A digital and intelligent comprehensive evaluation method and system for the effectiveness of submarine pipeline anticorrosion agents

Abstract

The present invention relates to the field of data processing technology, and proposes a digital, comprehensive evaluation method and system for the effectiveness of submarine pipeline anticorrosion agents. The method comprises: obtaining a deposition influence based on the difference in corrosion thickness between a middle sample and a bottom sample; obtaining a velocity-deposition reference index based on the negative correlation between the deposition influence and the corrosion thickness, and thereby obtaining an analytical reference level for the bottom sample; obtaining a velocity correlation based on the velocity-deposition reference index; obtaining a velocity-sediment correlation function based on the velocity correlation; obtaining a deposition-velocity-corrosion ratio based on the overall velocity level and corrosion thickness of the middle sample and the deposition influence and corrosion thickness of the bottom sample; and obtaining a corrosion inhibitor effectiveness test result based on the deposition-velocity-corrosion ratio. The present invention analyzes the impact of sediment on pipeline corrosion through the deposition-velocity-corrosion ratio, thereby improving the accuracy of corrosion rate measurement and increasing the credibility of corrosion inhibitor effectiveness testing.

Description

Technical Field

[0001] The present invention relates to the field of data processing technology, and in particular to a digital and intelligent comprehensive evaluation method and system for the effectiveness of submarine pipeline anti-corrosion agents. Background Art

[0002] Subsea oil pipelines are critical infrastructure for transporting crude oil in marine environments. These pipelines are typically laid on the seabed or buried in seafloor sediments to mitigate the effects of currents and external corrosion. They are typically constructed from high-strength steel and utilize specialized anti-corrosion coatings and cathodic protection technologies to extend their service life and ensure safe transportation. Subsea pipelines enable efficient and continuous oil transportation, reducing the risk of leaks and environmental pollution compared to tanker transportation while also improving the stability of energy supply.

[0003] Crude oil contains corrosive components such as hydrogen sulfide, carbon dioxide, and chlorides. These components, when combined with water, create an acidic environment, leading to acidic corrosion or pitting corrosion in pipelines, shortening their service life. To prevent corrosion of the inner walls of pipelines, submarine pipelines used to transport oil require internal corrosion protection. By injecting corrosion inhibitors such as corrosion inhibitors, deoxidizers, or biocides, the effects of corrosive media on the pipe walls can be reduced, extending pipeline life, improving transportation efficiency, and reducing maintenance and replacement costs.

[0004] Because submarine pipelines are exposed to the corrosive media in crude oil for extended periods, corrosion inhibitors must possess excellent chemical stability, durability, and compatibility with pipeline materials. Factory inspections verify the inhibitor's corrosion inhibition effectiveness, resistance to microbial corrosion, and performance under high-temperature and high-pressure conditions, ensuring it will not decompose, lose effectiveness, or produce side effects during long-term use.

[0005] Currently, the blank corrosion rate and the added corrosion rate are mainly obtained in the laboratory scenario through the high-temperature and high-pressure dynamic method, and the effectiveness of the corrosion inhibitor is judged based on the measurement results of the blank corrosion rate and the added corrosion rate. However, the anti-corrosion film of submarine pipelines may be damaged due to oil erosion and sediment coverage. It is difficult for the laboratory to simulate the corrosive effect of sediments during the high-temperature and high-pressure dynamic method, resulting in inaccurate laboratory corrosion rate measurement results. Summary of the Invention

[0006] The present invention provides a digital and intelligent comprehensive evaluation method and system for the effectiveness of submarine pipeline anticorrosion agents to solve the problem of inaccurate corrosion rate measurement results in existing laboratories. The technical solutions adopted are as follows:

[0007] The present invention proposes a digital and intelligent comprehensive evaluation method for the effectiveness of submarine pipeline anticorrosion agents, which includes the following steps:

[0008] Obtain the overall flow velocity level and corrosion thickness of each middle specimen and each bottom specimen at each thickness sampling moment;

[0009] According to the difference in corrosion thickness between the middle sample and the bottom sample at similar overall flow rate levels, the deposition influence of each bottom sample at each thickness sampling time was obtained;

[0010] According to the negative correlation between the deposition influence degree and the corrosion thickness of the bottom sample at each thickness sampling moment, the flow velocity deposition reference index of each bottom sample at each thickness sampling moment is obtained; according to the flow velocity deposition reference index of the bottom sample at all thickness sampling moments, the analysis reference degree of each bottom sample is obtained; and the flow velocity correlation degree of each bottom sample at each thickness sampling moment is obtained in combination with the flow velocity deposition reference index;

[0011] The velocity-sediment correlation function was obtained based on the velocity correlation degree of the bottom sample at the thickness sampling time. The deposition-velocity-corrosion ratio of each flow velocity was obtained by combining the overall velocity level and corrosion thickness of the middle sample at each thickness sampling time, as well as the deposition influence and corrosion thickness of the bottom sample at each thickness sampling time.

[0012] According to the deposition flow rate corrosion ratio of each flow rate, the anti-corrosion effectiveness test results of the corrosion inhibitor are obtained.

[0013] Furthermore, the deposition influence of each bottom sample at each thickness sampling moment is obtained based on the difference in corrosion thickness between the middle sample and the bottom sample at similar overall flow rate levels, including the following specific methods:

[0014] According to the similarity of the overall flow velocity levels of the bottom sample and the middle sample at the thickness sampling time, the closeness of the flow velocity of each bottom sample and each middle sample at each thickness sampling time is obtained;

[0015] No. The bottom specimen is The calculation method of the deposition influence at each thickness sampling moment is:

[0016] ;

[0017] Where, For the The bottom specimen is Deposition influence at each thickness sampling moment; For the The bottom specimen and The middle sample is in the The closeness of the flow velocity at each thickness sampling moment; For the The bottom specimen is The corrosion thickness at each thickness sampling moment; For the The middle sample is in the The corrosion thickness at each thickness sampling moment; is the number of middle specimens; is the absolute value function.

[0018] Furthermore, the similarity of the overall flow velocity levels of the bottom sample and the middle sample at the thickness sampling time is obtained, and the flow velocity closeness of each bottom sample and each middle sample at each thickness sampling time is obtained, including the specific method of:

[0019] For any bottom sample and any middle sample, the inverse proportional normalization result of the absolute value of the difference between the overall flow velocity levels of the bottom sample and the middle sample at any thickness sampling moment is recorded as the degree of closeness between the flow velocities of the bottom sample and the middle sample at the thickness sampling moment.

[0020] Furthermore, the flow velocity deposition reference index of each bottom sample at each thickness sampling moment is obtained based on the negative correlation between the deposition influence of the bottom sample at each thickness sampling moment and the corrosion thickness, including the specific method of:

[0021] No. The bottom specimen is The thickness sampling time and the The bottom specimen is The calculation method of the sedimentation velocity correlation index at each thickness sampling moment is:

[0022] ;

[0023] Where, For the The bottom specimen is The thickness sampling time and the The bottom specimen is Sediment velocity correlation index at each thickness sampling moment; For the The bottom specimen is Deposition influence at each thickness sampling moment; For the The bottom specimen is Deposition influence at each thickness sampling moment; is the maximum value of the sedimentation influence of all bottom samples at all thickness sampling moments; It is the maximum value of the overall flow velocity level of all bottom specimens at all thickness sampling moments; For the The bottom specimen is The overall flow velocity level at each thickness sampling moment; For the The bottom specimen is The overall flow velocity level at each thickness sampling moment; is the rounding symbol; is the absolute value function;

[0024] For any bottom sample at any thickness sampling time, the sum of the deposition velocity correlation index of the bottom sample at the thickness sampling time and all bottom samples at all thickness sampling times is recorded as the velocity deposition reference index of the bottom sample at the thickness sampling time.

[0025] Furthermore, the analysis reference degree of each bottom sample is obtained according to the flow rate deposition reference index of the bottom sample at all thickness sampling moments, including the specific method of:

[0026] For any bottom sample, the linear normalization result of the product of the mean and variance of the flow velocity deposition reference index of the bottom sample at all thickness sampling moments is recorded as the analytical reference degree of the bottom sample.

[0027] Furthermore, the specific method for obtaining the flow velocity correlation degree of each bottom sample at each thickness sampling moment includes:

[0028] The linear normalization result of the product of the velocity deposition reference index of any bottom sample at any thickness sampling moment and the analysis reference degree of the bottom sample is recorded as the velocity correlation degree of the bottom sample at the thickness sampling moment.

[0029] Furthermore, the velocity-sediment correlation function is obtained according to the velocity correlation degree of the bottom sample at the thickness sampling time, including the specific method of:

[0030] A two-dimensional rectangular coordinate system was established with the overall flow velocity level as the horizontal coordinate and the sedimentation influence as the vertical coordinate. The data of all bottom samples at each thickness sampling time were mapped to the two-dimensional rectangular coordinate system to obtain several data points in the two-dimensional rectangular coordinate system. The flow velocity correlation degree of each bottom sample at each thickness sampling time was used as the fitting weight of the corresponding data point. The least squares method was used to perform curve fitting on all data points to obtain the flow velocity-sediment correlation function.

[0031] Furthermore, the specific method of obtaining the deposition flow rate corrosion ratio of each flow rate includes:

[0032] The velocity-corrosion correlation function was obtained based on the overall velocity level and corrosion thickness of the middle specimen at each thickness sampling moment.

[0033] The deposition-corrosion correlation function is obtained based on the deposition influence and corrosion thickness of the bottom sample at each thickness sampling moment.

[0034] Substituting the function value of the velocity-sediment correlation function into the independent variable of the deposition-corrosion correlation function, the velocity-sedimentation-corrosion correlation function is obtained;

[0035] For any flow rate, the ratio of the corresponding corrosion thickness of the flow rate in the flow rate-deposition-corrosion correlation function to the corresponding corrosion thickness of the flow rate in the deposition-corrosion correlation function is recorded as the deposition-flow rate-corrosion ratio of the flow rate.

[0036] Furthermore, the anti-corrosion effectiveness test result of the corrosion inhibitor is obtained according to the deposition flow rate corrosion ratio of each flow rate, including the specific method of:

[0037] Obtain blank corrosion rates at several flow rates;

[0038] For any flow rate, the product of the blank corrosion rate at that flow rate and the deposition flow rate corrosion ratio at that flow rate is recorded as the blank deposition corrosion rate at that flow rate; the maximum value of the blank corrosion rate at that flow rate and the blank deposition corrosion rate is recorded as the actual blank corrosion rate at that flow rate;

[0039] Obtain the dosing corrosion ratio at each flow rate; obtain the dosing corrosion rate at several flow rates;

[0040] For any flow rate, the product of the chemical corrosion rate at that flow rate and the chemical corrosion ratio at that flow rate is recorded as the chemical deposition corrosion rate at that flow rate; the maximum value of the chemical corrosion rate at that flow rate and the chemical deposition corrosion rate is recorded as the actual chemical corrosion rate at that flow rate;

[0041] An evaluation result of the effectiveness of the submarine pipeline corrosion inhibitor is obtained according to the actual blank corrosion rate and the actual added corrosion rate.

[0042] The present invention also proposes a digital comprehensive evaluation system for the effectiveness of submarine pipeline anti-corrosion agents. The system includes a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of the above method are implemented.

[0043] The beneficial effects of the present invention are as follows: during the transportation of oil in submarine pipelines, when the flow rate of oil is slow, sediment will exist at the bottom of the pipeline due to gravity, and the sediment will cause corrosion to the submarine pipeline. The present invention obtains the sediment influence of each bottom sample at each thickness sampling moment through the difference in corrosion thickness between the middle sample and the bottom sample at a similar overall flow rate level, and analyzes the degree to which each bottom sample is affected by the sediment; when analyzing the changing relationship between flow rate and sediment, it is necessary to exclude the deviation of individual samples caused by slight differences in local geometric shape or installation position. The present invention obtains the flow rate correlation degree by obtaining the flow rate deposition reference index and the analysis reference degree, and then determines the data correlation between the flow rate and sediment of each bottom sample at each thickness sampling moment; during the transportation of oil, since the corrosion reaction of the metal surface is accelerated when the oil flows at a high speed, the sediment when the oil flows at a slow speed will accelerate the corrosion reaction of the submarine pipeline. The present invention obtains the deposition-flow-corrosion ratio at each flow rate to determine the corrosion effect of the sediment and flow rate on the submarine pipeline at each flow rate. Thus, the present invention obtains the anti-corrosion effectiveness test result of the corrosion inhibitor through the deposition flow rate corrosion ratio, improves the accuracy of the corrosion rate measurement, and increases the credibility of the corrosion inhibitor effectiveness test. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 A schematic flow chart of a digital comprehensive evaluation method for the effectiveness of submarine pipeline anti-corrosion agents provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0047] See also Figure 1 , which shows a flow chart of a digital and intelligent comprehensive evaluation method for the effectiveness of submarine pipeline anticorrosion agents provided by one embodiment of the present invention. The method includes the following steps:

[0048] Step S001: Obtain the overall flow velocity level and corrosion thickness of each middle sample and each bottom sample at each thickness sampling moment.

[0049] It should be noted that the effectiveness of submarine pipeline corrosion inhibitors is mainly reflected in the change in submarine pipeline corrosion rate before and after addition of the agent. The corrosion rate of submarine pipelines is mainly affected by oil flow rate and sediment. Therefore, metal samples are arranged in the test pipeline to obtain flow rate data and corrosion data to determine the impact of oil flow rate and sediment on corrosion rate.

[0050] Specifically, a closed piping system is built in the laboratory, which can control the flow rate of the fluid; the inner wall of the piping system is divided into top, middle and bottom parts, and several metal samples are set in the middle and bottom parts of the inner wall of the pipe respectively. The specific arrangement of the metal samples is as follows: An installation point is set up every meter, and a metal sample with the same material as the actual pipeline is installed at each installation point. The size and surface treatment of the sample must be consistent with the actual pipeline; To preset the installation distance, this embodiment uses Take this as an example to describe;

[0051] The metal sample located in the middle of the inner wall of the pipe is recorded as the middle sample; the metal sample located at the bottom of the inner wall of the pipe is recorded as the bottom sample;

[0052] An ultrasonic sensor is installed on each metal sample to measure the thickness of the metal sample; a flow meter is installed near each metal sample to obtain the flow rate of the fluid;

[0053] Adding oil to the piping system;

[0054] Before the test process begins, the thickness of each metal sample is first tested.

[0055] At the beginning of the test, the oil flow rate was controlled at 0.1 m / s, and the flow rate was increased by 0.6 m / s every day until the oil flow rate was greater than 6 m / s, and then the test was stopped;

[0056] After the test begins, for any metal sample, use a flow meter near the metal sample to collect the oil flow rate of the metal sample once every 10 seconds as a flow rate sampling moment, and obtain the oil flow rate of the metal sample at each flow rate sampling moment;

[0057] Using an ultrasonic sensor on the metal sample to collect the sample thickness of the metal sample once every other day as a thickness sampling moment, to obtain the sample thickness of the metal sample at each thickness sampling moment;

[0058] For any metal sample and any thickness sampling moment, the average of the oil flow rates of the metal sample at all flow rate sampling moments between the thickness sampling moment and the previous thickness sampling moment is recorded as the overall flow rate level of the metal sample at the thickness sampling moment;

[0059] For any metal sample and any thickness sampling time, the difference obtained by subtracting the sample thickness of the metal sample at the thickness sampling time from the sample thickness at the previous thickness sampling time is recorded as the corrosion thickness of the metal sample at the thickness sampling time.

[0060] Step S002: according to the difference in corrosion thickness between the middle sample and the bottom sample at similar overall flow rate levels, the deposition influence of each bottom sample at each thickness sampling moment is obtained.

[0061] It should be noted that during oil transportation, the middle of the pipeline is usually the area with the highest fluid velocity, and the flow velocity has a more significant scouring effect on the metal surface. Under turbulent conditions, high flow velocity will lead to an increase in corrosion rate. The main mechanisms include increasing the mass transfer rate of oxygen or corrosive ions and intensifying cathode or anodic reactions. However, due to the high flow velocity in the middle, it is not easy to form deposits, so corrosion is mainly caused by flow velocity. Due to gravity, the bottom of the pipeline is where deposits are most likely to accumulate. Low flow velocity areas often lead to local flow retention, so that deposits cannot be carried away by the fluid, forming an environment that is conducive to microbial corrosion and localized corrosion. The middle sample reflects the direct effect of flow velocity on corrosion, and the bottom sample reflects the combined effect of flow velocity and deposits. Therefore, combining the middle sample with the bottom sample can more comprehensively analyze the corrosion mechanism.

[0062] It's important to note that generally, deposit-covered pipe locations exhibit faster corrosion rates. This is because deposits create localized microenvironments on the metal surface, such as localized oxygen deficiency and concentration cell effects, which can induce or exacerbate pitting and crevice corrosion. Areas affected only by flow velocity generally exhibit primarily uniform corrosion, with rates typically lower than those of locally accelerated corrosion. At the same flow rate and exposure time, if the bottom specimen corrodes more severely than the middle specimen, this indicates the bottom specimen is affected by deposits. The greater the difference in corrosion severity, the greater the impact of deposits on the bottom specimen. During the test, the corrosion severity of the metal specimen is reflected in the thickness change of the specimen: the greater the thickness reduction, the higher the corrosion severity. When the overall flow velocity levels of the bottom and middle specimens at a given thickness are similar, it indicates that the two specimens are exposed to similar oil flow environments. In this case, the difference in thickness change between the two specimens more clearly reflects the impact of deposits on the corrosion rate.

[0063] Specifically, The bottom specimen and The middle sample is in the The calculation method for the closeness of the flow velocity at each thickness sampling moment is:

[0064] ;

[0065] Where, For the The bottom specimen and The middle sample is in the The closeness of the flow velocity at each thickness sampling moment; For the The middle sample is in the The overall flow velocity level at each thickness sampling moment; For the The bottom specimen is The overall flow velocity level at each thickness sampling moment; is the absolute value function; is an exponential function with a natural constant as its base.

[0066] It should be noted that for any middle sample and any bottom sample, if the flow velocities of the two metal samples at a certain thickness sampling time are similar, but the corrosion thickness of the bottom sample is greater than that of the middle sample, it means that the bottom sample is more affected by the sediment.

[0067] Specifically, The bottom specimen is The calculation method of the deposition influence at each thickness sampling moment is:

[0068] ;

[0069] Where, For the The bottom specimen is Deposition influence at each thickness sampling moment; For the The bottom specimen and The middle sample is in the The closeness of the flow velocity at each thickness sampling moment; For the The bottom specimen is The corrosion thickness at each thickness sampling moment; For the The middle sample is in the The corrosion thickness at each thickness sampling moment; is the number of middle specimens; is the absolute value function.

[0070] What needs to be explained is that The larger the The bottom specimen and The middle sample is in the From the thickness sampling moment to the The closer the time interval of the thickness sampling moments is to the degree of influence of the flow velocity, the As the size increases, The larger the The bottom specimen and Under the condition of similar flow rate influence, the middle samples The bottom specimen was more corroded. The more likely a bottom sample is to be affected by sediment.

[0071] Step S003: According to the negative correlation between the deposition influence of the bottom sample at each thickness sampling moment and the corrosion thickness, a velocity deposition reference index of each bottom sample at each thickness sampling moment is obtained; according to the velocity deposition reference index of the bottom sample at all thickness sampling moments, an analysis reference degree of each bottom sample is obtained; and in combination with the velocity deposition reference index, a velocity correlation degree of each bottom sample at each thickness sampling moment is obtained.

[0072] It should be noted that under high-speed flow conditions, the scouring effect of the fluid is significantly enhanced, which will accelerate the corrosion reaction on the metal surface. For example, by increasing the mass transfer rate of corrosive substances (such as water, CO2, and H2S), the metal will corrode more quickly. However, high flow rates also have a "cleaning" effect, which can effectively wash away the deposits and corrosion products formed on the metal surface, thereby reducing the concentration cell effect and pitting risk caused by local deposition. This dual effect indicates that high flow rates may accelerate corrosion by enhancing mass transfer, and may also slow down local corrosion by inhibiting the accumulation of deposits. Therefore, the corrosion rate does not simply increase with the increase in flow rate, but is regulated by the overall dynamic balance of the flow field.

[0073] It is important to further clarify that in order to determine the effects of flow rate and deposits on corrosion efficiency at different flow rates, the flow rate, while influencing corrosion efficiency, also affects the amount of deposits due to its "cleaning" effect. Therefore, the deposition effect of the metal sample to be analyzed must be high due to the slow flow rate, and the deposition effect is negatively correlated with the flow rate.

[0074] Specifically, The bottom specimen is The thickness sampling time and the The bottom specimen is The calculation method of the sedimentation velocity correlation index at each thickness sampling moment is:

[0075] ;

[0076] Where, For the The bottom specimen is The thickness sampling time and the The bottom specimen is Sediment velocity correlation index at each thickness sampling moment; For the The bottom specimen is Deposition influence at each thickness sampling moment; For the The bottom specimen is Deposition influence at each thickness sampling moment; is the maximum value of the sedimentation influence of all bottom samples at all thickness sampling moments; It is the maximum value of the overall flow velocity level of all bottom specimens at all thickness sampling moments; For the The bottom specimen is The overall flow velocity level at each thickness sampling moment; For the The bottom specimen is The overall flow velocity level at each thickness sampling moment; is the rounding symbol; is the absolute value function.

[0077] in, When it is 1, it means The bottom specimen is The thickness sampling time is greater than the The bottom specimen is The deposition at each thickness sampling moment has a great influence. When it is 0, it means The bottom specimen is The thickness sampling time is greater than the The bottom specimen is The influence of deposition at the thickness sampling moment is small. and Same number, indicating the The bottom specimen is The thickness sampling time and the The bottom specimen is The influence of sediment at the thickness sampling time is negatively correlated with the flow velocity, indicating that the The bottom specimen is The influence of sediments at the time of thickness sampling is compared. The bottom specimen is The deposition effect at each thickness sampling moment may be affected by the flow velocity.

[0078] It should be noted that the degree of influence of deposits on most metal specimens is negatively correlated with the flow velocity. The main reason is that the flow field environment in which most specimens are located is relatively uniform. That is, in areas with higher flow velocity, the shear force and scouring effect of the fluid are strong, which can effectively remove or prevent the accumulation of deposits and corrosion products on the metal surface; while in areas with lower flow velocity, the fluid kinetic energy is insufficient, and deposits are more likely to settle and accumulate. Therefore, most specimens will show this negative correlation under similar fluid conditions. Slight differences in local geometry or installation position may cause deviations in individual specimens, so it is necessary to judge the flow velocity deposition reference degree of each bottom specimen.

[0079] It should be further explained that the deposition velocity correlation index of any metal sample at any thickness sampling moment is relatively large compared with that of most metal samples at each thickness sampling moment, indicating that the deposition influence of the bottom sample at this thickness sampling moment is more likely to be affected by the flow velocity. Based on this, the flow velocity deposition reference index of each bottom sample at each thickness sampling moment is calculated.

[0080] Specifically, The bottom specimen is The calculation method of the velocity deposition reference index at each thickness sampling moment is:

[0081] ;

[0082] Where, For the The bottom specimen is The velocity deposition reference index at each thickness sampling moment; For the The bottom specimen is The thickness sampling time and the The bottom specimen is Sediment velocity correlation index at each thickness sampling moment; is the number of thickness sampling moments; is the number of bottom specimens.

[0083] It should be noted that for any bottom sample, the position of the bottom sample in the pipeline is fixed. Due to slight differences in local geometric shapes or installation positions, the correlation between flow velocity and sediment of some individual metal samples is low. Therefore, when the flow velocity deposition reference index of a bottom sample fluctuates greatly in time or is always in a low state, it means that the reference level of the bottom sample in analyzing the correlation between flow velocity and sediment is low.

[0084] Specifically, The analytical reference level of each bottom sample is calculated as follows:

[0085] ;

[0086] Where, For the The analytical reference level of each bottom sample; For the The mean value of the velocity deposition reference index of the bottom sample at all thickness sampling moments; For the The variance of the velocity deposition reference index of the bottom sample at all thickness sampling moments; is a linear normalization function, and the normalization object is all bottom samples. .

[0087] It should be noted that for any bottom sample at any thickness sampling time, if the analysis reference degree of the bottom sample is high, it means that the correlation between the flow velocity and the sediment is high due to the location of the bottom sample, and it can be used to analyze the correlation between the flow velocity and the sediment. When the flow velocity deposition reference index of the bottom sample at the thickness sampling time is high, it means that the correlation between the flow velocity and the sediment at the thickness sampling time is relatively high, so the flow velocity deposition reference index of each bottom sample at each thickness sampling time is obtained accordingly.

[0088] No. The bottom specimen is The calculation method of the flow velocity correlation degree at each thickness sampling moment is:

[0089] ;

[0090] Where, For the The bottom specimen is The degree of correlation between flow velocity at each thickness sampling moment; For the The bottom specimen is The velocity deposition reference index at each thickness sampling moment; For the The analytical reference level of each bottom sample; is a linear normalization function, and the normalization object is the thickness of all bottom samples at each sampling moment. .

[0091] Step S004: Obtain a velocity-sediment correlation function based on the velocity correlation of the bottom sample at the thickness sampling moment; and obtain the deposition-velocity-corrosion ratio of each flow velocity by combining the overall velocity level and corrosion thickness of the middle sample at each thickness sampling moment, as well as the deposition influence and corrosion thickness of the bottom sample at each thickness sampling moment.

[0092] It should be noted that when establishing the corresponding relationship between the flow velocity of the bottom sample and the sedimentation influence, the analysis is mainly based on the data with a higher degree of flow velocity correlation.

[0093] Specifically, a two-dimensional rectangular coordinate system is established with the overall flow velocity level as the horizontal coordinate and the sedimentation influence as the vertical coordinate, and the data of all bottom samples at each thickness sampling time are mapped to the two-dimensional rectangular coordinate system to obtain a number of data points in the two-dimensional rectangular coordinate system. The flow velocity correlation degree of each bottom sample at each thickness sampling time is used as the fitting weight of the corresponding data point, and the least squares method is used to perform curve fitting on all data points to obtain the flow velocity-sediment correlation function; wherein, the least squares method is a well-known technology, and the specific method will not be introduced here.

[0094] It should be noted that after analyzing the correlation between flow rate and deposition, it was found that in the bottom sample, flow rate and deposition each affect corrosion through different mechanisms. The flow rate directly affects the mass transfer rate of corrosive media (such as water, CO2, H2S, etc.) and the scouring effect on the protective film on the metal surface. High flow rate accelerates the contact between the medium and the metal, making the corrosion reaction more intense. At the same time, solid particles and corrosion products are easily deposited at the bottom due to gravity, and the deposits will form local closed areas on the metal surface, resulting in local concentration cell effects and insufficient oxygen supply, thereby inducing or aggravating local corrosion. Therefore, flow rate and deposition will have a corrosive effect on the bottom sample respectively.

[0095] It should be further explained that when analyzing the relationship between flow velocity and corrosion, since the middle sample is only affected by the flow velocity and not by the sediment, the relationship between flow velocity and corrosion can be constructed based on this.

[0096] Specifically, a two-dimensional rectangular coordinate system is established with the overall flow velocity level as the horizontal coordinate and the corrosion thickness as the vertical coordinate, and the data of all middle samples at each thickness sampling moment are mapped to the two-dimensional rectangular coordinate system to obtain a number of data points in the two-dimensional rectangular coordinate system. The least squares method is used to perform curve fitting on all data points to obtain the flow velocity-corrosion correlation function; wherein the least squares method is a well-known technology.

[0097] It should be noted that when analyzing the correlation between the influence of deposition and corrosion, the degree of direct contact between the metal surface and the fluid will be reduced after being covered by sediment, because the sediment forms a barrier, which makes the direct effects of flow rate on mass transfer, shear force, etc. on the metal surface relatively weakened, thereby reducing the impact of flow rate changes on the corrosion process. Therefore, the correlation between deposition and corrosion is mainly analyzed based on the bottom sample.

[0098] Specifically, a two-dimensional rectangular coordinate system is established with the deposition influence as the horizontal coordinate and the corrosion thickness as the vertical coordinate, and the data of all bottom samples at each thickness sampling moment are mapped to the two-dimensional rectangular coordinate system to obtain a number of data points in the two-dimensional rectangular coordinate system. The least squares method is used to perform curve fitting on all data points to obtain a deposition-corrosion correlation function; wherein the least squares method is a well-known technology.

[0099] It should be noted that the velocity-sediment correlation function is expressed as the corresponding functional relationship of the deposition influence on the velocity, and the deposition-corrosion correlation function is the corresponding functional relationship of the corrosion thickness on the deposition influence.

[0100] Specifically, the function value of the flow velocity-sediment correlation function is substituted into the independent variable of the deposition-corrosion correlation function to obtain the flow velocity-sedimentation-corrosion correlation function.

[0101] It should be noted that the flow rate-sedimentation corrosion correlation function represents the corresponding functional relationship between the corrosion thickness caused by deposition and the flow rate. Since the corrosion thickness is mainly affected by sediments at low flow rates and mainly affected by flow velocity at high flow rates, the proportional relationship between the influence of sediments and flow velocity on the corrosion thickness at different flow rates is determined.

[0102] Specifically, for any flow rate, the ratio of the corresponding corrosion thickness of the flow rate in the flow rate-deposition-corrosion correlation function to the corresponding corrosion thickness of the flow rate in the deposition-corrosion correlation function is recorded as the deposition-flow rate-corrosion ratio of the flow rate.

[0103] Step S005: Obtain the anti-corrosion effectiveness test result of the corrosion inhibitor according to the deposition flow rate corrosion ratio of each flow rate.

[0104] It should be noted that in laboratory scenarios, a high-temperature, high-pressure dynamic method is generally used to obtain blank corrosion rates at different flow rates. After adding submarine pipeline corrosion inhibitors, the added corrosion rate is obtained. The effectiveness of the corrosion inhibitor is determined by comparing the blank corrosion rate with the added corrosion rate. However, since pipeline locations covered with sediment will show faster corrosion rates, the influence of sediment needs to be considered when obtaining the blank corrosion rate. Since anti-corrosion agents include corrosion inhibitors, scale inhibitors, and biocides, the effectiveness of these three agents is evaluated.

[0105] Specifically, in the test scenario, the high-temperature and high-pressure dynamic method was used to obtain blank corrosion rates at several flow rates based on formula A.8, A.2 in Appendix A of the standard "GB T 35509-2017 Application and Evaluation of Corrosion Inhibitors in Oil and Gas Fields." The high-temperature and high-pressure dynamic method is a well-known technology, and the specific method is not introduced here.

[0106] For any flow rate, the product of the blank corrosion rate at that flow rate and the deposition flow rate corrosion ratio at that flow rate is recorded as the blank deposition corrosion rate at that flow rate; the maximum value of the blank corrosion rate at that flow rate and the blank deposition corrosion rate is recorded as the actual blank corrosion rate at that flow rate;

[0107] Add a corrosion inhibitor to the pipeline system, and record the obtained deposition velocity corrosion ratio as the dosing corrosion ratio according to the method of steps S001 to S004;

[0108] In the test scenario, the high-temperature, high-pressure dynamic method was used to obtain the corrosion rate of the oil after adding the corrosion inhibitor at various flow rates based on the formula in Section A.8, A.2 of Appendix A of the standard "GB T35509-2017 Application and Evaluation of Corrosion Inhibitors in Oil and Gas Fields." The high-temperature, high-pressure dynamic method is a well-known technology.

[0109] For any flow rate, the product of the dosing corrosion rate at that flow rate and the dosing corrosion ratio at that flow rate is recorded as the dosing deposition corrosion rate at that flow rate; the maximum value of the dosing corrosion rate at that flow rate and the dosing deposition corrosion rate is recorded as the actual dosing corrosion rate at that flow rate.

[0110] Furthermore, under the test scenario, the pitting corrosion rate, uniform corrosion inhibition rate, and pitting corrosion inhibition rate were obtained using the high-temperature and high-pressure dynamic method based on the formulas A.3, A.4, and A.5 in Section A.8 of Appendix A of the standard "GB T 35509-2017 Application and Evaluation of Corrosion Inhibitors in Oil and Gas Fields";

[0111] The actual blank corrosion rate, actual dosing corrosion rate, pitting rate, uniform corrosion rate, and pitting inhibition rate were evaluated according to 7.1.3.2 and 7.1.3.3 of the enterprise standard "QH / S 2064 Requirements for Corrosion Control and Effect Evaluation in Offshore Oil and Gas Field Production Process Systems." Based on the evaluation results, analysis conclusions and maintenance measures were obtained. The specific analysis conclusions and maintenance measures are as follows:

[0112] The analysis conclusions are divided into two categories: "qualified" and "unqualified". The situations that can be judged as "qualified" are as follows:

[0113] 1. Regardless of the actual blank corrosion rate, if the final actual corrosion rate after adding the corrosion inhibitor is no more than 0.03mm / a, there is no pitting corrosion and the compatibility is good, then the corrosion inhibitor meets the requirements;

[0114] 2. After adding the corrosion inhibitor, the final actual corrosion rate is greater than 0.03mm / a, but the actual blank corrosion rate is 0.25mm / a, the corrosion inhibition rate is ≥70%, and there is no pitting corrosion;

[0115] 3. After adding the corrosion inhibitor, the final actual corrosion rate is greater than 0.03mm / a, 0.25mm / a < actual blank corrosion rate ≤ 0.75mm / a, pitting corrosion rate ≤ 0.13mm / a. Compatibility: 1) Meet the requirements of corrosion inhibition rate and pitting corrosion rate in this table; 2) Anti-scaling agent rate effect ≤ 5%; 3) Does not reduce the performance of other chemicals; 4) The corrosion inhibition effect still meets the requirements after adding other chemicals;

[0116] 4. After adding the corrosion inhibitor, the final actual corrosion rate is greater than 0.03mm / a, the actual blank corrosion rate is greater than 0.75mm / a, the corrosion inhibition rate is ≥90%, and the pitting corrosion rate is ≤ 0.21mm / a;

[0117] When the corrosion inhibitor is judged to be "qualified", the maintenance measures can be maintained as they are;

[0118] The following situations may be considered as “unqualified”:

[0119] 1. The actual blank corrosion rate is less than 0.25mm / a, and pitting occurs after adding the drug. The corresponding maintenance measures for this situation are: if there is pitting in the blank and pitting in the added drug, the compatibility of the drugs needs to be considered and the compatibility of the drugs needs to be evaluated; if there is no pitting in the blank and pitting in the added drug, the drug is unqualified and the drug needs to be replaced.

[0120] 2. The actual blank corrosion rate is less than 0.25mm / a, there is no pitting corrosion, and the corrosion inhibition rate is less than 70%. The corresponding maintenance measures in this case are: optimize the reagent concentration. If the corrosion inhibition rate does not increase significantly after increasing the reagent concentration, it is recommended to change the reagent type.

[0121] 3. 0.25mm / a < actual blank corrosion rate ≤ 0.75mm / a, pitting corrosion rate after adding chemicals > 0.13mm / a; the corresponding maintenance measures in this case are: change the chemical type

[0122] 4. 0.25mm / a < actual blank corrosion rate ≤ 0.75mm / a, no pitting, actual corrosion rate after dosing > 0.076mm / a; the corresponding maintenance measures for this situation need specific analysis: If the actual blank corrosion rate of the on-site water is large, combined with the on-site coupon data, if the on-site coupon data is stable and not high, it is necessary to consider whether there is a problem in the test process and retest is required; if the actual blank corrosion rate of the on-site water is large and the on-site coupon corrosion rate is also high, the reagent concentration needs to be adjusted. If the concentration adjustment still cannot meet the requirements, the reagent needs to be replaced; if the actual blank corrosion rate of the simulated water is large, combined with the on-site coupon data analysis, if the on-site coupon data is stable and both are low corrosion, it is recommended to use the on-site data as the standard; if the actual blank corrosion rate of the simulated water is large and the on-site coupon corrosion rate is also high, the reagent concentration needs to be adjusted. If the concentration adjustment still cannot meet the requirements, the reagent needs to be replaced;

[0123] 5. The actual blank corrosion rate is greater than 0.75mm / a, there is no pitting corrosion, and the corrosion inhibition rate is less than 90%. The corresponding maintenance measures in this case are: changing the reagent type;

[0124] 6. The actual blank corrosion rate is greater than 0.75mm / a, and the pitting corrosion rate after adding the agent is greater than 0.21mm / a. The corresponding maintenance measures in this case are: changing the agent.

[0125] Furthermore, the comprehensive anti-scaling rate and pressure change rate of the anti-scaling agent were obtained using titration according to Appendix B7.1 and B7.2 of the enterprise standard "QHS 2057-2021". The titration method is a well-known technique, and the specific method is not introduced here. The effectiveness of the anti-scaling agent was then evaluated according to 5.3.4 of the enterprise standard "QHS 2057-2021". Based on the evaluation results, analysis conclusions and maintenance measures were obtained. The specific analysis conclusions and maintenance measures are as follows:

[0126] If the anti-scaling rate in the analysis conclusion is greater than 60%, the anti-scaling agent is judged to be "qualified";

[0127] If the anti-scaling rate in the analysis conclusion is less than 60%, the anti-scaling agent is judged to be "unqualified" and the corresponding maintenance measures are: consider the compatibility of the agent. If there is no problem with the compatibility of the agent, the agent needs to be replaced.

[0128] Furthermore, the effectiveness of the fungicide was evaluated using the QPCR method according to the standard "SY T 5329-2012 Water Quality Indicators and Analysis Methods for Water Injection in Clastic Reservoirs." The QPCR method is a well-known technique, and the specific method is not described here. Based on the evaluation results, analytical conclusions and maintenance measures were obtained. The specific analytical conclusions and maintenance measures are as follows:

[0129] If the SRB content in the injection water is less than 25 / ml or the SRB content in the mixed pipeline is less than 110 / ml, the fungicide is judged as "qualified";

[0130] If the analysis conclusion shows that the SRB content in the injected water is ≥25 / ml or the SRB content in the mixed pipeline is ≥110 / ml, the fungicide is judged to be "unqualified" and the maintenance measures require changing the agent and selecting a targeted agent for sterilization.

[0131] At this point, the evaluation and maintenance of the effectiveness of anti-corrosion agents including corrosion inhibitors, scale inhibitors and fungicides have been achieved.

[0132] This embodiment adopts Model to present inverse proportional relationship and normalization processing, As the input of the model, the implementer can set the inverse proportional function and normalization function according to the actual situation.

[0133] Another embodiment of the present invention provides a digital comprehensive evaluation system for the effectiveness of submarine pipeline anticorrosion agents. The system includes a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, steps S001 to S005 of the above method are implemented.

[0134] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A digital and intelligent comprehensive evaluation method for the effectiveness of submarine pipeline anticorrosion agents, characterized by: The method comprises the following steps: Obtain the overall flow velocity level and corrosion thickness of each middle specimen and each bottom specimen at each thickness sampling moment; According to the difference in corrosion thickness between the middle sample and the bottom sample at similar overall flow rate levels, the deposition influence of each bottom sample at each thickness sampling time was obtained; According to the negative correlation between the deposition influence degree and the corrosion thickness of the bottom sample at each thickness sampling moment, the flow velocity deposition reference index of each bottom sample at each thickness sampling moment is obtained; according to the flow velocity deposition reference index of the bottom sample at all thickness sampling moments, the analysis reference degree of each bottom sample is obtained; and the flow velocity correlation degree of each bottom sample at each thickness sampling moment is obtained in combination with the flow velocity deposition reference index; The velocity-sediment correlation function was obtained based on the velocity correlation degree of the bottom sample at the thickness sampling time. The deposition-velocity-corrosion ratio of each flow velocity was obtained by combining the overall velocity level and corrosion thickness of the middle sample at each thickness sampling time, as well as the deposition influence and corrosion thickness of the bottom sample at each thickness sampling time. According to the deposition flow rate corrosion ratio of each flow rate, the anti-corrosion effectiveness test results of the corrosion inhibitor are obtained.

2. A digital and intelligent comprehensive evaluation method for the effectiveness of submarine pipeline anticorrosion agents according to claim 1, characterized in that: The method of obtaining the deposition influence of each bottom sample at each thickness sampling moment based on the difference in corrosion thickness between the middle sample and the bottom sample at similar overall flow rate levels includes: According to the similarity of the overall flow velocity levels of the bottom sample and the middle sample at the thickness sampling time, the closeness of the flow velocity of each bottom sample and each middle sample at each thickness sampling time is obtained; No. The bottom specimen is The calculation method of the deposition influence at each thickness sampling moment is: ； Where, For the The bottom specimen is Deposition influence at each thickness sampling moment; For the The bottom specimen and The middle sample is in the The closeness of the flow velocity at each thickness sampling moment; For the The bottom specimen is The corrosion thickness at each thickness sampling moment; For the The middle sample is in the The corrosion thickness at each thickness sampling moment; is the number of middle specimens; is the absolute value function.

3. A digital and intelligent comprehensive evaluation method for the effectiveness of submarine pipeline anticorrosion agents according to claim 2, characterized in that: The method of obtaining the degree of similarity between the flow velocity levels of each bottom sample and each middle sample at each thickness sampling moment based on the similarity of the overall flow velocity levels of the bottom sample and the middle sample at the thickness sampling moment includes the following specific methods: For any bottom sample and any middle sample, the inverse proportional normalization result of the absolute value of the difference between the overall flow velocity levels of the bottom sample and the middle sample at any thickness sampling moment is recorded as the degree of closeness between the flow velocities of the bottom sample and the middle sample at the thickness sampling moment.

4. The digital and intelligent comprehensive evaluation method for the effectiveness of submarine pipeline anticorrosion agents according to claim 1 is characterized in that: The method of obtaining the flow rate deposition reference index of each bottom sample at each thickness sampling moment based on the negative correlation between the deposition influence degree and the corrosion thickness of the bottom sample at each thickness sampling moment includes the following specific methods: No. The bottom specimen is The thickness sampling time and the The bottom specimen is The calculation method of the sedimentation velocity correlation index at each thickness sampling moment is: ； Where, For the The bottom specimen is The thickness sampling time and the The bottom specimen is Sediment velocity correlation index at each thickness sampling moment; For the The bottom specimen is Deposition influence at each thickness sampling moment; For the The bottom specimen is Deposition influence at each thickness sampling moment; is the maximum value of the sedimentation influence of all bottom samples at all thickness sampling moments; It is the maximum value of the overall flow velocity level of all bottom specimens at all thickness sampling moments; For the The bottom specimen is The overall flow velocity level at each thickness sampling moment; For the The bottom specimen is The overall flow velocity level at each thickness sampling moment; is the rounding symbol; is the absolute value function; For any bottom sample at any thickness sampling time, the sum of the deposition velocity correlation index of the bottom sample at the thickness sampling time and all bottom samples at all thickness sampling times is recorded as the velocity deposition reference index of the bottom sample at the thickness sampling time.

5. The digital and intelligent comprehensive evaluation method for the effectiveness of submarine pipeline anticorrosion agents according to claim 1 is characterized in that: The specific method of obtaining the analytical reference degree of each bottom sample based on the flow rate deposition reference index of the bottom sample at all thickness sampling moments is as follows: For any bottom sample, the linear normalization result of the product of the mean and variance of the flow velocity deposition reference index of the bottom sample at all thickness sampling moments is recorded as the analytical reference degree of the bottom sample.

6. The digital and intelligent comprehensive evaluation method for the effectiveness of submarine pipeline anticorrosion agents according to claim 1 is characterized in that: The specific method for obtaining the flow velocity correlation degree of each bottom sample at each thickness sampling moment includes: The linear normalization result of the product of the velocity deposition reference index of any bottom sample at any thickness sampling moment and the analysis reference degree of the bottom sample is recorded as the velocity correlation degree of the bottom sample at the thickness sampling moment.

7. The digital and intelligent comprehensive evaluation method for the effectiveness of submarine pipeline anticorrosion agents according to claim 1 is characterized in that: The flow velocity-sediment correlation function is obtained according to the flow velocity correlation degree of the bottom sample at the thickness sampling time, including the specific method as follows: A two-dimensional rectangular coordinate system was established with the overall flow velocity level as the horizontal coordinate and the sedimentation influence as the vertical coordinate. The data of all bottom samples at each thickness sampling time were mapped to the two-dimensional rectangular coordinate system to obtain several data points in the two-dimensional rectangular coordinate system. The flow velocity correlation degree of each bottom sample at each thickness sampling time was used as the fitting weight of the corresponding data point. The least squares method was used to perform curve fitting on all data points to obtain the flow velocity-sediment correlation function.

8. The digital and intelligent comprehensive evaluation method for the effectiveness of submarine pipeline anticorrosion agents according to claim 1 is characterized in that: The specific method for obtaining the deposition flow rate corrosion ratio of each flow rate is as follows: The velocity-corrosion correlation function was obtained based on the overall velocity level and corrosion thickness of the middle specimen at each thickness sampling moment. The deposition-corrosion correlation function is obtained based on the deposition influence and corrosion thickness of the bottom sample at each thickness sampling moment. Substituting the function value of the velocity-sediment correlation function into the independent variable of the deposition-corrosion correlation function, the velocity-sedimentation-corrosion correlation function is obtained; For any flow rate, the ratio of the corresponding corrosion thickness of the flow rate in the flow rate-deposition-corrosion correlation function to the corresponding corrosion thickness of the flow rate in the deposition-corrosion correlation function is recorded as the deposition-flow rate-corrosion ratio of the flow rate.

9. The digital and intelligent comprehensive evaluation method for the effectiveness of submarine pipeline anticorrosion agents according to claim 1 is characterized in that: The method of obtaining the anti-corrosion effectiveness test result of the corrosion inhibitor according to the deposition flow rate corrosion ratio of each flow rate includes the following specific methods: Obtain blank corrosion rates at several flow rates; For any flow rate, the product of the blank corrosion rate at that flow rate and the deposition flow rate corrosion ratio at that flow rate is recorded as the blank deposition corrosion rate at that flow rate; the maximum value of the blank corrosion rate at that flow rate and the blank deposition corrosion rate is recorded as the actual blank corrosion rate at that flow rate; Obtain the dosing corrosion ratio at each flow rate; obtain the dosing corrosion rate at several flow rates; For any flow rate, the product of the chemical corrosion rate at that flow rate and the chemical corrosion ratio at that flow rate is recorded as the chemical deposition corrosion rate at that flow rate; the maximum value of the chemical corrosion rate at that flow rate and the chemical deposition corrosion rate is recorded as the actual chemical corrosion rate at that flow rate; An evaluation result of the effectiveness of the submarine pipeline corrosion inhibitor is obtained according to the actual blank corrosion rate and the actual added corrosion rate.

10. A digital and intelligent comprehensive evaluation system for the effectiveness of submarine pipeline anticorrosion agents, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the digital comprehensive evaluation method for the effectiveness of submarine pipeline anticorrosion agents as described in any one of claims 1 to 9 are implemented.

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