A DC stray current corrosion evaluation method and system for oil and gas pipelines

Abstract

The present invention belongs to the field of information technology detection, and proposes a DC stray current corrosion evaluation method and system for oil and gas pipelines, the method comprising the following steps: obtaining the potential size of the pipeline and the potential size of the soil surface around the pipeline; calculating the pipeline potential deviation through the pipeline potential size and the potential size of the soil surface around the pipeline; screening out the potential core display pipeline according to the pipeline potential deviation; performing constant magnetic potential analysis on the potential core display pipeline to obtain the constant magnetic potential offset; and evaluating the current interference through the constant magnetic potential offset. The evaluation method according to the embodiment of the present invention can reflect the impact of the dynamic environment on the pipeline state in real time, and accurately and comprehensively evaluate the current interference of the oil and gas pipeline.

Description

Technical Field

[0001] The invention belongs to the field of oil and gas pipeline detection and evaluation, and in particular relates to a direct current stray current corrosion evaluation method and system for oil and gas pipelines. Background Art

[0002] Since the potential measurement of stray current interference evaluation in the "DC stray current corrosion evaluation method for high-strength steel for oil and gas pipelines under stress conditions" with Chinese patent publication number CN104122196A is usually concentrated in specific locations, key nodes or areas prone to corrosion (such as pipeline connections, near valves, etc.) of the pipeline, while ignoring the potential conditions of other parts, this limitation causes a large error in the potential state of the entire pipeline system. And because the potential change may vary due to factors such as the material of the pipeline, soil properties, and external interference sources, it is impossible to accurately capture the overall corrosion risk and potential change trend of the pipeline by relying solely on limited measurement points. During the operation of the pipeline, its potential will be affected by many factors, including the properties of the fluid, changes in the environment, external current interference, etc. These dynamic factors make the potential change in time and space. If only measurements are taken at fixed locations, these dynamic changes cannot be monitored in real time, which may lead to misjudgment of the actual condition of the pipeline, thereby affecting the accuracy of corrosion prediction.

[0003] In addition, local potential anomalies (such as coating damage, changes in soil resistivity, etc.) may occur at certain specific locations on the pipeline, and traditional methods fail to cover these areas during measurement, resulting in unscientific and unreasonable evaluation results. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, the first object of the present invention is to propose a DC stray current corrosion evaluation method for oil and gas pipelines, which can reflect the impact of the dynamic environment on the pipeline state in real time and accurately and comprehensively evaluate the current interference of the oil and gas pipelines;

[0005] The second object of the present invention is to provide a DC stray current corrosion evaluation system for oil and gas pipelines.

[0006] To achieve the above object, a first embodiment of the present invention provides a DC stray current corrosion evaluation method for oil and gas pipelines, the method comprising the following steps:

[0007] S100, obtaining the potential of the pipeline and the potential of the soil surface around the pipeline;

[0008] S200, calculating the pipeline potential deviation according to the pipeline potential and the potential of the soil surface around the pipeline;

[0009] S300, screening out the potential core display pipeline according to the pipeline potential deviation;

[0010] S400, performing a constant magnetic potential analysis on the potential nuclear display pipeline to obtain a constant magnetic potential offset;

[0011] S500, current disturbance evaluation by constant magnetopotential shift.

[0012] The evaluation method according to the embodiment of the present invention can reflect the impact of the dynamic environment on the pipeline status in real time, and accurately and comprehensively perform current interference evaluation on the oil and gas pipeline.

[0013] Since traditional potential measurements are usually concentrated at specific locations on the pipeline, such as key nodes or areas prone to corrosion (such as pipeline connections, near valves, etc.), while ignoring the potential conditions in other parts, this limitation will result in large errors in the potential status of the entire pipeline system.

[0014] Further, in order to solve the above problem, the method for obtaining the potential size of the pipeline and the potential size of the soil surface around the pipeline in step S100 includes: obtaining the potential size of the pipeline in each distance interval L by a potentiometer, wherein the distance interval L is set to [1, 50] meters; ISO(Li) is recorded as the potential size in the i-th distance interval Li of the pipeline, and LIS(Li) is recorded as the potential size of the soil surface around the i-th distance interval Li of the pipeline, wherein Li=[(i-1)*L, i*L], i=1, 2, ..., H, H∈[5, 100], i is the distance interval sequence number, the median of each potential size in all ISO(Li) is recorded as ISM, and the median of each potential size in all LIS(Li) is recorded as LIM;

[0015] The beneficial effect of this step is: by setting multiple distance intervals around the pipeline and using a potentiometer to fully obtain the potential information of the pipeline potential and the surrounding soil surface, it can effectively solve the limitation that the potential measurement of stray current interference evaluation in the "DC stray current corrosion evaluation method for high-strength steel for oil and gas pipelines under stress conditions" with Chinese patent publication number CN104122196A is usually concentrated in specific locations, key nodes or areas prone to corrosion of the pipeline; this step can not only capture the potential changes of the pipeline at different locations, but also reflect the impact of the dynamic environment on the pipeline state in real time, and reduce the impact of individual outliers. The pipeline potential and soil potential can reveal the degree of DC stray current interference, providing a solid data foundation for subsequent corrosion risk assessment and protection measures, thereby significantly enhancing the safety and maintenance efficiency of oil and gas pipelines.

[0016] Further, in step S200, calculating the pipeline potential deviation according to the pipeline potential and the potential of the soil surface around the pipeline includes:

[0017] Let D(Li) be the pipeline potential deviation within the i-th distance interval Li of the pipeline, where D(Li) is the difference between ISO(Li) and LIS(Li); create an empty sequence and record it as the potential deviation sequence DK, import all D(Li) into the potential deviation sequence, and record the average value in the potential deviation sequence as DM;

[0018] The pipeline potential deviation is the deviation between the pipeline potential and the soil potential, which can quantify the potential state of the pipeline and accurately evaluate the degree of current interference. This quantification process is the basis for subsequent corrosion risk assessment. A large value of D(Li) indicates that the pipeline is subject to strong DC stray current interference; the potential stability of the entire pipeline system can be judged by the average value of the potential deviation DM.

[0019] Further, in step S300, the potential core display pipeline is screened out according to the pipeline potential deviation, including:

[0020] S301, calculating the standard deviation of all pipeline potential deviations in the potential deviation sequence DK, classifying the pipeline potential deviations based on the standard deviations, and obtaining a first pipeline potential deviation range, a second pipeline potential deviation range, and a third pipeline potential deviation range;

[0021] The specific method is as follows: calculate the standard deviation of all pipeline potential deviations in the potential deviation sequence DK, and classify the potential deviation sequence internally by the standard deviation of all pipeline potential deviations in the potential deviation sequence DK; record the value of DM minus the standard deviation as DG, and the value of DM plus the standard deviation as DP, classify the pipeline potential deviations in the potential deviation sequence DK that are less than or equal to DG into the first pipeline potential deviation range Dn1; classify the pipeline potential deviations in the potential deviation sequence DK that are greater than DG and less than DP into the second pipeline potential deviation range Dn2; classify the pipeline potential deviations in the potential deviation sequence DK that are greater than or equal to DP into the third pipeline potential deviation range Dn3;

[0022] By calculating the difference between the ground potential information of the pipeline and the potential information of the surrounding soil surface (potential deviation), the system can accurately identify the pipeline intervals that are significantly affected by DC stray current interference. This screening is based on statistical analysis of potential deviation, including calculating the standard deviation and determining the range of different potential deviations, ensuring the accuracy and reliability of the screening results;

[0023] The intervals of the first pipeline potential deviation range Dn1, the second pipeline potential deviation range Dn2, and the third pipeline potential deviation range Dn3 are respectively recorded as [N, K1], [K2, Y1], and [Y2, MX], where the interval [N, K1] represents the first pipeline potential deviation range Dn1, where N is the minimum value in the potential deviation sequence DK, and K1 is the value closest to DG among all pipeline potential deviations less than or equal to DG in the potential deviation sequence DK. The interval [K2, Y1] represents the second pipeline potential deviation range Dn2, where K2 is the value closest to DG among all pipeline potential deviations greater than DG in the potential deviation sequence DK, and Y1 is the value closest to DP among all pipeline potential deviations less than DP in the potential deviation sequence DK. The interval [Y2, MX] represents the third pipeline potential deviation range Dn3, where Y2 is the value closest to DP among all pipeline potential deviations greater than or equal to DP in the potential deviation sequence DK, and MX is the maximum value in the potential deviation sequence DK.

[0024] S302, calculating a first potential deviation boundary MYa and a second potential deviation boundary MYb through the first pipeline potential deviation range Dn1, the second pipeline potential deviation range Dn2, and the third pipeline potential deviation range Dn3;

[0025] The pipeline potential deviation is divided into different ranges, and the core potential deviation is further distinguished and extracted by setting the first potential deviation boundary MYa and the second potential deviation boundary MYb. This multi-dimensional classification not only simplifies the analysis process, but also can finely distinguish the potential state, which is helpful to formulate subsequent corrosion risk management measures in a targeted manner.

[0026] S303, according to the boundary values ​​of the first potential deviation boundary MYa and the second potential deviation boundary MYb, the potential deviation data between the two boundary values ​​is extracted and recorded as the core potential deviation DK (Lj), and the pipeline interval corresponding to the core potential deviation DK (Lj) is marked as the potential core display pipeline;

[0027] The first potential deviation boundary MYa is the maximum value K1 in the first pipeline potential deviation range Dn1 minus the minimum potential deviation range difference, wherein the minimum potential deviation range difference is the product of K2 and the potential deviation stable balance ratio, wherein the potential deviation stable balance ratio is the ratio of K1×ISM to K2×LIM; the second potential deviation boundary MYb is the maximum value K1 in the first pipeline potential deviation range Dn1 plus the maximum potential deviation range difference, wherein the maximum potential deviation range difference is the product of K2 and the potential deviation abnormal balance ratio, wherein the potential deviation abnormal balance ratio is the ratio of Y1×ISM to (Y2+Y1)×LIM;

[0028] Extract all D (Li) between the first potential deviation boundary MYa and the second potential deviation boundary MYb, and record them as core potential deviation DK (Lj), where j is the pipeline distance interval number between the first potential deviation boundary MYa and the second potential deviation boundary MYb of the pipeline potential deviation, and record the pipeline corresponding to DK (Lj) as the potential core display pipeline;

[0029] Furthermore, the first potential deviation boundary MYa is based on the statistical analysis of the potential deviation to screen out the pipeline sections with potential deviations close to normal and small fluctuations, which are usually not subject to significant external interference or corrosion risks. Screening out pipeline sections with potential deviations close to normal and small fluctuations helps to concentrate monitoring resources, reduce the monitoring requirements for normal pipeline sections without significant potential deviations, and optimize monitoring efficiency and costs. The second potential deviation boundary MYb is used to exclude pipeline sections with large potential deviations but non-corrosion causes due to external magnetic fields or environmental factors around the pipeline (such as electromagnetic interference, changes in soil composition). Using the second potential deviation boundary MYb to help filter out these anomalies caused by external environmental interference rather than corrosion helps to exclude abnormal signals caused by non-corrosion reasons and avoid misjudgment or unnecessary monitoring. The core potential deviation is the potential deviation data between MYa and MYb, reflecting the areas affected by corrosion in the pipeline system. Through MYa and MYb, the core potential deviation can be focused on the pipeline sections subject to corrosion risks, and the interference of the external environment and normal pipeline sections can be eliminated, focusing on areas with high corrosion risks, thereby improving the effectiveness of monitoring.

[0030] The beneficial effects of this step are: dividing the pipeline potential deviation into different ranges, and further distinguishing and extracting the core potential deviation through the first potential deviation boundary MYa and the second potential deviation boundary MYb; this multi-dimensional classification not only simplifies the analysis process, but also can finely distinguish the potential state, which is helpful to formulate subsequent corrosion risk management measures in a targeted manner, and by screening the potential core display pipeline, it optimizes the allocation and use of monitoring resources, avoids single-type monitoring of the entire pipeline, saves cost and time, and improves monitoring efficiency and data processing speed.

[0031] Furthermore, in step S400, the method of performing constant magnetic potential analysis on the potential core display pipeline to obtain the constant magnetic potential offset includes:

[0032] The average magnetic field strength and potential offset of the potential core display pipeline in each time interval T are obtained by the Hall sensor, wherein the average magnetic field strength is the average value of all instantaneous magnetic field strengths in units of seconds in the time interval, wherein the time interval T is set to [0.5, 5] seconds; KMP(Tr) is denoted as the total magnetic field strength received by the potential core display pipeline in Tr, and DJMY(Tr, Lj) is denoted as the potential offset of the potential core display pipeline with serial number j in Tr, wherein Tr=[(r-1)*T, r*T], r=1, 2, ..., G, G∈[5, 100]; the minimum value among each KMP(Tr) is obtained and recorded as KMP(Tz), and Tz is recorded as the constant magnetic time, z∈[1, H];

[0033] Further, in step S500, the corrosion rate is evaluated by constant magnetic potential shift;

[0034] The average value of each DJMY (Tz, Lj) is recorded as the constant magnetic potential offset DJX, and the interference degree is evaluated by DJX. When the constant magnetic potential offset DJX ≥ 100mv, the corrosion rate is evaluated to be high, otherwise the corrosion rate is low; if the corrosion rate is high, DC discharge protection or other protective measures are required.

[0035] The beneficial effect of this step is: through the constant magnetic potential offset DJX, the overall potential change of the pipeline under constant magnetic conditions can be provided. Since the potential offset is an important indicator for assessing corrosion risk, the corrosion rate of the pipeline can be more accurately predicted by analyzing the overall potential change. When DJX≥100mV, it indicates that the potential offset exceeds the safety standard and the corrosion rate is fast, indicating that DC discharge protection or other protective measures need to be taken.

[0036] The beneficial effects of the present invention are as follows: the method of the present invention can effectively identify and quantify the degree of DC stray current interference on oil and gas pipelines by acquiring the potential information of the pipeline and the surrounding soil, calculating the potential deviation, screening out the potential nuclear display pipelines affected by interference, and performing constant magnetic potential analysis and corrosion rate evaluation on them, accurately analyzing the pipeline corrosion risk, and providing better stray current interference evaluation.

[0037] To achieve the above-mentioned purpose, the second aspect of the present invention also proposes a DC stray current corrosion evaluation system for oil and gas pipelines, wherein the DC stray current corrosion evaluation system for oil and gas pipelines comprises: a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps in a DC stray current corrosion evaluation method for oil and gas pipelines when executing the computer program, and the DC stray current corrosion evaluation system for oil and gas pipelines runs on desktop computers, notebooks, PDAs, and computing devices in cloud data centers.

[0038] The DC stray current corrosion evaluation system for oil and gas pipelines implements the DC stray current corrosion evaluation method for oil and gas pipelines, which can reflect the impact of the dynamic environment on the pipeline status in real time and accurately and comprehensively evaluate the current interference of the oil and gas pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Shown is a flow chart of a DC stray current corrosion evaluation method for oil and gas pipelines;

[0040] Figure 2 Shown is the structural diagram of the DC stray current corrosion evaluation system for oil and gas pipelines. DETAILED DESCRIPTION

[0041] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0042] Figure 1 Shown is a flow chart of a DC stray current corrosion evaluation method for oil and gas pipelines.

[0043] Reference Figure 1 The present invention provides a DC stray current corrosion evaluation method for oil and gas pipelines, the method comprising the following steps:

[0044] S100, obtaining the potential of the pipeline and the potential of the soil surface around the pipeline;

[0045] S200, calculating the pipeline potential deviation according to the pipeline potential and the potential of the soil surface around the pipeline;

[0046] S300, screening out the potential core display pipeline according to the pipeline potential deviation;

[0047] S400, performing a constant magnetic potential analysis on the potential nuclear display pipeline to obtain a constant magnetic potential offset;

[0048] S500, current disturbance evaluation by constant magnetopotential shift.

[0049] The evaluation method according to the embodiment of the present invention can reflect the impact of the dynamic environment on the pipeline status in real time, and accurately and comprehensively perform current interference evaluation on the oil and gas pipeline.

[0050] Since traditional potential measurements are usually concentrated at specific locations on the pipeline, such as key nodes or areas prone to corrosion (such as pipeline joints, near valves, etc.), while ignoring the potential conditions of other parts, this limitation leads to large errors in the potential status of the entire pipeline system.

[0051] Further, in order to solve the above problem, the method for obtaining the potential size of the pipeline and the potential size of the soil surface around the pipeline in step S100 includes: obtaining the potential size of the pipeline in each distance interval L by a potentiometer, wherein the distance interval L is set to [1, 50] meters; ISO(Li) is recorded as the potential size in the i-th distance interval Li of the pipeline, and LIS(Li) is recorded as the potential size of the soil surface around the i-th distance interval Li of the pipeline, wherein Li=[(i-1)*L, i*L], i=1, 2, ..., H, H∈[5, 100], i is the distance interval sequence number, the median of each potential size in all ISO(Li) is recorded as ISM, and the median of each potential size in all LIS(Li) is recorded as LIM;

[0052] By setting multiple distance intervals around the pipeline and using a potentiometer to fully obtain the potential information of the pipeline potential and the surrounding soil surface, the limitation of the potential measurement of stray current interference evaluation in the "DC stray current corrosion evaluation method for high-strength steel for oil and gas pipelines under stress conditions" with Chinese patent publication number CN104122196A is usually concentrated in specific locations, key nodes or areas prone to corrosion of the pipeline. This step can not only capture the potential changes of the pipeline at different locations, but also reflect the impact of the dynamic environment on the pipeline state in real time, and reduce the impact of individual outliers. The pipeline potential and soil potential can reveal the degree of DC stray current interference, providing a solid data foundation for subsequent corrosion risk assessment and protection measures, thereby significantly enhancing the safety and maintenance efficiency of oil and gas pipelines.

[0053] Further, in step S200, calculating the pipeline potential deviation according to the pipeline potential and the potential of the soil surface around the pipeline includes:

[0054] Let D(Li) be the pipeline potential deviation within the i-th distance interval Li of the pipeline, where D(Li) is the difference between ISO(Li) and LIS(Li); create an empty sequence and record it as the potential deviation sequence DK, import all D(Li) into the potential deviation sequence, and record the average value in the potential deviation sequence as DM;

[0055] The pipeline potential deviation is the deviation between the pipeline potential and the soil potential, which can quantify the potential state of the pipeline and accurately evaluate the degree of current interference. This quantification process is the basis for subsequent corrosion risk assessment. A large value of D(Li) indicates that the pipeline is subject to strong DC stray current interference; the potential stability of the entire pipeline system can be judged by the average value of the potential deviation DM.

[0056] Further, in step S300, the potential core display pipeline is screened out according to the pipeline potential deviation, including:

[0057] S301, calculating the standard deviation of all pipeline potential deviations in the potential deviation sequence DK, classifying the pipeline potential deviations based on the standard deviations, and obtaining a first pipeline potential deviation range, a second pipeline potential deviation range, and a third pipeline potential deviation range;

[0058] The specific method is as follows: calculate the standard deviation of all pipeline potential deviations in the potential deviation sequence DK, and classify the potential deviation sequence internally by the standard deviation of all pipeline potential deviations in the potential deviation sequence DK; record the value of DM minus the standard deviation as DG, and the value of DM plus the standard deviation as DP, classify the pipeline potential deviations in the potential deviation sequence DK that are less than or equal to DG into the first pipeline potential deviation range Dn1; classify the pipeline potential deviations in the potential deviation sequence DK that are greater than DG and less than DP into the second pipeline potential deviation range Dn2; classify the pipeline potential deviations in the potential deviation sequence DK that are greater than or equal to DP into the third pipeline potential deviation range Dn3;

[0059] The intervals of the first pipeline potential deviation range Dn1, the second pipeline potential deviation range Dn2, and the third pipeline potential deviation range Dn3 are respectively recorded as [N, K1], [K2, Y1], and [Y2, MX], where the interval [N, K1] represents the first pipeline potential deviation range Dn1, where N is the minimum value in the potential deviation sequence DK, and K1 is the value closest to DG among all pipeline potential deviations less than or equal to DG in the potential deviation sequence DK. The interval [K2, Y1] represents the second pipeline potential deviation range Dn2, where K2 is the value closest to DG among all pipeline potential deviations greater than DG in the potential deviation sequence DK, and Y1 is the value closest to DP among all pipeline potential deviations less than DP in the potential deviation sequence DK. The interval [Y2, MX] represents the third pipeline potential deviation range Dn3, where Y2 is the value closest to DP among all pipeline potential deviations greater than or equal to DP in the potential deviation sequence DK, and MX is the maximum value in the potential deviation sequence DK;

[0060] S302, calculating a first potential deviation boundary MYa and a second potential deviation boundary MYb through the first pipeline potential deviation range Dn1, the second pipeline potential deviation range Dn2, and the third pipeline potential deviation range Dn3;

[0061] The pipeline potential deviation is divided into different ranges, and the core potential deviation is further distinguished and extracted by setting the first potential deviation boundary MYa and the second potential deviation boundary MYb. This multi-dimensional classification not only simplifies the analysis process, but also can finely distinguish the potential state, which is helpful to formulate subsequent corrosion risk management measures in a targeted manner.

[0062] S303, according to the boundary values ​​of the first potential deviation boundary MYa and the second potential deviation boundary MYb, the potential deviation data between the two boundary values ​​is extracted and recorded as the core potential deviation DK (Lj), and the pipeline interval corresponding to the core potential deviation DK (Lj) is marked as the potential core display pipeline;

[0063] The first potential deviation boundary MYa is the maximum value K1 in the first pipeline potential deviation range Dn1 minus the minimum potential deviation range difference, wherein the minimum potential deviation range difference is the product of K2 and the potential deviation stable balance ratio, wherein the potential deviation stable balance ratio is the ratio of K1×ISM to K2×LIM; the second potential deviation boundary MYb is the maximum value K1 in the first pipeline potential deviation range Dn1 plus the maximum potential deviation range difference, wherein the maximum potential deviation range difference is the product of K2 and the potential deviation abnormal balance ratio, wherein the potential deviation abnormal balance ratio is the ratio of Y1×ISM to (Y2+Y1)×LIM;

[0064] Extract all D (Li) between the first potential deviation boundary MYa and the second potential deviation boundary MYb, and record them as core potential deviation DK (Lj), where j is the pipeline distance interval number between the first potential deviation boundary MYa and the second potential deviation boundary MYb of the pipeline potential deviation, and record the pipeline corresponding to DK (Lj) as the potential core display pipeline;

[0065] The potential core display pipeline is a pipeline section that has been screened and identified as being significantly interfered by DC stray current. The potential core display pipeline, as a whole, represents the pipeline section where the potential state is significantly deviated from the normal level and has a higher risk of interference, highlighting those pipelines that show abnormal potential changes.

[0066] The beneficial effects of this step are: dividing the pipeline potential deviation into different ranges, and further distinguishing and extracting the core potential deviation through the first potential deviation boundary MYa and the second potential deviation boundary MYb; this multi-dimensional classification not only simplifies the analysis process, but also can finely distinguish the potential state, which is helpful to formulate subsequent corrosion risk management measures in a targeted manner, and by screening the potential core display pipeline, it optimizes the allocation and use of monitoring resources, avoids single-type monitoring of the entire pipeline, saves cost and time, and improves monitoring efficiency and data processing speed.

[0067] Furthermore, in step S400, the method of performing constant magnetic potential analysis on the potential core display pipeline to obtain the constant magnetic potential offset includes:

[0068] The average magnetic field strength and potential offset of the potential core display pipeline in each time interval T are obtained by the Hall sensor, wherein the average magnetic field strength is the average value of all instantaneous magnetic field strengths in units of seconds in the time interval, wherein the time interval T is set to [0.5, 5] seconds; KMP(Tr) is denoted as the total magnetic field strength received by the potential core display pipeline in Tr, and DJMY(Tr, Lj) is denoted as the potential offset of the potential core display pipeline with serial number j in Tr, wherein Tr=[(r-1)*T, r*T], r=1, 2, ..., G, G∈[5, 100]; the minimum value among each KMP(Tr) is obtained and recorded as KMP(Tz), and Tz is recorded as the constant magnetic time, z∈[1, H];

[0069] Further, in step S500, the corrosion rate is evaluated by constant magnetic potential shift;

[0070] The average value of each DJMY(Tz, Lj) is recorded as the constant magnetic potential offset DJX. The interference degree is evaluated by DJX. When the constant magnetic potential offset DJX≥100mv, DC discharge protection or other protective measures need to be taken.

[0071] The beneficial effect of this step is: through the constant magnetic potential offset DJX, the overall potential change of the pipeline under constant magnetic conditions can be provided. Since the potential offset is an important indicator for assessing corrosion risk, the corrosion rate of the pipeline can be more accurately predicted by analyzing the overall potential change. When DJX≥100mV, it indicates that the potential offset exceeds the safety standard and the corrosion rate is fast, indicating that DC discharge protection or other protective measures need to be taken.

[0072] The beneficial effects of the present invention are as follows: the method of the present invention can effectively identify and quantify the degree of DC stray current interference on oil and gas pipelines by acquiring the potential information of the pipeline and the surrounding soil, calculating the potential deviation, screening out the potential nuclear display pipelines affected by interference, and performing constant magnetic potential analysis and corrosion rate evaluation on them, accurately analyzing the pipeline corrosion risk, and providing better stray current interference evaluation.

[0073] Figure 2 Shown is the structural diagram of the DC stray current corrosion evaluation system for oil and gas pipelines.

[0074] Reference Figure 2The present invention also proposes a DC stray current corrosion evaluation system 20 for oil and gas pipelines. The DC stray current corrosion evaluation system 20 for oil and gas pipelines includes: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps in a DC stray current corrosion evaluation method for oil and gas pipelines are implemented. The DC stray current corrosion evaluation system 20 for oil and gas pipelines runs on a desktop computer, a notebook, a PDA, and a computing device in a cloud data center.

[0075] The evaluation system comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to run in the following units of the evaluation system:

[0076] The acquisition unit 21 is used to obtain the potential of the pipeline and the potential of the soil surface around the pipeline;

[0077] A calculation unit 22, used for calculating the pipeline potential deviation according to the pipeline potential and the potential of the soil surface around the pipeline;

[0078] A screening unit 23, used to screen out the potential core display pipeline according to the pipeline potential deviation;

[0079] An analysis unit 24 is used to perform a constant magnetic potential analysis on the potential nuclear display pipeline to obtain a constant magnetic potential offset;

[0080] The display unit 25 is used for current disturbance evaluation by means of constant magnetic potential shift.

[0081] The DC stray current corrosion evaluation system for oil and gas pipelines can be run in computing devices such as desktop computers, notebooks, PDAs, and cloud servers. The DC stray current corrosion evaluation system for oil and gas pipelines can include, but is not limited to, processors and memories. Those skilled in the art will understand that the example is only an example of a DC stray current corrosion evaluation system 20 for oil and gas pipelines, and does not constitute a limitation on a DC stray current corrosion evaluation system 20 for oil and gas pipelines. It can include more or fewer components than the example, or combine certain components, or different components. For example, the DC stray current corrosion evaluation system for oil and gas pipelines can also include input and output devices, network access devices, buses, etc.

[0082] By executing the DC stray current corrosion evaluation method for oil and gas pipelines through the DC stray current corrosion evaluation system 20 for oil and gas pipelines, the impact of the dynamic environment on the pipeline state can be reflected in real time, and the current interference evaluation of the oil and gas pipeline can be performed accurately and comprehensively.

[0083] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and editable read-only memory (EMYROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0084] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (MYGA), a field programmable gate array (FMYGA), etc.

[0085] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0086] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0087] In addition, the terms "first", "second", etc. used in the embodiments of the present invention are only used for descriptive purposes and should not be understood as indicating or implying relative importance, or implicitly indicating the number of technical features indicated in the present embodiment. Therefore, the features defined by the terms "first", "second", etc. in the embodiments of the present invention can explicitly or implicitly indicate that the embodiment includes at least one of the features. In the description of the present invention, the word "multiple" means at least two or two or more, such as two, three, four, etc., unless otherwise clearly and specifically defined in the embodiments.

[0088] In the present invention, unless otherwise clearly specified or limited in the embodiments, the terms "installed", "connected", "connected" and "fixed" etc. in the embodiments should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integrated connection. It can be understood that it can also be a mechanical connection, an electrical connection, etc.; of course, it can also be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements, or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific implementation situation.

[0089] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0090] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A DC stray current corrosion evaluation method for oil and gas pipelines, characterized in that: The method comprises the following steps: S100, obtaining the potential of the pipeline and the potential of the soil surface around the pipeline; wherein step S100 includes: obtaining the potential of the pipeline in each distance interval L by a potentiometer, wherein the distance interval L is set to [1, 50] meters; ISO(Li) is denoted as the potential of the pipeline in the i-th distance interval Li, and LIS(Li) is denoted as the potential of the soil surface around the pipeline in the i-th distance interval Li, wherein Li=[(i-1)*L, i*L], i=1, 2, ..., H, H∈[5, 100], i is the distance interval serial number, the median of each potential in all ISO(Li) is denoted as ISM, and the median of each potential in all LIS(Li) is denoted as LIM; S200, calculating the pipeline potential deviation by the potential of the pipeline and the potential of the soil surface around the pipeline; wherein step S200 includes: recording D(Li) as the pipeline potential deviation within the i-th distance interval Li of the pipeline, wherein D(Li) is the difference between ISO(Li) and LIS(Li); creating an empty sequence and recording it as a potential deviation sequence DK, importing all D(Li) into the potential deviation sequence, and recording the average value in the potential deviation sequence as DM; S300, screening out the potential core display pipeline according to the pipeline potential deviation; S301, calculate the standard deviation of all pipeline potential deviations in the potential deviation sequence DK, classify the pipeline potential deviations based on this, and obtain the first pipeline potential deviation range, the second pipeline potential deviation range, and the third pipeline potential deviation range; calculate the standard deviation of all pipeline potential deviations in the potential deviation sequence DK, and classify the potential deviation sequence internally by the standard deviation of all pipeline potential deviations in the potential deviation sequence DK; record the value of DM minus the standard deviation as DG, and the value of DM plus the standard deviation as DP, and classify the pipeline potential deviations in the potential deviation sequence DK that are less than or equal to DG into the first pipeline potential deviation range Dn1; classify the pipeline potential deviations in the potential deviation sequence DK that are greater than DG and less than DP into the second pipeline potential deviation range Dn2; classify the pipeline potential deviations in the potential deviation sequence DK that are greater than or equal to DP into the third pipeline potential deviation range Dn3; classify the first pipeline potential deviation range Dn1, the second pipeline potential deviation range Dn2, and the third pipeline potential deviation range Dn3 into the third pipeline potential deviation range Dn4; classify the first pipeline potential deviation range Dn1, the second pipeline potential deviation range Dn5, and the third pipeline potential deviation range Dn6. The intervals of the difference range Dn2 and the third pipeline potential deviation range Dn3 are respectively recorded as [N, K1], [K2, Y1], and [Y2, MX], wherein the interval [N, K1] represents the first pipeline potential deviation range Dn1, wherein N is the minimum value in the potential deviation sequence DK, and K1 is the value closest to DG among all pipeline potential deviations less than or equal to DG in the potential deviation sequence DK; the interval [K2, Y1] represents the second pipeline potential deviation range Dn2, wherein K2 is the value closest to DG among all pipeline potential deviations greater than DG in the potential deviation sequence DK, and Y1 is the value closest to DP among all pipeline potential deviations less than DP in the potential deviation sequence DK; the interval [Y2, MX] represents the third pipeline potential deviation range Dn3, wherein Y2 is the value closest to DP among all pipeline potential deviations greater than or equal to DP in the potential deviation sequence DK, and MX is the maximum value in the potential deviation sequence DK; S302, calculating a first potential deviation boundary and a second potential deviation boundary through the first pipeline potential deviation range, the second pipeline potential deviation range, and the third pipeline potential deviation range; wherein the first potential deviation boundary MYa is the maximum value K1 in the first pipeline potential deviation range Dn1 minus the minimum potential deviation range difference, wherein the minimum potential deviation range difference is the product of K2 and the potential deviation stable balance ratio, wherein the potential deviation stable balance ratio is the ratio of K1×ISM to K2×LIM; wherein the second potential deviation boundary MYb is the maximum value K1 in the first pipeline potential deviation range Dn1 plus the maximum potential deviation range difference, wherein the maximum potential deviation range difference is the product of K2 and the potential deviation abnormal balance ratio, wherein the potential deviation abnormal balance ratio is the ratio of Y1×ISM to (Y2+Y1)×LIM; S303, according to the boundary values ​​of the first potential deviation boundary and the second potential deviation boundary, the potential deviation data between the two boundary values ​​is extracted and recorded as the core potential deviation, and the pipeline interval corresponding to the core potential deviation is marked as the potential core display pipeline; wherein, all D (Li) between the two boundary values ​​belonging to the first potential deviation boundary MYa and the second potential deviation boundary MYb are extracted and recorded as the core potential deviation DK (Lj), wherein j is the pipeline distance interval sequence number between the first potential deviation boundary MYa and the second potential deviation boundary MYb of the pipeline potential deviation, and the pipeline corresponding to DK (Lj) is recorded as the potential core display pipeline; S400, perform constant magnetic potential analysis on the potential core display pipeline to obtain constant magnetic potential offset; wherein step S400 includes: obtaining the average magnetic field strength and potential offset of the potential core display pipeline in each time interval T through a Hall sensor, wherein the average magnetic field strength is the average value of all instantaneous magnetic field strengths in units of seconds in the time interval, wherein the time interval T is set to [0.5, 5] seconds; denoting KMP(Tr) as the total magnetic field strength received by the potential core display pipeline in Tr, denoting DJMY(Tr, Lj) as the potential offset of the potential core display pipeline with serial number j in Tr, wherein Tr=[(r-1)*T, r*T], r=1, 2, ..., H, H∈[5, 100]; obtaining the minimum value of each KMP(Tr) as KMP(Tz), denoting Tz as the constant magnetic time, z∈[1, H]; S500, current interference is evaluated by constant magnetic potential offset; wherein, step S500 includes: recording the average value of each DJMY (Tz, Lj) as the constant magnetic potential offset DJX, and evaluating the interference degree by DJX, when the constant magnetic potential offset DJX ≥ 100mv, the corrosion rate is evaluated to be high, otherwise the corrosion rate is low; if the corrosion rate is evaluated to be high, DC discharge protection measures need to be taken.

2. A DC stray current corrosion evaluation system for oil and gas pipelines, characterized in that: The DC stray current corrosion evaluation system for oil and gas pipelines includes: a processor, a memory, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps in the DC stray current corrosion evaluation method for oil and gas pipelines in claim 1 are implemented.

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