Microbial corrosion failure analysis method for oil and gas transmission pipeline
Through the service history survey and on-site sampling analysis of oil and gas conveying pipelines, combined with DNA sequencing and chemical composition analysis, the microbial community and corrosion products are clarified, and the possibility of microbial corrosion is inferred, which solves the problem of insufficient accuracy of microbial corrosion failure analysis in the existing technology, and achieves higher analysis accuracy and reliability.
Patent Information
- Application Number
- CN202311851133.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-29
- Publication Date
- 2025-07-01
AI Technical Summary
The prior art has problems of insufficient accuracy and reliability in the analysis of microbial corrosion failure in oil and gas conveying pipelines, especially in complex actual working conditions and mechanisms of microbial corrosion.
By investigating the service history of oil and gas conveying pipelines, combining on-site upstream and downstream fluid sampling and analysis, DNA sequencing, chemical composition analysis and physical phase analysis, the microbial community and abundance in solid products, the material composition of solid products, and the possibility of microbial corrosion and its contribution to pipeline failure are inferred through microscopic observation and energy spectrum analysis.
It improves the accuracy and reliability of microbial corrosion failure analysis, can effectively identify microbial corrosion problems, avoid waste of maintenance costs and time losses caused by misjudgment, and improves the operating safety and reliability of pipelines.
Smart Images
Figure BDA0004641041460000071 
Figure BDA0004641041460000081
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of maintenance and fault diagnosis of oil and gas transportation systems, and particularly relates to a method for analyzing the microbial corrosion failure of oil and gas transportation pipelines. Background Art
[0002] With the continuous increase in the production of oil and gas, the safety and reliability of oil and gas transportation pipelines become particularly important. However, due to the complex and variable geological conditions, oil and gas transportation pipelines may face various harsh environments during actual operation, such as high-sulfur oil and gas fields, high-salt formations, etc. In these environments, pipelines are prone to microbial corrosion failure problems. Therefore, it is of great significance to study the causes and influencing factors of microbial corrosion failure of oil and gas transportation pipelines.
[0003] Currently, the research on microbial corrosion of oil and gas transportation pipelines at home and abroad mainly focuses on two aspects: laboratory simulation experiments and field actual working condition investigations. Laboratory simulation experiments mainly study the growth conditions and corrosion mechanisms of microorganisms in different environments by controlling factors such as temperature, pH value, and oxygen concentration. However, it is difficult to fully simulate the complex environment under actual working conditions, so there may be limitations in explaining pipeline corrosion problems in the field. In addition, field actual working condition investigations mainly rely on the understanding of the pipeline service history and sampling and analysis of the failed pipelines. However, this method is often restricted by field conditions, such as the accuracy of sampling locations, difficulties in sample preservation and processing, etc., which may all lead to deviations in the analysis results.
[0004] In view of the above problems, the present invention proposes a process and method for analyzing the microbial corrosion failure of oil and gas transportation pipelines, aiming to improve the accuracy and reliability of microbial corrosion failure analysis. This method investigates the service history of oil and gas transportation pipelines to understand the pipeline operation environment and conditions, providing basic information for subsequent corrosion failure analysis. At the same time, by sampling and analyzing the upstream and downstream fluids of the failed pipelines, information such as the solid products on the inner surface of the pipeline, the perforation sites, and the solid products at the bottom and around the local corrosion pits is obtained. Combining methods such as DNA sequencing, chemical composition analysis, and phase analysis, the microbial community and abundance in the solid products and the material composition of the solid products are determined. In addition, the water samples collected on-site are also analyzed to measure the composition of their main ions and determine the number of bacteria such as SRB, TGB, and FB by the MPN method, so as to more comprehensively understand the environmental conditions of microbial corrosion. Finally, through microscopic observation and energy spectrum analysis of the perforation or corrosion pit sites, combined with information such as the types and quantities of microorganisms, the types and quantities of microorganisms in the transported fluid, and the acidic gas content in the transported fluid, the possibility of microbial corrosion and its contribution to pipeline failure are inferred, thereby determining the cause of pipeline failure. Summary of the Invention
[0005] To address the deficiencies of the prior art, the present invention provides a method for analyzing the microbial corrosion failure of oil and gas transmission pipelines. By investigating the service history of the pipelines, taking on-site samples and analyzing them, and combining means such as DNA sequencing, chemical composition analysis, and phase analysis in the laboratory, the cause of pipeline failure can be accurately determined, avoiding misdiagnosis.
[0006] The technical solution provided by the present invention is as follows:
[0007] A method for analyzing the microbial corrosion failure of oil and gas transmission pipelines, comprising the following steps:
[0008] 1) Obtain the historical service data of the oil and gas transmission pipeline to be analyzed, so as to understand information such as the pipeline's usage environment and operating conditions, providing basic data for subsequent failure analysis. When it is determined based on the data that there is a risk of microbial corrosion failure, proceed to the next step;
[0009] 2) Conduct on-site collection and data detection of the transmission fluid (including water samples and gas samples) in the oil and gas transmission pipeline to be analyzed, and / or conduct on-site collection and analysis of the solid products on the cut section of the oil and gas transmission pipeline segment to be analyzed. These data help analyze the possibility and severity of microbial corrosion. When it is determined based on the data that there is a risk of microbial corrosion failure, proceed to the next step;
[0010] 3) Detect the microorganisms in the cut section of the oil and gas transmission pipeline segment to be analyzed. These data help analyze the possibility and severity of microbial corrosion. When it is determined based on the data that there is a risk of microbial corrosion failure, proceed to the next step;
[0011] 4) Conduct a cross-sectional analysis of the perforated or pitted parts in the cut section of the oil and gas transmission pipeline segment to be analyzed to determine the corrosion products. When it is determined based on the data that there is a risk of microbial corrosion failure, proceed to the next step;
[0012] 5) Based on the results of steps 1) to 4), comprehensively analyze the results of microorganisms in the environment, the composition of products at the failure site, and the results of microbial analysis, effectively evaluate the possibility of microbial corrosion and its contribution to failure, thereby accurately determining the cause of pipeline failure and avoiding waste of maintenance costs and time losses caused by misjudgment.
[0013] Specifically, in step 1), the types of data obtained include: the operating conditions of the pipeline (such as temperature, pressure), the type of transmission fluid, the content of CO2 and H2S, the water sample test report, the pipeline material and specifications, the service time, etc.
[0014] Generally, when the temperature does not exceed 90 °C and there are corrosive bacteria in the water sample (such as more than 25 SRB per mL), it can be determined that there is a risk of microbial corrosion.
[0015] Specifically, in step 2):
[0016] The types of data obtained from the upstream and downstream of the oil and gas pipeline to be analyzed for the transported fluid include: ionic composition; pH value; number of corrosive microorganisms;
[0017] The ionic composition includes but is not limited to: Fe 2+ , Fe 3+ , HCO3 - , CO3 2- , S 2- , SO4 2- , Cl - , Ca 2+ , Mg 2+ , Na + , K + ;
[0018] The number of bacteria includes the number of SRB, TGB, and FB bacteria, which can be determined by the MPN method.
[0019] Generally, when Fe 2+ / Fe 3+ , S 2- , SO4 2- , and a relatively high concentration of Cl - (exceeding 10 g / L) are detected in the water sample, and corrosive bacteria (such as SRB exceeding 25 cells / mL) are detected, it can be judged that there is a risk of microbial corrosion.
[0020] Specifically, in step 2), the types of data obtained from the solid products in the oil and gas pipeline to be analyzed include: microbial community; number of corrosive microorganisms; material composition of the solid products.
[0021] Generally, when a large number of corrosive bacteria (such as SRB exceeding 10 4 copies / mL) and possible reaction products (such as the corrosion product FeS of SRB) are detected in the solid products, it can be judged that there is a risk of microbial corrosion.
[0022] Specifically, in step 3), the types of data obtained from the microorganisms in the oil and gas pipeline to be analyzed include: microbial community; number of corrosive microorganisms.
[0023] Generally, when a large number of corrosive bacteria (such as SRB exceeding 10 4 copies / mL) and possible reaction products (such as the corrosion product FeS of SRB) are detected, it can be judged that there is a risk of microbial corrosion.
[0024] Specifically, in step 4), the types of data obtained from the cross-sectional analysis of the perforated or pitted parts in the oil and gas transmission pipeline include: the morphology of the corrosion products; the phase of the corrosion products; the composition of the corrosion products.
[0025] Generally, when EPS components (such as C, P, N, etc., with a mass percentage exceeding 1%) and possible bacterial corrosion products (such as FeS) are detected in the products, it can be judged that there is a risk of microbial corrosion.
[0026] Specifically, in step 5): Based on information such as the material composition of the products at the perforated or pitted positions, the types and quantities of microorganisms, the types and quantities of microorganisms in the transported fluid, and the content of acidic gases in the transported fluid, infer the possibility of microbial corrosion and its contribution to pipeline failure, so as to determine the cause of pipeline failure.
[0027] Generally, when the pipeline service temperature does not exceed 80 °C, corrosive bacteria (such as SRB exceeding 25 / mL) are detected in the water sample, EPS components (such as C, P, N, etc., with a mass percentage exceeding 1%) are detected in the solid products, a large number of corrosive bacteria (such as SRB exceeding 10 4 copies / mL) and possible bacterial corrosion products (such as FeS) are detected, it can be judged that there is a risk of microbial corrosion.
[0028] Specifically, after cutting the failed pipe section, collect the solid products on the inner surface of the pipeline, the products at the perforated part, and the solid products at the bottom and around the local pits on-site, and seal them with a special sterilized bag to prevent the samples from being contaminated during transportation and ensure the accuracy of the analysis results.
[0029] Specifically, when collecting the solid products, it is necessary to purge the inner surface of the failed pipe section with nitrogen to keep it in a dry state to prevent the occurrence of secondary oxidation reactions.
[0030] Specifically, after cutting the perforated part and the local pitted part, perform epoxy resin embedding and treatment on them, and finally use the method of metallographic sample preparation to gradually grind until polishing;
[0031] Furthermore, observe the microscopic morphology of the products at the perforated or pitted parts under the backscattered electron signal of the scanning electron microscope, and analyze the chemical composition in the product layer by using the line scan or area scan function of the energy spectrometer;
[0032] Furthermore, combine the micro-area X-ray diffraction technology to analyze the phase structure of the products in different parts, so as to judge the material composition of the products.
[0033] Specifically, through DNA sequencing, chemical composition analysis and phase analysis, clarify the microbial community and abundance in the solid products and the material composition of the solid products.
[0034] Compared with the prior art, the present invention has at least the following beneficial effects:
[0035] 1. By deeply analyzing the service history of the oil and gas transportation pipeline, the environmental conditions and operating status of the pipeline can be better understood, providing comprehensive information support for the analysis of microbial corrosion failure.
[0036] 2. By collecting the transported fluid at the upstream and downstream in the field and conducting relevant detections, the environmental changes inside the pipeline can be grasped in real time, which helps to judge the occurrence and development process of microbial corrosion.
[0037] 3. Timely treatment of the inner surface of the failed pipe section can avoid the occurrence of secondary oxidation reaction, ensure the authenticity of the sample, and is conducive to subsequent analysis of microbial corrosion failure.
[0038] 4. Through multiple analyses of the solid products, the microbial community and its abundance, as well as the material composition of the solid products, can be comprehensively understood, which helps to reveal the process and mechanism of microbial corrosion.
[0039] 5. Laboratory analysis of the on-site water samples can obtain their main ion composition, as well as the quantities of bacteria such as SRB, TGB, and FB, which helps to evaluate the risk and impact of microbial corrosion.
[0040] 6. Combining the analysis of the microscopic morphology and chemical composition of the products at the perforated or pitted parts can accurately judge the possibility of microbial corrosion and its contribution to pipeline failure, thereby determining the cause of pipeline failure.
[0041] 7. Through the analysis of microorganisms in the environment and the comprehensive analysis of the product composition at the failure site, the possibility of microbial corrosion and its contribution to failure can be effectively evaluated, avoiding unnecessary losses caused by misjudgment.
[0042] In summary, the present invention provides a comprehensive method for analyzing microbial corrosion failure of oil and gas transportation pipelines, which can effectively identify microbial corrosion problems, provide strong support for pipeline maintenance and repair, and improve the operation safety and reliability of pipelines. Specific Embodiments
[0043] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention.
[0044] Example 1
[0045] In a specific implementation of the analysis of microbial corrosion failure of an oil and gas transportation pipeline, the analysis process specifically includes the following steps:
[0046] 1. Investigate and study the service history of the oil and gas transmission pipeline to understand information such as the pipeline's usage environment and operating conditions. The specific data is shown in Table 1;
[0047] Table 1 Survey data of the service history of the oil and gas transmission pipeline
[0048] Investigation content Investigation results Temperature The inlet temperature is 87°C and the outlet temperature is 74°C Pressure The maximum is 4.5 MPa Pipeline material and specifications X65, outer diameter 323.9 mm, wall thickness 12.7 mm Fluid transported Crude oil (oil, gas, water) <![CDATA[CO2 content]]> Average 6% <![CDATA[H2S content]]> Maximum 50 ppm Water sample test report Yes Service time 13 months
[0049] 2. When the oil and gas transmission pipeline fails, collect the transported fluids (including water samples and gas samples) at the upstream and downstream of the pipeline respectively, and measure the pH value of the water sample on-site. At the same time, detect the number of common corrosive bacteria. The specific data is: pH is 6.76, the number of SRB is 11,000 cells / mL, the number of TGB is 7,000 cells / mL, and the number of FB is 110 cells / mL;
[0050] 3. After cutting the failed pipe section, quickly collect the solid products on the inner surface of the pipeline, the perforated part, and the solid products at the bottom and around the local corrosion pits on-site, and seal and store them in a special sterilized bag;
[0051] 4. When collecting the solid products, it is necessary to purge the inner surface of the failed pipe section with nitrogen to keep it in a dry state to prevent the occurrence of secondary oxidation reactions;
[0052] 5. The failed pipe section should be packaged as soon as possible and sent back to the laboratory for analysis;
[0053] 6. In the laboratory, conduct DNA sequencing, chemical composition analysis, and phase analysis on the solid products collected on-site to clarify the microbial community and abundance in the solid products and the specific composition of the solid products. The specific data is: the main species in the solid products include Proteobacteria, Desulfobacterota, and Firmicutes. Quantitative PCR analysis found that the number of SRB is 7.41×10 9 copies / mL, and the solid products are composed of FeCO3, FeS, SiO2, and FeO(OH);
[0054] 7. Analyze the main ion composition of the water samples collected on-site in the laboratory, including but not limited to: Fe 2+ 、Fe 3 + 、HCO3 - 、CO3 2- 、S 2- 、SO4 2- 、Cl - 、Ca 2+ 、Mg 2+ 、Na + 、K + etc. The specific data is shown in Table 2;
[0055] Table 2 Test results of water samples
[0056]
[0057]
[0058] 8. Based on information such as the material composition of the products at the perforation or pitting positions, the types and quantities of microorganisms, the types and quantities of microorganisms in the transported fluid, and the content of acidic gases in the transported fluid, infer the possibility of microbial corrosion and its contribution to pipeline failure, so as to determine the cause of pipeline failure. Specifically, from the above, the operating temperature of the pipeline is lower than 90°C, the transported fluid is crude oil (containing water and associated gas), the gas contains 6% CO2 and 50 ppm H2S, corrosive microorganisms are detected in the water sample (11,000 / mL of SRB, exceeding 25 / mL), and high-concentration chloride ions (16,953 mg / L, exceeding 10,000 mg / L), and various microbial communities (mainly Proteobacteria, Desulfobacterota, and Firmicutes) and a large number of SRB (7.41×10 9 copies / mL, exceeding 10 4 copies / mL) are detected in the solid sample, and FeCO3 (CO2 corrosion product), FeS (SRB corrosion product), SiO2 (deposit layer), FeO(OH), and EPS component (P content is 4.65 wt%, exceeding 1%) are detected in the corrosion product. It can be determined that the cause of pipeline failure is the combined corrosion of sulfate-reducing bacteria and CO2;
[0059] 9. Finally, by comprehensively analyzing the results of microbial analysis in the environment, the product composition at the failure site, and the results of microbial analysis, effectively evaluate the possibility of microbial corrosion and its contribution to failure, so as to accurately judge the cause of pipeline failure and avoid waste of maintenance costs and time loss caused by misjudgment. Specifically, due to the comprehensive consideration of operating conditions (temperature lower than 90°C, transported fluid is water-containing crude oil), the number of corrosive bacteria in the water sample (11,000 / mL of SRB, exceeding 25 / mL), the number of corrosive bacteria in the solid sample and the products near the pitting (7.41×10 9 copies / mL, exceeding 10 4 copies / mL), and the corrosion product (FeS) and EPS component (P content is 4.65 wt%, exceeding 1%), it can be accurately judged that SRB is the main inducement for pipeline failure.
[0060] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.
Claims
1. A method for analyzing the microbial corrosion failure of oil and gas transmission pipelines, characterized in that, It includes the following steps: 1) Obtain the historical service data of the oil and gas transmission pipeline to be analyzed. When it is judged that there is a risk of microbial corrosion failure based on the data, proceed to the next step; 2) Conduct on-site collection and data detection of the transmission fluid in the oil and gas transmission pipeline to be analyzed, and / or conduct on-site collection and analysis of the solid products on the cut section of the oil and gas transmission pipeline to be analyzed. When it is judged that there is a risk of microbial corrosion failure based on the data, proceed to the next step; 3) Detect the microorganisms in the cut section of the oil and gas transmission pipeline to be analyzed. When it is judged that there is a risk of microbial corrosion failure based on the data, proceed to the next step; 4) Conduct a cross-sectional analysis of the perforated or pitted parts in the cut section of the oil and gas transmission pipeline to be analyzed to determine the corrosion products. When it is judged that there is a risk of microbial corrosion failure based on the data, proceed to the next step; 5) Judge whether microbial corrosion failure has occurred in the oil and gas transmission pipeline according to the results of steps 1) to 4).
2. The method for analyzing the microbial corrosion failure of an oil and gas transmission pipeline according to claim 1, wherein In step 1), the types of data obtained include: operating temperature of the pipeline, operating pressure, types of transmission fluid, CO2 and H2S content, water sample test report, pipeline material and specifications, commissioning time, etc.
3. The method for analyzing the microbial corrosion failure of an oil and gas transmission pipeline according to claim 1, wherein In step 2): The types of data obtained from the transmission fluid at the upstream and downstream of the oil and gas transmission pipeline to be analyzed include: ionic composition; pH value; corrosive microorganisms and quantity; The ionic composition includes but is not limited to: Fe 2+ 、Fe 3+ 、HCO3 - 、CO3 2- 、S 2- 、SO4 2- 、Cl - 、Ca 2+ 、Mg 2+ 、Na + and K + ; The quantity of bacteria includes the quantity of SRB, TGB and FB bacteria.
4. The method for analyzing the microbial corrosion failure of an oil and gas transmission pipeline according to claim 1, wherein In step 2), the types of data obtained from the solid products in the oil and gas transmission pipeline to be analyzed include: microbial community; quantity of corrosive microorganisms; material composition of the solid products.
5. The method for analyzing the microbial corrosion failure of an oil and gas transportation pipeline according to claim 1, characterized in that, In step 3), the types of data of microorganisms obtained from the oil and gas transmission pipeline to be analyzed include: microbial community; quantity of corrosive microorganisms.
6. The method for analyzing the microbial corrosion failure of an oil and gas transportation pipeline according to claim 1, wherein In step 4), the types of data obtained from the cross-sectional analysis of the perforated or pitted parts in the oil and gas transmission pipeline include: morphology of the corrosion products; phase of the corrosion products; composition of the corrosion products.
7. The method for analyzing the microbial corrosion failure of oil and gas transmission pipelines according to claim 1, characterized in that In step 5): Judge whether microbial corrosion failure has occurred in the oil and gas transmission pipeline according to the material composition of the products at the perforated or pitted positions, the types and quantities of microorganisms, the types and quantities of microorganisms in the transmission fluid, and the content of acidic gases in the transmission fluid.
8. The method for analyzing microbial corrosion failure of an oil and gas transmission pipeline according to claim 1, characterized in that: After cutting the failed pipe section, collect the solid products on the inner surface of the pipeline, the solid products at the perforated part, the bottom and around the local pitting at the site, and seal and store them with a special sterilized bag; When collecting the solid products, it is necessary to conduct nitrogen purging on the inner surface of the failed pipe section to keep it in a dry state to prevent the occurrence of secondary oxidation reaction.
9. The method for analyzing the microbial corrosion failure of an oil and gas transmission pipeline according to claim 1, characterized in that: After cutting the perforated part and the local pitting part, conduct epoxy resin embedding and treatment on them, and finally polish them step by step by means of metallographic sample preparation until they are polished; Observe the microscopic morphology of the products at the perforated or pitted parts under the backscattered electron signal of a scanning electron microscope, and analyze the chemical composition in the product layer by using the line scanning or area scanning function of an energy spectrometer; Combined with micro-area X-ray diffraction technology, analyze the phase structure of the products at different parts to judge the material composition of the products.
10. The method for analyzing the microbial corrosion failure of an oil and gas transportation pipeline according to claim 1, characterized in that: Through DNA sequencing, chemical composition analysis, and phase analysis, clarify the microbial community and abundance in the solid product, as well as the material composition of the solid product.