, the protective material layer of the sucker rod is easily worn off during use, which can lead to the detached material entering the pump body and causing pump jamming.

[0011] To solve the above problems, this utility model provides the following technical solution:

[0012] A cathodic protector for corrosion-resistant sucker rods with tungsten alloy surface coating includes a sucker rod comprising a short section and a straightening section connected together. A protective material layer is provided on the short section of the sucker rod, and a screen cylinder covered with the protective material layer is also fixedly connected to the short section of the sucker rod.

[0013] The straightening section includes an upper connecting rod section and a lower connecting rod section. The lower end of the upper connecting rod section and the upper end of the lower connecting rod section are detachably connected. The upper connecting rod section and the lower connecting rod section are rotatably mounted with a straightening sleeve using a constraint member. The outer walls of the straightening sleeve are respectively provided with spiral guide grooves.

[0014] As an optimized solution, the constraint member includes an upper positioning ring fixed to the upper connecting rod segment and a lower positioning ring segment fixed to the lower connecting rod segment, and the upper and lower ends of the straightening sleeve are rotatably constrained in the area between the upper positioning ring and the lower positioning ring segment.

[0015] As an optimized solution, the center of the straightening sleeve has a through-hole for mounting, and the upper end of the mounting hole has an upper bearing groove. An upper bearing is fitted into the upper bearing groove, the inner ring of the upper bearing abuts against the upper positioning ring, and the outer ring of the upper bearing abuts against the upper bearing groove.

[0016] As an optimized solution, the lower port of the mounting hole is provided with a lower bearing groove, a lower bearing is installed in the lower bearing groove, the inner ring of the lower bearing abuts against the lower positioning ring, and the outer ring of the lower bearing abuts against the lower bearing groove.

[0017] As an optimized solution, the lower end of the upper connecting rod segment is fixedly connected to an upper screw, and the upper end of the lower connecting rod segment is fixedly connected to a lower screw. The upper screw and the lower screw are threaded together onto the connecting sleeve.

[0018] As an optimized solution, an upper mounting groove is horizontally opened on the outer wall of the connecting sleeve, and an upper anti-disengagement knob is threaded into the upper mounting groove, with the end of the upper anti-disengagement knob abutting against the upper screw.

[0019] As an optimized solution, an upper anti-detachment ring groove is coaxially formed on the outer wall of the upper screw, and the end of the upper anti-detachment knob abuts against the upper anti-detachment ring groove.

[0020] As an optimized solution, a lower mounting groove is horizontally opened on the outer wall of the connecting sleeve, and a lower anti-disengagement knob is threaded into the lower mounting groove, with the end of the lower anti-disengagement knob abutting against the lower screw.

[0021] As an optimized solution, a lower anti-detachment ring groove is coaxially formed on the outer wall of the lower screw, and the end of the lower anti-detachment knob abuts against the lower anti-detachment ring groove.

[0022] As an optimized solution, the spiral guide groove is provided with an upper operating hole and a lower operating hole that correspond to the upper mounting groove and the lower mounting groove, respectively.

[0023] Compared with the prior art, the beneficial effects of this utility model are:

[0024] The screen is made of stainless steel and is fully encased in an aluminum-magnesium alloy casing. The screen tube is designed with screen holes to prevent material from falling off due to the consumption of the aluminum-magnesium alloy material layer during operation, effectively preventing pump jamming.

[0025] By dividing the sucker rod into an upper connecting rod section and a lower connecting rod section, a detachable connection of the centralizing sleeve is achieved. When the centralizing sleeve fails due to wear, it can be replaced by the centralizing sleeve instead of the entire sucker rod, thus reducing maintenance costs.

[0026] By setting a large-curvature spiral guide groove on the relative outer wall of the centralizing sleeve, the contact surface is increased to a greater extent of corrosion and wear, providing protection for a longer period of time. In addition, the large-curvature spiral guide groove has a large flow area, which can effectively reduce the lifting resistance of the sucker rod and improve the operating stability of the sucker rod. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0028] Figure 1 This is a schematic diagram of the structure of this utility model;

[0029] Figure 2 This is a structural schematic diagram of the constraint component of this utility model.

[0030] In the diagram: 1-Short section of sucker rod; 2-Protective material layer; 3-Screw cylinder; 4-Helical guide groove; 5-Upper positioning step; 6-Upper bearing; 7-Lower positioning step; 8-Lower bearing; 9-Upper screw; 10-Lower screw; 11-Connecting sleeve; 12-Upper anti-detachment ring groove; 13-Upper anti-detachment knob; 14-Lower anti-detachment ring groove; 15-Lower anti-detachment knob; 16-Upper operating hole; 17-Lower operating hole; 18-Upper connecting rod section; 19-Lower connecting rod section; 20-Straightening sleeve. Detailed Implementation

[0031] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0032] like Figure 1 and Figure 2 As shown, a tungsten alloy-plated anti-corrosion cathodic protector for sucker rods includes a sucker rod, which comprises a short sucker rod section 1 and a straightening section connected together. A protective material layer 2 is provided on the short sucker rod section 1, and a screen cylinder 3 covering the protective material layer 2 is also fixedly connected to the short sucker rod section 1.

[0033] The straightening section includes an upper connecting rod section 18 and a lower connecting rod section 19. The lower end of the upper connecting rod section 18 and the upper end of the lower connecting rod section 19 are detachably connected. The upper connecting rod section 18 and the lower connecting rod section 19 are rotatably mounted with a straightening sleeve 20 using a constraint member. The outer walls of the straightening sleeve 20 are respectively provided with spiral guide grooves 4.

[0034] The constraint includes an upper positioning ring 5 fixed to the upper connecting rod segment 1 and a lower positioning ring segment 7 fixed to the lower connecting rod segment 2. The upper and lower ends of the straightening sleeve 3 are rotatably constrained in the area between the upper positioning ring 5 and the lower positioning ring segment 7.

[0035] The center of the straightening sleeve 3 has a through-hole for mounting. The upper end of the mounting hole has a groove for the upper bearing 6. The upper bearing 6 is fitted into the groove. The inner ring of the upper bearing 6 abuts against the upper positioning ring 5, and the outer ring of the upper bearing 6 abuts against the groove of the upper bearing 6.

[0036] The lower end of the mounting hole is provided with a groove for a lower bearing 8. The lower bearing 8 is installed in the groove for the lower bearing 8. The inner ring of the lower bearing 8 abuts against the lower positioning ring 7, and the outer ring of the lower bearing 8 abuts against the groove for the lower bearing 8.

[0037] The lower end of the upper connecting rod segment 1 is fixedly connected to the upper screw 9, and the upper end of the lower connecting rod segment 2 is fixedly connected to the lower screw 10. The upper screw 9 and the lower screw 10 are threadedly connected to the connecting sleeve 11.

[0038] The outer wall of the connecting sleeve 11 is horizontally provided with an upper mounting groove, and an upper anti-disengagement knob 13 is threadedly connected in the upper mounting groove. The end of the upper anti-disengagement knob 13 abuts against the upper screw 9.

[0039] An upper anti-detachment ring groove 12 is coaxially formed on the outer wall of the upper screw 9, and the end of the upper anti-detachment knob 13 abuts against the upper anti-detachment ring groove 12.

[0040] A lower mounting groove is horizontally opened on the outer wall of the connecting sleeve 11. A lower anti-disengagement knob 15 is threadedly connected in the lower mounting groove. The end of the lower anti-disengagement knob 15 abuts against the lower screw 10.

[0041] A lower anti-detachment ring groove 14 is coaxially formed on the outer wall of the lower screw 10, and the end of the lower anti-detachment knob 15 abuts against the lower anti-detachment ring groove 14.

[0042] The spiral guide groove 4 is provided with an upper operating hole 16 and a lower operating hole 17, which correspond to the upper mounting groove and the lower mounting groove, respectively.

[0043] The protective material layer is an aluminum-magnesium alloy sacrificial anode protective material layer. Cathodic protection is one of the most effective methods to prevent electrochemical corrosion of metals. The sacrificial anode method involves electrically connecting an aluminum-magnesium alloy with a more negative potential to the protected sucker rod string structure. Through the continuous consumption and dissolution of the electronegative alloy, a protective current is provided to the protected rod string, thus protecting it.

[0044] The two ends of the screen are fixed to the stage of the sucker rod.

[0045] The working principle of this device is as follows:

[0046] The screen is made of stainless steel and is fully encased in an aluminum-magnesium alloy casing. The screen tube is designed with screen holes to prevent material from falling off due to the consumption of the aluminum-magnesium alloy material layer during operation, effectively preventing pump jamming.

[0047] By dividing the sucker rod into an upper connecting rod section 1 and a lower connecting rod section 2, a detachable connection of the centralizing sleeve 3 is achieved. When the centralizing sleeve 3 fails due to wear, it can be replaced by replacing the centralizing sleeve 3 instead of replacing the entire sucker rod, thus reducing maintenance costs.

[0048] By setting a large-curvature spiral guide groove 4 on the relative outer wall of the centralizing sleeve 3, the contact surface is increased to a larger amount of corrosive wear, providing longer protection. In addition, the large-curvature spiral guide groove 4 has a large flow area, which can effectively reduce the lifting resistance of the sucker rod and improve the operating stability of the sucker rod.

[0049] During installation, first, mount the upper bearing 6 onto the upper connecting rod section 1, and use the upper positioning ring 5 to position one end of the upper bearing 6 against it. Similarly, install the lower bearing 8. Then, insert the connecting sleeve 11 into the mounting hole, insert the opposite ends of the upper connecting rod section 1 and the lower connecting rod section 2 into the mounting hole and rotate them to screw the lower screw 10 and the upper thread into the connecting sleeve 11 and tighten them. Then, by rotating the straightening sleeve 3, align the lower operating hole 17 with the lower mounting groove and the upper operating hole 16 with the upper mounting groove. Screw the lower anti-detachment knob 15 and the upper anti-detachment knob 13 into the lower mounting groove and the upper mounting groove respectively to lock them in place. The installation is complete, which is convenient and quick.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and they should all be covered within the scope of the claims and specification of this utility model.

Claims

1. A cathodic protector for corrosion-resistant sucker rods with tungsten alloy surface coating, characterized in that: The device includes a sucker rod, which comprises a short sucker rod section (1) and a straightening section connected together. The short sucker rod section (1) is provided with a protective material layer (2), and a screen cylinder (3) covering the protective material layer (2) is also fixedly connected to the short sucker rod section (1). The straightening section includes an upper connecting rod section (18) and a lower connecting rod section (19). The lower end of the upper connecting rod section (18) and the upper end of the lower connecting rod section (19) are detachably connected. The upper connecting rod section (18) and the lower connecting rod section (19) are rotatably mounted with a straightening sleeve (20) using a constraint member. The outer walls of the straightening sleeve (20) are respectively provided with spiral guide grooves (4).

2. The cathodic protector for anti-corrosion sucker rods with surface tungsten alloy diffusion coating as described in claim 1, characterized in that: The constraint includes an upper positioning ring (5) fixed to the upper connecting rod segment (1) and a lower positioning ring (7) fixed to the lower connecting rod segment (2). The upper and lower ends of the straightening sleeve (3) are rotatably constrained in the area between the upper positioning ring (5) and the lower positioning ring (7).

3. The cathodic protection device for anti-corrosion sucker rods with surface tungsten alloy diffusion coating as described in claim 1, characterized in that: The center of the straightening sleeve (3) has a through-hole for mounting. The upper end of the mounting hole has a groove for an upper bearing (6). An upper bearing (6) is fitted into the groove for the upper bearing (6). The inner ring of the upper bearing (6) abuts against the upper positioning ring (5), and the outer ring of the upper bearing (6) abuts against the groove for the upper bearing (6).

4. The cathodic protector for anti-corrosion sucker rods with surface tungsten alloy diffusion coating as described in claim 1, characterized in that: The lower end of the mounting hole is provided with a lower bearing (8) groove, and a lower bearing (8) is installed in the lower bearing (8) groove. The inner ring of the lower bearing (8) abuts against the lower positioning ring (7), and the outer ring of the lower bearing (8) abuts against the lower bearing (8) groove.

5. The cathodic protector for anti-corrosion sucker rods with surface tungsten alloy diffusion coating as described in claim 1, characterized in that: The lower end of the upper connecting rod segment (1) is fixedly connected to an upper screw (9), and the upper end of the lower connecting rod segment (2) is fixedly connected to a lower screw (10). The upper screw (9) and the lower screw (10) are threaded together onto the connecting sleeve (11).

6. The cathodic protection device for anti-corrosion sucker rod with surface tungsten alloy diffusion coating as described in claim 1, characterized in that: The outer wall of the connecting sleeve (11) is provided with an upper mounting groove, and an upper anti-detachment knob (13) is threaded into the upper mounting groove. The end of the upper anti-detachment knob (13) abuts against the upper screw (9).

7. The cathodic protector for anti-corrosion sucker rods with surface tungsten alloy diffusion coating as described in claim 1, characterized in that: The upper screw (9) has an upper anti-detachment ring groove (12) coaxially formed on its outer wall, and the end of the upper anti-detachment knob (13) abuts against the upper anti-detachment ring groove (12).

8. The cathodic protection device for anti-corrosion sucker rods with surface tungsten alloy diffusion coating as described in claim 1, characterized in that: The outer wall of the connecting sleeve (11) is horizontally provided with a lower mounting groove, and a lower anti-detachment knob (15) is threadedly connected in the lower mounting groove. The end of the lower anti-detachment knob (15) abuts against the lower screw (10).

9. The cathodic protector for anti-corrosion sucker rods with surface tungsten alloy diffusion coating as described in claim 1, characterized in that: The lower screw (10) has a lower anti-detachment ring groove (14) coaxially formed on its outer wall, and the end of the lower anti-detachment knob (15) abuts against the lower anti-detachment ring groove (14).

10. The cathodic protector for anti-corrosion sucker rods with surface tungsten alloy diffusion coating according to claim 1, characterized in that: The spiral guide groove (4) is provided with an upper operating hole (16) and a lower operating hole (17) that correspond to the upper mounting groove and the lower mounting groove, respectively.

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