Corrosion monitoring device for outer wall of underground oil and gas pipeline and monitoring method thereof

Abstract

The invention discloses a corrosion monitoring device for the outer wall of an underground oil and gas pipeline and a monitoring method thereof, and relates to the technical field of oil and water well monitoring equipment.The device comprises a hanging piece unit and an outer sleeve, the hanging piece unit comprises a connecting cover, corrosion hanging pieces, a rear cover plate and a plurality of embedded plates, and the embedded plates are circularly distributed and fixed to one side of the connecting cover; an embedding hole is formed in the embedding plate, a rear cover plate is fixed to the bottom of the embedding hole in a sealed mode, the corrosion coupon is arranged on the upper end face of the embedding plate and adheres to the upper end face of the rear cover plate in the embedding hole, the coupon unit is inserted into the outer sleeve, a hollowed-out strip-shaped hole is formed in the position, corresponding to the coupon unit, of the side wall of the outer sleeve, and the corrosion coupon is embedded into the hollowed-out strip-shaped hole. And the outer side of the corrosion coupon is kept consistent with the outer edge surface of the outer sleeve. The assembly process is simple, the corrosion condition of the underground oil pipe can be conveniently analyzed, the corrosion rule is researched, guidance is provided for safe and efficient production of oil and gas wells, and the use effect is good.

Description

Technical Field

[0001] The invention relates to the technical field of oil and water well monitoring equipment, and in particular to a corrosion monitoring device for the outer wall of an underground oil and gas pipeline and a monitoring method thereof. Background Art

[0002] During the oil and gas production process, water, hydrogen sulfide, carbon dioxide, bacteria and various salt substances inside the oil pipe will cause oil pipe corrosion. In mild cases, it will cause local weight loss of the oil pipe and continuous accumulation of corrosion products on the inner wall of the oil pipe. In severe cases, the oil pipe will be perforated and fall into the well, causing the oil pipe to fail.

[0003] Commonly used corrosion detection methods are generally corrosion hanging plate method, thickness measurement method, resistance probe method, electrochemical method and other methods. At present, the corrosion hanging plate method is the most commonly used method in corrosion detection. It can observe the surface morphology of the sample, analyze the surface corrosion products, and thus determine the type of corrosion. For example, the Chinese patent with publication number CN113958306A discloses a downhole oil pipe corrosion monitoring device and method, which does not require opening holes for hanging plates, and can accelerate the corrosion process of downhole hanging plates, shorten the corrosion monitoring cycle, and prevent downhole accidents. For example, the Chinese patent with publication number CN208473839U discloses a downhole hanging plate device, which is used to monitor the corrosion status of hanging plates with and without anode material protection at the same time, without affecting the normal operation of oil and water wells. For example, the Chinese patent with publication number CN219121999U discloses a downhole corrosion hanging plate device, which can protect the hanging plate from damage during the rise or fall of the oil pipe, and clean the sand and gravel near the hanging plate during daily use to prevent the corrosion of the hanging plate from aggravating and improve the monitoring effect.

[0004] However, the above-mentioned existing downhole corrosion monitoring devices mainly adopt the "wellbore hanging ring short section method" when in use. There are many threaded connection parts, which leads to many factors affecting corrosion monitoring. At the same time, the operation is cumbersome and the operation intensity is high. The disassembly and assembly of the hanging piece often require the cooperation of multiple people to complete, and the installation and disassembly are difficult.

[0005] To this end, the present application provides a corrosion monitoring device for the outer wall of an underground oil and gas pipeline to solve the above-mentioned technical problems. Summary of the invention

[0006] The purpose of this application is to provide a corrosion monitoring device for the outer wall of a downhole oil and gas pipeline, which not only has a simple assembly process, but also is convenient for analyzing the corrosion condition of the downhole oil pipeline, studying its corrosion law, providing guidance for the safe and efficient production of oil and gas wells, and has a good use effect.

[0007] To achieve the above-mentioned purpose, on the one hand, the present application provides the following technical solutions: a corrosion monitoring device for the outer wall of a downhole oil and gas pipeline, comprising a hanging plate unit and an outer sleeve, the hanging plate unit comprising a connecting cover, a corrosion hanging plate, a rear cover plate and a panel, a plurality of the panel plates are provided and are circularly distributed and fixed on one side of the connecting cover, an embedding hole is opened on the panel plate, the rear cover plate is sealed and fixed at the bottom of the embedding hole, the corrosion hanging plate is arranged on the upper end surface of the panel plate and glued to the upper end surface of the rear cover plate in the embedding hole, and the hanging plate unit is inserted into the outer sleeve, and the side wall of the outer sleeve is provided with a hollow strip hole corresponding to the position of the hanging plate unit, the hollow strip hole is for the corrosion hanging plate to be embedded, and the outer side of the corrosion hanging plate is kept consistent with the outer edge surface of the outer sleeve.

[0008] As a further preferred solution, the connecting cover is placed at one end of the outer sleeve as the hanging plate unit is inserted into the outer sleeve and is in an interference fit, and a plurality of nuts are provided at the end of the outer sleeve and fixed with bolts.

[0009] As a further preferred solution, a sealing ring is installed between the connecting cover and the end of the outer sleeve.

[0010] As a further preferred solution, the material of the corrosion hanging piece is consistent with the material of the outer wall of the monitored downhole oil and gas pipeline.

[0011] As a further preferred solution, the outer sleeve is provided with a plurality of hollow strip holes corresponding to the number of the corrosion hanging sheets, and the hollow strip holes are evenly distributed along the circumferential direction of the side wall of the outer sleeve, and the corrosion hanging sheets of the same material are symmetrically distributed on the outer sleeve.

[0012] As a further preferred solution, the outer sleeve is made of a plated material with a strength of at least 735 MPa.

[0013] As a further preferred solution, the hanging piece unit and the outer sleeve are jointly sleeved on the oil pipe, and both ends of the hanging piece unit and the outer sleeve are matched with clamping hoops for limiting and anti-slipping, and the clamping hoops are fixed on the oil pipe.

[0014] In a second aspect, an embodiment of the present application provides a monitoring method of a corrosion monitoring device for an outer wall of a downhole oil and gas pipeline, the method comprising:

[0015] Step S1, obtaining first data of the corrosion hanger, and sleeve the corrosion monitoring device for the outer wall of the downhole oil and gas pipeline on the outer wall of the oil pipe so that it slides down along the outer wall of the oil pipe to the bottom of the well, wherein the first data includes the mass, area and density of the corrosion hanger before entering the well;

[0016] Step S2, after the first monitoring time period, the corrosion monitoring device on the outer wall of the downhole oil and gas pipeline is salvaged out of the well, and second data of the corrosion hanging piece after being salvaged out of the well is recorded, wherein the second data includes the mass and pitting depth of the corrosion hanging piece;

[0017] Step S3: Calculate the average corrosion rate and the maximum pitting rate of the corrosion coupon based on the first data and the second data, and then analyze the corrosion condition of the oil pipe.

[0018] In summary, the technical effects and advantages of the present invention are as follows:

[0019] 1. The present invention optimizes the design of the monitoring position of the hanging plate by taking into account the differences in the flow state, temperature and pressure of the downhole liquid. Compared with the multi-bolt fixing method in the prior art, the assembly process of the device is simpler. At the same time, the corrosion test piece does not need to be fixed by drilling holes, which avoids the problem of damaging its metal structure and affecting the accuracy due to the opening of the hanging plate. After the device is installed, the corrosion hanging plate conforms to the flow rate and flow state of the original fluid in the well, and the measurement data is accurate.

[0020] 2. The present invention and its use method have a broad spectrum and can be applied to the monitoring of the annulus of any oil and water wells. It has strong versatility, low construction risk, and lower cost. It can effectively monitor the corrosion environment of each well section underground, has good use effect, and can provide effective guidance for the selection of anti-corrosion materials in the later stage.

[0021] 3. The present invention, by comparing the corrosion results of the traditional hanging piece weight loss method, can analyze the corrosion condition of the downhole oil pipe, so as to further identify the corrosion category, and can analyze the corrosion type of the downhole oil pipe according to the corrosion shape on the surface of the corrosion hanging piece, study its corrosion law, and provide guidance for the safe and efficient production of oil and gas wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 It is a schematic diagram of the three-dimensional structure of the underground corrosion monitoring device of the present invention;

[0024] Figure 2 It is a schematic diagram of the structural disassembly of the underground corrosion monitoring device of the present invention;

[0025] Figure 3 It is the parts diagram of the corrosion hanging piece of the present invention;

[0026] Figure 4is a schematic diagram of a panel of the present invention;

[0027] Figure 5 It is a schematic diagram of the rear cover plate of the present invention;

[0028] Figure 6 This is a schematic diagram of the coordination of the corrosion hanging piece unit of the present invention;

[0029] Figure 7 This is a schematic diagram of the outer sleeve structure of the present invention;

[0030] Figure 8 It is the parts diagram of the connecting cover unit of the present invention;

[0031] Fig. 9 It is the parts diagram of the clamping sleeve of the present invention;

[0032] Fig.10 Schematic diagram of the overall structure of the present invention installed on an oil pipe.

[0033] Figure numerals: 1, connecting cover; 2, corrosion hanging piece; 3, rear cover plate; 4, panel; 5, hanging piece unit; 6, outer sleeve; 7, connecting cover unit; 8, nut; 9, clamping ring; 10, oil pipe. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Example 1

[0036] refer to Figure 1 and Figure 2 The corrosion monitoring device for the outer wall of a downhole oil and gas pipeline shown in the figure comprises a hanging plate unit 5 and an outer sleeve 6, wherein the Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, the hanging piece unit 5 includes a connection cover 1, a corrosion hanging piece 2, a rear cover plate 3 and a panel 4. The panel 4 is provided with a plurality of panels and is circularly distributed and fixed to one side of the connection cover 1. The panel 4 is provided with an embedding hole, and the rear cover plate 3 is fixed to the bottom of the embedding hole by screws. A sealing adhesive is applied between the rear cover plate 3 and the panel 4 to form a seal, and the corrosion hanging piece 2 is arranged on the upper end surface of the panel 4 and is bonded to the upper end surface of the rear cover plate 3 in the embedding hole by epoxy resin on the back side, thereby forming the hanging piece unit 5.

[0037] In the specific implementation, in this embodiment, if Figure 2and Figure 7 As shown, a plurality of connection units 7 are fixed to the side surface of the connection cover 1 at equal intervals along the circumferential direction, and the panel 4 is fixed to the outer side of the connection unit 7, so that the panel 4 is fixed to the connection cover 1. In this embodiment, the material of the panel 4 can be selected from but not limited to polytetrafluoroethylene material, which has the advantages of high temperature resistance (can be used for a long time at -180 to 260°C), acid and alkali resistance, etc.

[0038] The hanging sheet unit 5 is inserted into the outer sleeve 6, and the outer sleeve 6 is as shown in FIG. Figure 7 As shown, the side wall of the outer sleeve 6 is provided with hollow strip holes corresponding to the position of the hanging sheet unit 5, and the hollow strip holes are used for the corrosion hanging sheet 2 to be embedded, and the outer side of the corrosion hanging sheet 2 is kept consistent with the outer edge surface of the outer sleeve 6. At the same time, the hanging sheet unit 5 only leaves the top surface for testing, and the other surfaces are sealed with resin to avoid contact with the gas-liquid-solid in the annulus. In specific implementation, the corrosion hanging sheet 2 is a trapezoidal inclined surface, and at the same time, the hollow strip holes around the outer sleeve 6 are a trapezoidal inclined surface structure matched therewith. Therefore, when installing the hanging sheet structure at this place, it is necessary to first apply the connection sealing material on the four sides of the trapezoidal surface of the hollow strip holes of the outer sleeve 6, and then install the hanging sheet unit 5. After installation, the contact position of the corrosion hanging sheet 2 and the outer sleeve 6 is sealed with resin to prevent liquid from invading the side wall groove.

[0039] The connection cover 1 is placed at one end of the outer sleeve 6 as the hanging plate unit 5 is inserted into the outer sleeve 6, and is in an interference fit. A plurality of nuts 8 are provided at the end of the outer sleeve 6, and the connection cover 1 is fixed with bolts. In a specific implementation, a sealing ring is installed between the connection cover 1 and the end of the outer sleeve 6 to form a seal. There are a plurality of hollow bar holes on the outer sleeve 6 corresponding to the number of the corrosion hanging plates 2, and they are evenly distributed along the circumferential direction of the side wall of the outer sleeve 6. In a specific implementation, in this embodiment, the material of the corrosion hanging plates 2 is consistent with the material of the outer wall of the monitored downhole oil and gas pipeline to ensure the corrosion monitoring effect of the outer wall of the oil and gas pipeline, and the outer sleeve 6 is made of a coating material with a strength of at least 735MPa.

[0040] However, in other embodiments, the corrosion hangers 2 are also made of different types of materials, so that test hangers of different materials can be installed on the device for downhole testing, but the corrosion hangers 2 of the same material need to be symmetrically distributed on the outer sleeve 6.

[0041] Reference Fig. 9 and Fig.10As shown, the hanging piece unit 5 and the outer sleeve 6 are sleeved on the oil pipe 10 together, and the two ends of the hanging piece unit 5 and the outer sleeve 6 are matched with a clamping hoop 9 for limiting and preventing slipping, and the clamping hoop 9 is fixed on the oil pipe 10. In specific implementation, the inner diameter of the outer sleeve 6 is consistent with the outer diameter of the oil pipe 10, and the outer diameter of the outer sleeve 6 does not exceed the outer diameter of the standard oil pipe 10 coupling.

[0042] Example 2

[0043] This embodiment is based on Embodiment 1 and is used to further illustrate a monitoring method based on a corrosion monitoring device for the outer wall of a downhole oil and gas pipeline. The method includes:

[0044] Step S1, obtaining first data of the corrosion hanger 2, and sleeve the corrosion monitoring device for the outer wall of the downhole oil and gas pipeline on the outer wall of the oil pipe 10 so that it slides down along the outer wall of the oil pipe to the bottom of the well, wherein the first data includes the mass, area and density of the corrosion hanger 2 before entering the well;

[0045] Step S2, after the first monitoring time period, the corrosion monitoring device on the outer wall of the downhole oil and gas pipeline is salvaged out of the well, and second data of the corrosion hanging piece 2 after being salvaged out of the well is recorded, wherein the second data includes the mass and pitting depth of the corrosion hanging piece 2;

[0046] Step S3, calculating the average corrosion rate and the maximum pitting rate of the corrosion coupon 2 based on the first data and the second data, and then analyzing the corrosion condition of the oil pipe 10.

[0047] In summary, the working principle of the present invention is as follows: when using the corrosion monitoring device for the outer wall of the downhole oil and gas pipeline, before lowering the device into the well, first record the mass M0, total area A, and density ρ of the corrosion hanger 2, then put the device on the outside of the oil pipe 10, and limit the device by fixing two clamping hoops 9 on the outside of the oil pipe 10 to prevent it from sliding on the oil pipe 10. After performing these operations, the device is lowered into the bottom of the well along with the oil pipe 10.

[0048] After a certain period of time, the device can be salvaged out of the well, and the monitoring time T and the data of the corrosion hanging piece 2 after entering the well are recorded, and the data include the mass M and the pitting depth I of the corrosion hanging piece 2.

[0049] Finally, by comparing the relevant data of the corrosion coupon 2 before and after entering the well, the average corrosion rate C and the maximum pitting rate E are calculated to analyze the corrosion condition of the downhole oil pipe 10 and predict the service life of the oil pipe 10. Compared with the corrosion results of the traditional coupon weight loss method, the present device can analyze the corrosion condition of the downhole oil pipe 10, so as to further identify the corrosion category, and can analyze the corrosion type of the downhole oil pipe 10 according to the corrosion shape on the surface of the corrosion coupon 2, study its corrosion law, and provide guidance for the safe and efficient production of oil and gas wells. Therefore, the use effect of the present device is better.

[0050] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A corrosion monitoring device for the outer wall of a downhole oil and gas pipeline, comprising a hanging plate unit (5) and an outer sleeve (6), characterized in that: The hanging piece unit (5) comprises a connection cover (1), a corrosion hanging piece (2), a rear cover plate (3) and a panel (4); a plurality of the panel (4) are provided and are circularly distributed and fixed to one side of the connection cover (1); an embedding hole is provided on the panel (4); the rear cover plate (3) is sealed and fixed to the bottom of the embedding hole; the corrosion hanging piece (2) is arranged on the upper end surface of the panel (4) and is glued to the upper end surface of the rear cover plate (3) in the embedding hole; the hanging piece unit (5) is inserted into the outer sleeve (6); a hollow strip hole is provided on the side wall of the outer sleeve (6) corresponding to the position of the hanging piece unit (5); the hollow strip hole is used for the corrosion hanging piece (2) to be embedded in the hollow strip hole, and the outer side of the corrosion hanging piece (2) is kept consistent with the outer edge surface of the outer sleeve (6).

2. The corrosion monitoring device for the outer wall of a downhole oil and gas pipeline according to claim 1 is characterized in that: The connection cover (1) is placed at one end of the outer sleeve (6) as the hanging piece unit (5) is inserted into the outer sleeve (6) and is in an interference fit. A plurality of nuts (8) are provided at the end of the outer sleeve (6) and are fixed with bolts.

3. The corrosion monitoring device for the outer wall of a downhole oil and gas pipeline according to claim 2 is characterized in that: A sealing ring is installed between the connecting cover (1) and the end of the outer sleeve (6).

4. The corrosion monitoring device for the outer wall of a downhole oil and gas pipeline according to claim 1 is characterized in that: The material of the corrosion hanging piece (2) is consistent with the material of the outer wall of the monitored underground oil and gas pipeline.

5. The corrosion monitoring device for the outer wall of a downhole oil and gas pipeline according to claim 1 is characterized in that: The outer sleeve (6) is provided with a plurality of hollow strip holes corresponding to the number of the corrosion hanging pieces (2), and the holes are evenly distributed along the circumferential direction of the side wall of the outer sleeve (6), and the corrosion hanging pieces (2) made of the same material are symmetrically distributed on the outer sleeve (6).

6. The corrosion monitoring device for the outer wall of a downhole oil and gas pipeline according to claim 1 is characterized in that: The outer sleeve (6) is made of a plated material and has a strength of at least 735 MPa.

7. The corrosion monitoring device for the outer wall of a downhole oil and gas pipeline according to claim 1 is characterized in that: The hanging piece unit (5) and the outer sleeve (6) are jointly sleeved on the oil pipe (10), and both ends of the hanging piece unit (5) and the outer sleeve (6) are matched with clamping hoops (9) for limiting and preventing slipping, and the clamping hoops (9) are fixed on the oil pipe (10).

8. A monitoring method for the corrosion monitoring device of the outer wall of a downhole oil and gas pipeline according to any one of claims 1 to 7, characterized in that: The method comprises: Step S1, obtaining first data of the corrosion hanger (2), and sleeve the corrosion monitoring device for the outer wall of the downhole oil and gas pipeline on the outer wall of the oil pipe (10) so that it slides down along the outer wall of the oil pipe to the bottom of the well, wherein the first data includes the mass, area and density of the corrosion hanger (2) before entering the well; Step S2, after the first monitoring time period has passed, the corrosion monitoring device on the outer wall of the downhole oil and gas pipeline is salvaged out of the well, and second data of the corrosion hanging piece (2) after being salvaged out of the well is recorded, wherein the second data includes the mass and pitting depth of the corrosion hanging piece (2); Step S3: calculating the average corrosion rate and the maximum pitting rate of the corrosion coupon (2) based on the first data and the second data, and then analyzing the corrosion condition of the oil pipe (10).

Images