Safety risk evaluation method and system for coastal oilfield produced water conveying pipeline

Abstract

The invention provides a coastal oilfield produced water conveying pipeline safety risk evaluation method and system, and the system comprises an online monitoring system which is used for obtaining pipeline parameters, and calculating a pipeline safety risk index R according to the pipeline parameters; d is the pipeline damage probability, and ML is the maximum leakage quality; the larger the pipeline safety risk index R is, the higher the pipeline risk is. The online monitoring system is used for collecting operation data of the pipeline, risk calculation and judgment are carried out in combination with pipeline design and operation parameters, an equipment risk sequence is obtained and used for guiding formulation of an inspection plan, and the method has the advantages of being good in real-time performance, high in efficiency and feasible in field calculation.

Description

TECHNICAL FIELD

[0001] The present application mainly relates to the technical field related to oil exploitation, and particularly relates to a safety risk evaluation method and system for offshore oilfield produced water conveying pipelines. BACKGROUND

[0002] Produced water (hereinafter referred to as produced water) refers to the water that is extracted from the formation together with the crude oil, and has undergone most of the processes of crude oil treatment, so the types and properties of impurities in the sewage are greatly related to the geological conditions of the oil reservoir, the quality of the water injection, and the like. This sewage is a complex multiphase system containing solid impurities, liquid impurities, dissolved gas, and dissolved salts, and the like. Due to the complexity of the composition of the produced water, under the joint action of chlorine ions, oil, bacteria, and the like, the produced water conveying pipeline is prone to internal corrosion, and superimposed with external damage to the pipeline caused by the sea wind under the offshore environment, the produced water conveying pipeline is prone to corrosion perforation, causing leakage, polluting the local environment, and endangering personal and property safety.

[0003] The safety risk evaluation of the produced water pipeline is a process of evaluating and judging various safety risks that the produced water pipeline may face during operation. This process involves comprehensive consideration of multiple aspects such as the design, construction, operation, maintenance, and detection of the pipeline.

[0004] Specifically, the safety risk evaluation of the produced water pipeline mainly includes the following aspects:

[0005] 1. Pipeline design and construction risk: evaluate whether the design and construction process of the pipeline meets the relevant safety standards and specifications, whether there are design defects or construction quality problems that may cause safety problems.

[0006] 2. Pipeline operation risk: evaluate the risks that the pipeline may face during operation, such as pipeline leakage, corrosion, mechanical failure, and the like, and the impact of these risks on personnel, environment, and property.

[0007] 3. Pipeline maintenance and repair risk: evaluate the safety risks in the process of pipeline maintenance and repair, such as improper maintenance that may exacerbate pipeline problems, and repair work that may cause new safety risks, and the like.

[0008] 4. Pipeline monitoring and detection risk: evaluate the effectiveness of the pipeline monitoring and detection system, whether it can timely discover pipeline problems and take corresponding measures to prevent the occurrence of safety risks.

[0009] Through comprehensive evaluation of these aspects, the safety risks of the produced water pipeline can be comprehensively judged, and corresponding measures can be taken to reduce or eliminate these risks, to ensure the safe and stable operation of the pipeline.

[0010] Current pipeline management is mainly based on manual inspection and regular inspection, and the same inspection and maintenance scheme is adopted for all similar equipment, which has the disadvantages of low efficiency and high cost.

[0011] Meanwhile, in the existing RBI evaluation method for pipeline detection, the corresponding standards can only stay in the theoretical calculation stage, and the operation process is too complex to be widely applied in the field.

[0012] A buried pipeline external corrosion risk comprehensive evaluation method is disclosed in Chinese patent No. CN201910062116.0, which comprises the following steps: obtaining external corrosion basic parameters, judging whether there is a leak point in the buried pipeline corrosion layer according to the external corrosion basic parameters, and if there is no leak point, it is concluded that the corrosion risk of the buried pipeline is low, and if there is a leak point, it is judged whether the buried pipeline adopts cathodic protection according to the external corrosion basic parameters, and if it does not adopt cathodic protection, the corrosion risk is evaluated according to the direct current interference, alternating current interference and soil corrosivity, and if it adopts cathodic protection, the corrosion risk is evaluated according to the direct current interference, alternating current interference and soil corrosivity.

[0013] The above patent aims to realize multi-factor comprehensive evaluation of buried pipeline external corrosion risk, mainly evaluates the pipeline corrosion risk through external risk factors, does not consider the internal corrosion factors of the pipeline, and cannot accurately evaluate the safety risk of offshore oilfield produced water pipeline.

[0014] A buried oil and gas pipeline risk assessment method is disclosed in Chinese patent No. CN201510169816.1, which comprises the following steps: A. determining the factor set affecting pipeline risk assessment; B. determining the pipeline risk assessment candidate set according to the evaluation requirements; C. calculating the weight of each factor in the pipeline risk factor set by using the entropy weight method; D. calculating the weight of each factor in the pipeline risk factor set by using the combined analytic hierarchy process, and integrating the weight calculated in step C into the analytic hierarchy process calculation process to obtain the final factor weight value; E. using the weight obtained in step D to perform fuzzy evaluation on the pipeline risk single factor; F. iterating the calculation process of step E to realize multi-level fuzzy comprehensive evaluation of buried oil and gas pipeline risk.

[0015] The above patent is applicable to buried oil and gas pipelines, can avoid the problem that the weight of pipeline risk factors is too subjective or too objective, and obtains more objective and accurate factor weights; at the same time, by establishing a fuzzy comprehensive evaluation model to evaluate the risk of buried oil and gas pipelines, the evaluation results are more accurate, objective and reasonable; but it cannot evaluate the influence of internal corrosion, external damage and the combination of the two on the safety of the pipeline. SUMMARY

[0016] In order to solve the technical problems of the prior art, the present application provides a kind of safety risk evaluation method and system for offshore oilfield produced water pipeline in combination with the prior art from practical application, uses online monitoring system to collect pipeline operation data, combines pipeline design and operation parameters, carries out risk calculation and evaluation, obtains equipment risk ranking, and is used to guide the establishment of inspection plan, which has the advantages of good real-time performance, high efficiency and practicality of on-site calculation.

[0017] The technical solutions of the present application are as follows:

[0018] A kind of safety risk evaluation method for offshore oilfield produced water pipeline, including online monitoring system for obtaining pipeline parameters, calculating pipeline safety risk index R according to the pipeline parameters:

[0019] R=D·M L ;

[0020] In the formula: D is the probability of pipeline damage, M L is the maximum leakage mass;

[0021] The greater the pipeline safety risk index R, the higher the pipeline risk.

[0022] Further, the pipeline parameters further include internal corrosion damage index D ic , external corrosion damage index D oc , stress corrosion cracking damage index D scc and mechanical fatigue damage index D mf ;

[0023] The pipeline damage probability D is calculated as follows:

[0024] D ic =d ic f ip f dl .

[0025] Further, the pipeline parameters further include pipeline flow rate Q (kg / h), patrol interval T (h) and field correction coefficient k;

[0026] The M L is the maximum leakage mass, which is calculated as follows:

[0027] M L =QTk.

[0028] Further, the internal corrosion damage index D ic is calculated as follows:

[0029] D ic =d ic f ip f dl

[0030] Where: d is the benchmark index for internal corrosion damage of the pipeline. ic Injection point influence coefficient f ip Blind pipe influence coefficient f dl .

[0031] Furthermore, the mechanical fatigue damage index D mf The calculation is as follows:

[0032] D mf =d mf f m ;

[0033] Where: mechanical fatigue damage benchmark index d mf Vibration reduction measures correction index f m .

[0034] Furthermore, the mechanical fatigue damage benchmark index d is determined based on vibration data collected by the online monitoring system. mf The value, when the vibration level is judged to be low, is the mechanical fatigue damage benchmark index d. mf =1, when the vibration level is judged to be moderate, d mf =50, when the vibration level is judged to be high, d mf =500;

[0035] Based on the vibration reduction measures taken on-site, the vibration reduction measure correction index f is determined. m The value is adjusted by the exponent f when the cause of the abnormal vibration is found and vibration reduction measures are taken. m =0.002, when vibration reduction measures are taken solely based on experience, the correction exponent f is 0.002. m =0.2, when no vibration measures are taken, the correction exponent f is 0.2. m =2.

[0036] Furthermore, a safety risk assessment system for produced water transportation pipelines in offshore oilfields is characterized by comprising:

[0037] Online monitoring system: includes sensors used to acquire pipeline parameters;

[0038] Input module: Configures the pipe flow rate Q, inspection interval T, field correction factor k, and injection point influence factor f. ip Blind pipe influence coefficient f dl Confidence levels of historical inspections of pipelines with internal corrosion, confidence levels of historical inspections of pipelines with external corrosion, confidence levels of historical inspections of pipelines with stress corrosion, and correction index f for vibration reduction measures. m Input;

[0039] Database: Configured to store the baseline index d for internal corrosion damage in pipelines. icCalculation table, external corrosion damage index D oc Calculation table, stress corrosion cracking damage index D scc Calculation table, pipe severity calculation table, mechanical fatigue damage reference index d mf Calculation table

[0040] Processor: configured to calculate the pipe safety risk index R based on the data monitored by the online monitoring system, the parameters input by the input module and the database.

[0041] Further, the sensors include magnetic vibration sensors, atmospheric corrosion monitors, ultrasonic thickness probes, acoustic emission monitors and pH meters.

[0042] Further, the magnetic vibration sensors are used to monitor the pipe vibration amount, the atmospheric corrosion monitors are used to monitor the pipe external corrosion rate, the ultrasonic thickness probes are used to monitor the pipe thickness and internal corrosion speed, the acoustic emission monitors are used to monitor the active crack stress wave signal, and the pH meters are used to measure the pipe liquid pH value.

[0043] The external corrosion degree parameter is represented as nr 外 / δ, n represents the corrosion years (years), and r 外 represents the external corrosion speed (mm / year) obtained by external corrosion monitoring; and δ represents the pipe thickness (mm).

[0044] Further, the probe of the magnetic vibration sensor is fixed on the pipe, the ultrasonic thickness probe is fixed on the pipe outer wall, the probe of the acoustic emission monitor is fixed near the pipe vulnerable place, and the pH meter is deeply inserted into the pipe interior through the flange.

[0045] The beneficial effects of the present application are as follows:

[0046] Through the online monitoring system, multiple parameters in the pipeline operation can be obtained in real time, so that the key data of the pipeline is monitored in real time. Meanwhile, based on the data obtained by the online monitoring system, the risk calculation can be directly performed by the evaluation method provided by the application in combination with the design of the pipeline and the operation related parameters, so that the equipment risk ranking is obtained, thereby guiding the formulation of the inspection plan. Therefore, compared with the traditional periodic inspection mode, the application has the advantages of high efficiency, high accuracy and industrial application. Through the pipeline risk calculation, the current high-risk pipeline can be determined, the high-risk pipeline can be more comprehensively inspected, and the inspection frequency of the low-risk pipeline is reduced, so that the reliability is improved while the inspection cost is reduced. Most of the data are obtained by the online monitoring mode, which is convenient to operate, 24 hours of uninterrupted monitoring, saving labor cost, and failure analysis can be quickly performed according to the monitoring data after damage. The application focuses on the actual application scene, that is, the crude oil produced water pipeline in the coastal environment, ignores the damage mechanism with little influence in this scene, and the method is matched with the online monitoring equipment, which is convenient to use, reduces the difficulty of pipeline management, has high accuracy, and is suitable for field implementation. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 The flow chart of the evaluation method of the application is shown in the figure;

[0048] Figure 2 The principle diagram of the evaluation method of the application is shown in the figure;

[0049] Figure 3 The principle diagram of the evaluation system of the application is shown in the figure. DETAILED DESCRIPTION

[0050] The application will be further described in combination with the drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the application and are not used to limit the scope of the application. In addition, it should be understood that after reading the content taught by the application, those skilled in the art can make various modifications or modifications to the application, and these equivalent forms also fall within the scope defined by the application.

[0051] Embodiment one:

[0052] The embodiment provides a safety risk evaluation method for a coastal oilfield produced water conveying pipeline, which mainly collects operation data by an online monitoring instrument, combines pipeline design and operation parameters, performs risk calculation, obtains equipment risk ranking, and guides the formulation of an inspection plan. For the pipeline with high risk at present, the high-risk pipeline can be more comprehensively inspected, and the inspection frequency of the low-risk pipeline is reduced, so that the reliability is improved while the inspection cost is reduced. Meanwhile, the evaluation method provided by the embodiment is based on the actual application of the coastal oilfield pipeline, and the required calculation parameters can be easily obtained, so that it can be actually applied to the safety risk monitoring and evaluation of the coastal oilfield produced water pipeline.

[0053] like Figure 1 As shown in the figure, the safety risk assessment method for a produced water transportation pipeline in a coastal oilfield provided in this embodiment mainly includes the following steps.

[0054] First, an online monitoring system was established for the produced water delivery pipelines of the coastal oilfield. This system primarily acquires pipeline vibration parameters, external corrosion parameters, internal corrosion parameters, active crack stress parameters, and the pH value of the medium within the pipeline. Specifically, the system includes a magnetic vibration sensor, an atmospheric corrosion monitor, an acoustic emission monitor, and a pH meter.

[0055] in:

[0056] For pipeline vibration, a magnetic vibration sensor is used. The probe is fixed on the pipeline to collect time-domain signals and continuously monitor the pipeline vibration. When the vibration exceeds the threshold, an alarm is triggered and abnormal data is recorded.

[0057] For external corrosion, an atmospheric corrosion monitor is used to monitor the corrosion rate of specimens made of the same pipeline material in a near-shore environment.

[0058] For active crack stress, an acoustic emission probe is used, fixed near the vulnerable part of the pipeline, to continuously monitor the active crack stress wave signal.

[0059] For internal corrosion, an ultrasonic thickness gauge is used, fixed to the outer wall of the pipe, to record the material thickness and the rate of internal corrosion.

[0060] For pH, a pH meter is used to penetrate deep into the pipe through the flange to record the pH value of the medium.

[0061] The data obtained through the online monitoring system is used for both real-time monitoring of pipeline operation and pipeline risk assessment.

[0062] Example 2:

[0063] A method for assessing the safety risks of produced water transport pipelines in offshore oilfields is presented. In this embodiment, the pipeline safety risk assessment considers two aspects: the probability of pipeline damage and the leakage discharge volume. A pipeline safety risk index R is used as the basis for ranking pipeline risks; the higher the pipeline safety risk index R, the higher the pipeline risk. The pipeline safety risk index R is calculated as the pipeline damage probability D and the maximum leakage mass M. L The product of, i.e.:

[0064] R = D·M L

[0065] The probability of pipeline damage is the internal corrosion damage index D. ic External corrosion damage index D ocStress corrosion cracking damage index D scc Mechanical fatigue damage index D mf The sum, that is:

[0066] D = D ic +D oc +D scc +D mf

[0067] The maximum leakage mass is the maximum mass of medium that may be leaked when a leakage accident occurs in the pipeline. It is calculated based on factors such as the flow rate Q (kg / h), the inspection interval T (h), and the field correction factor k.

[0068] M L =QTk

[0069] For the maximum leakage mass in this embodiment, the required pipe flow rate, inspection interval, and on-site correction coefficient can all be easily confirmed. After assigning values ​​to the above parameters, the maximum leakage mass value can be obtained directly.

[0070] Example 3:

[0071] A method for assessing the safety risks of produced water pipelines in offshore oilfields. In this embodiment, the internal corrosion damage index D is... ic External corrosion damage index D oc Stress corrosion cracking damage index D scc Mechanical fatigue damage index D mf The specific calculation method is as follows.

[0072] (1) Pipeline internal corrosion damage index D ic :

[0073] Internal corrosion damage index D oc The benchmark index for internal corrosion damage of pipelines, d ic Injection point influence coefficient f ip Blind pipe influence coefficient f dl The product of:

[0074] D ic =d ic f ip f dl

[0075] Pipeline internal corrosion damage benchmark index d ic Based on the internal corrosion degree parameter (nr) 内 The baseline index d for internal corrosion damage is determined according to Table 1, based on the confidence level of the pipeline's historical inspection data and the internal corrosion data. ic .

[0076] Table 1. Assignment of Pipeline Corrosion Damage Benchmark Index

[0077]

[0078]

[0079] wherein n represents the corrosion years (years); r 内 represents the internal corrosion rate (mm / year) obtained by internal corrosion monitoring of the on-line monitoring system; δ represents the pipe thickness (mm).

[0080] The confidence level of the historical inspection of the internal corrosion pipeline is determined according to Table 2.

[0081] Table 2 Confidence level table of the historical inspection of the internal corrosion pipeline

[0082]

[0083] The confidence level of the historical inspection of the internal corrosion pipeline can be directly determined by the detection method of the internal corrosion of the pipeline. Referring to Table 2, the level is divided into five levels of A, B, C, D and E. In the case that the inspection scheme is internal 100% area visual inspection and thickness measurement, or external key position 50% or more area ultrasonic scanning, the confidence level of the historical inspection of the internal corrosion pipeline is A level; in the case that the inspection scheme is internal 100% area visual inspection and thickness measurement of the connecting pipe position, or external key position 20% or more area ultrasonic scanning, the confidence level of the historical inspection of the internal corrosion pipeline is B level; in the case that the inspection scheme is internal 20% area visual inspection and thickness measurement of the connecting pipe position, or external key position 20% or more area ultrasonic scanning, the confidence level of the historical inspection of the internal corrosion pipeline is C level; in the case that the inspection scheme is internal no more than 20% area visual inspection, or external local ultrasonic scanning, the confidence level of the historical inspection of the internal corrosion pipeline is D level; in the case that the inspection scheme is no detection, the confidence level of the historical inspection of the internal corrosion pipeline is E level.

[0084] After the corresponding level is determined and the internal corrosion degree parameter is determined, the pipeline internal corrosion damage reference index d ic can be directly obtained by table lookup or interpolation method.

[0085] For the injection point influence coefficient f ip : The injection point refers to the position of adding chemical substances (including water) to the main stream. If the pipeline has an injection point and the position is not effectively inspected, the injection point influence coefficient f ip = 3; the pipeline does not have an injection point, or the injection point is effectively inspected, f ip = 1. This parameter belongs to the pipeline design parameter and can be directly obtained.

[0086] For the blind pipe influence coefficient fdl Blind pipe refers to a pipe section that is intermittently operated. If the pipe has a blind pipe section and the blind pipe is not effectively inspected, the blind pipe influence coefficient f dl = 3; if the pipe does not have a blind pipe section or the blind pipe is effectively inspected, f dl = 1. This parameter is a pipe design parameter and can be directly obtained.

[0087] After the pipe internal corrosion damage reference index d ic , the injection point influence coefficient f ip , and the blind pipe influence coefficient f dl are obtained by the above method, the pipe internal corrosion damage index D ic can be directly calculated.

[0088] (2) External corrosion damage index D oc

[0089] According to the specimen corrosion rate r 外 obtained by external corrosion monitoring, the external corrosion degree parameter (nr 外 / δ) is calculated, and the external corrosion damage index D oc is obtained by substituting the confidence level of the pipe historical inspection of external corrosion into Table 1 (in this embodiment, the pipe internal corrosion damage reference index d ic calculation table and the external corrosion damage index D oc calculation table use the same calculation table) and the same calculation table. oc

[0090] The confidence level of the pipe historical inspection of external corrosion is determined according to Table 3.

[0091] Table 3 Confidence level of pipe historical inspection of external corrosion

[0092] Confidence level Inspection scheme A Visual examination of 90% or more of the external surface B Visual examination of 60% or more of the external surface C Visual examination of 30% or more of the external surface D Visual examination of 5% or more of the external surface E Visual examination of less than 5% of the external surface

[0093] The confidence level of the pipe historical inspection of external corrosion can be directly determined by the detection method of the pipe external corrosion. Referring to Table 3, the level is divided into five levels of A, B, C, D, and E. In the case where the inspection scheme is that more than 90% of the external surface is visually inspected, the confidence level of the pipe historical inspection of external corrosion is A level; in the case where the inspection scheme is that more than 60% of the external surface is visually inspected, the confidence level of the pipe historical inspection of external corrosion is B level; in the case where the inspection scheme is that more than 30% of the external surface is visually inspected, the confidence level of the pipe historical inspection of external corrosion is C level; in the case where the inspection scheme is that more than 5% of the external surface is visually inspected, the confidence level of the pipe historical inspection of external corrosion is D level; and in the case where the inspection scheme is that less than 5% of the external surface is visually inspected, the confidence level of the pipe historical inspection of external corrosion is E level.

[0094] After obtaining the confidence level of the pipeline history inspection of external corrosion and the external corrosion degree parameter (nr 外 The external corrosion damage index D oc can be directly obtained by table lookup or interpolation method.

[0095] (3) Stress corrosion cracking damage index D scc

[0096] For the stress corrosion cracking damage of the pipeline, the severity of the pipeline should be first graded according to the pipeline condition, and then the stress corrosion cracking damage index D scc is obtained by table lookup combined with the severity of the pipeline and the confidence level of the pipeline history inspection of stress corrosion cracking.

[0097] For the grading of the severity of the pipeline, refer to Table 4.

[0098] Table 4 Grading of pipeline severity

[0099]

[0100]

[0101] When the active crack propagation of the pipeline is detected by the acoustic emission sensor of the online monitoring system, the severity of the pipeline is defined as high, when the pH < 5.5 and H2S concentration > 1000 ppm or pH > 9 and H2S concentration > 1000 ppm or pH > 8.4 and H2S concentration > 10000 ppm are measured by the pH meter, the severity of the pipeline is defined as medium, and in other cases, the severity of the pipeline is defined as low.

[0102] According to the severity and the confidence level of the pipeline history inspection, the stress corrosion cracking damage index D scc is determined according to Table 5.

[0103] Table 5 Stress corrosion cracking damage index assignment table

[0104]

[0105] Among them, the confidence level of the pipeline history inspection of stress corrosion cracking is determined by Table 6.

[0106] Table 6 Stress corrosion cracking damage confidence level

[0107] Confidence level Inspection scheme A Ultrasonic examination of 25% or more of the welds B Ultrasonic examination of 10% or more of the welds C Ultrasonic examination of less than 10% of the welds D Visual examination for leaks E No examination

[0108] The confidence level of the stress corrosion cracking damage of the pipeline can be directly determined by the detection method of the pipeline stress corrosion cracking damage. Referring to Table 6, the level is divided into five levels of A, B, C, D and E. In the case that more than 25% of the welds are ultrasonically detected, the confidence level of the stress corrosion cracking damage of the pipeline is A. In the case that more than 10% of the welds are ultrasonically detected, the confidence level of the stress corrosion cracking damage of the pipeline is B. In the case that less than 10% of the welds are ultrasonically detected, the confidence level of the stress corrosion cracking damage of the pipeline is C. In the case that visual inspection is performed on the leakage, the confidence level of the stress corrosion cracking damage of the pipeline is D. In the case that no detection is performed, the confidence level of the stress corrosion cracking damage of the pipeline is E.

[0109] After the confidence level of the stress corrosion cracking damage and the severity of the pipeline are determined, the stress corrosion cracking damage index D can be directly obtained by referring to the table. scc Numerical value.

[0110] (4) Mechanical fatigue damage index D mf

[0111] Mechanical fatigue damage index D mf is the product of the mechanical fatigue damage reference index d mf and the damping measure correction index f m .

[0112] D mf = d mf f m

[0113] According to the data collected by the vibration sensor of the online monitoring system, the mechanical fatigue damage reference index d mf is determined according to Table 7.

[0114] Table 7 Mechanical fatigue damage reference index

[0115]

[0116] According to the damping measures taken on the vibration on site, the damping measure correction index f m is determined according to Table 8.

[0117] Table 8 Damping measure correction index

[0118]

[0119]

[0120] After the damping measure correction index f m and the mechanical fatigue damage reference index d mfand the mechanical fatigue damage index D mf .

[0121] After the internal corrosion damage index D ic , the external corrosion damage index D oc , the stress corrosion cracking damage index D scc , the mechanical fatigue damage index D mf are determined by the above method, the pipeline damage probability D can be obtained, and the product of the maximum leakage mass M L can be obtained to obtain the pipeline safety risk index R. In this way, the safety risk level of the pipeline can be determined, and then the pipeline management system can be formulated according to the corresponding level.

[0122] Example Four:

[0123] The embodiment of the present application also provides a safety risk evaluation system for a coastal oilfield produced water pipeline, which is used to execute the above-mentioned evaluation method. The evaluation system mainly comprises an online monitoring system, an input module, a database and a processor.

[0124] The online monitoring system comprises a magnetic vibration sensor for monitoring the vibration of the pipeline, an atmospheric corrosion monitor for monitoring the external corrosion rate of the pipeline, an ultrasonic thickness probe for monitoring the thickness and internal corrosion rate of the pipeline, an acoustic emission monitor for monitoring the active crack stress wave signal, and a pH meter for measuring the pH value of the liquid in the pipeline. The above sensors are used to measure the running data of the pipeline in real time, and the data is sent to the processor.

[0125] The database provided in the embodiment is used to store the internal corrosion damage reference index d ic calculation table, the external corrosion damage index D oc calculation table, the stress corrosion cracking damage index D scc calculation table, the pipeline severity calculation table, the mechanical fatigue damage reference index d mf calculation table, etc. After the processor obtains the input related parameters and the part of the parameters measured by the online monitoring system, the corresponding parameter data can be obtained by automatically querying the database, and finally the pipeline safety risk index R can be directly obtained by the algorithm of the above embodiment.

[0126] The input module of the embodiment is used for the user to input related parameters, which mainly include the in-pipe flow Q, the inspection interval T, the field correction coefficient k, the injection point influence coefficient f ip , the blind pipe influence coefficient f dl , the confidence level of the historical inspection of the internal corrosion pipeline, the confidence level of the historical inspection of the external corrosion pipeline, the confidence level of the historical inspection of the stress corrosion pipeline, and the damping measure correction index f mAfter the relevant parameters are determined, the user can input them into the system through the input module according to the actual pipeline operation, and the processor in the system outputs the pipeline safety risk index R value through calculation after the corresponding parameters are obtained.

[0127] The above merely describes the preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes to the technical scheme and the inventive concept of the present application within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for evaluating the safety risk of a pipeline for transporting offshore oilfield produced water, comprising an online monitoring system for obtaining pipeline parameters, characterized in that, According to the pipeline parameter, a pipeline safety risk index R is calculated: R = D · M L ; where: D = probability of pipe damage, M L is the maximum leak mass; The greater the pipeline safety risk index R is, the higher the pipeline risk is.

2. The method according to claim 1, wherein, The pipeline parameters further include an internal corrosion damage index D ic , an external corrosion damage index D oc , a stress corrosion cracking damage index D scc , and a mechanical fatigue damage index D mf ; The pipeline damage probability D is calculated as follows: D ic = d ic f ip f dl .

3. The method according to claim 2, wherein, The pipeline parameter further comprises an in-pipeline flow Q (kg / h), a patrol interval T (h) and a field correction coefficient k; The M L The maximum leakage mass is calculated as follows: M L = QTk.

4. The method according to claim 3, wherein, The internal corrosion damage index D ic The calculation method is as follows: D ic = d ic f ip f dl In the formula: pipeline internal corrosion damage reference index d ic , injection point influence coefficient f ip , blind pipe influence coefficient f dl .

5. The safety risk evaluation method for the offshore oilfield produced water pipeline according to claim 4, characterized in that, The mechanical fatigue damage index D mf is calculated as follows: D mf = d mf f m ; In the formula: mechanical fatigue damage reference index d mf , damping measure correction index f m .

6. The method according to claim 5, wherein, The mechanical fatigue damage benchmark index d is determined based on vibration data collected by an online monitoring system. mf The value, when the vibration level is judged to be low, is the mechanical fatigue damage benchmark index d. mf =1, when the vibration level is judged to be moderate, d mf =50, when the vibration level is judged to be high, d mf =500; Based on the damping measures taken on site for the vibration, the damping measure correction index f is determined m = 0.002 when the cause of abnormal vibration is found and damping measures are taken m = 0.2 when damping measures are taken only based on experience m = 2 when no vibration measures are taken m = 2.

7. A safety risk assessment system for produced water transportation pipelines in coastal oilfields, characterized in that, It comprises: an online monitoring system comprising sensors for acquiring pipeline parameters; Input module: configured for input of in-line flow rate Q, inspection interval T, field correction factor k, injection point influence factor f ip , blind pipe influence factor f dl , confidence level of historical inspection of internal corrosion, confidence level of historical inspection of external corrosion, confidence level of historical inspection of stress corrosion, damping measure correction index f m . Database: configured to store a pipeline internal corrosion damage benchmark index d ic Calculation table, external corrosion damage index D oc Calculation table, stress corrosion cracking damage index D scc Calculation table, pipeline severity calculation table, mechanical fatigue damage benchmark index d mf Calculation table; a processor configured to calculate a pipeline safety risk index R based on data monitored by the online monitoring system, parameters input by the input module and the database.

8. The offshore oilfield produced water pipeline safety risk assessment system according to claim 7, wherein, The sensors comprise a magnetic vibration sensor, an atmospheric corrosion monitor, an ultrasonic thickness measuring probe, an acoustic emission monitor and a pH meter.

9. The offshore oilfield produced water pipeline safety risk assessment system according to claim 8, wherein, The magnetic vibration sensor is used to monitor the pipeline vibration, the atmospheric corrosion monitor is used to monitor the external corrosion rate of the pipeline, the ultrasonic thickness measuring probe is used to monitor the pipeline thickness and internal corrosion speed, the acoustic emission monitor is used to monitor the active crack stress wave signal, and the pH meter is used to measure the pH value of the liquid in the pipeline. The external corrosion degree parameter is expressed as nr 外 / δ, n represents the number of years (years), r 外 represents the external corrosion rate (mm / year) obtained by external corrosion monitoring; δ represents the pipe thickness (mm).

10. The offshore oilfield produced water pipeline safety risk assessment system according to claim 8 or 9, characterized in that, The probe of the magnetic vibration sensor is fixed on the pipeline, the ultrasonic thickness measuring probe is fixed on the outer wall of the pipeline, the probe of the acoustic emission monitor is fixed near the vulnerable part of the pipeline, and the pH meter is deeply inserted into the inside of the pipeline through the flange.

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