Сравнение и интерпретация результатов обработки данных внутритрубной диагностики для условий транспортировки коррозионно-агрессивного газа

2021 ◽  
pp. 62-71
Author(s):  
Р.К. Вагапов

Many gas and gas condensate fields (Bovanenkovskoye, Urengoyskoye, Kirinskoye, etc.) are distinguished by the presence of corrosive carbon dioxide in the extracted products, which, in the presence of moisture, leads to the formation of local corrosion damage (pits, ulcers and their accumulations). One of the methods for monitoring the corrosion state of pipelines is in-line inspection (ILI), carried out by the magnetic flux leakage method. ILI is especially relevant for underground and subsea pipelines when the use of other methods of corrosion monitoring is limited or costly. Under conditions of gas production, in contrast to oil, corrosion can occur both along the lower generatrix of the pipe (bottom-of-line corrosion) and during condensation of moisture on the upper generatrix of the pipe (top-of-line corrosion). An important process is the correct planning of the ILI, the subsequent processing and interpretation of the obtained data set, which should be carried out taking into account the peculiarities of the development of carbon dioxide corrosion in the gas pipeline and in a comparative analysis with other data of corrosion control. When interpreting ILI data, one should take into account the mechanisms of corrosion development, operating conditions (route relief, etc.) and corrosion monitoring data obtained by other research methods (simulation tests, results obtained at other adjacent sections of pipelines, etc.). Correct and useful information according to ILI data will ensure reliable protection of gas pipelines and planning of measures to protect against internal corrosion.

2020 ◽  
pp. 30-35
Author(s):  
D. N. Zapevalov ◽  
R. K. Vagapov

The use of various intrusive and non-intrusive methods of corrosion monitoring makes it possible to assess the corrosion situation and the effectiveness of the applied corrosion protection agents in conditions of internal corrosion at gas production facilities due to the presence of aggressive gases. The analysis of the application of ultrasonic testing methods as part of corrosion monitoring of internal corrosion at gas production facilities in the presence of corrosive components is carried out. Ultrasonic thickness measurement is widely used as a non-intrusive method for monitoring internal corrosion and detecting corrosion defects in promising gas fields. Many gas fields (Bovanenkovskoye oil and gas condensate field, Urengoy oil and gas field and others) revealed corrosion defects due to cases of internal corrosion due to the presence of increased amounts of carbon dioxide in the produced hydrocarbons. Under conditions of corrosion in the presence of carbon dioxide, ultrasonic methods for measuring the thickness of a metal have certain limitations associated with the unpredictable local nature of carbon dioxide corrosion, which should be considered when used in gas facilities. The main method for measuring thickness under operational conditions is ultrasonic thickness measurement, which is used in conjunction with radiographic monitoring. Using these two main non-intrusive methods, corrosion monitoring monitors the thinning of the metal, the size and depth of local defects and the dynamics of their change over time. Based on the results of measuring the residual wall thickness of the pipe and equipment, the possibility of their further work is determined, and recommendations are made on extending the safe life of gas facilities. The authors analyzed the literature data on new options and technical solutions for the use of ultrasonic methods in the measurement of the thickness of a metal surface.


2021 ◽  
Vol 18 (2) ◽  
pp. 60-71 ◽  
Author(s):  
D. N. Zapevalov ◽  
R. K. Vagapov

Aim.In many fields, the produced gas contains corrosive CO2, which, in combination with moisture and other factors, stimulates the intensive development of corrosion processes, including local ones, which requires careful attention to the assessment of the corrosiveness of operating fluids in order to select effective anti-corrosion protection. Ensuring reliable and safe operation of equipment and pipelines prevents not only man-made risks, but also no less important environmental risks, which are especially dangerous for marine underwater facilities for Arctic coastal facilities.Methods.The analysis of normative and technical documentation in the field of assessment of corrosion risks, aggressive factors of internal corrosion and operating conditions of gas and gas condensate fields has been carried out.Results.One of the criteria for assessing the corrosion hazard is the corrosion rate of steel under operating conditions. However, the normative documents predominantly regulate the general corrosion rate, which evaluates the uniform thinning of the metal. But the rate of local corrosion is in no way taken into account, which is most relevant precisely for the conditions of carbon dioxide corrosion of steel. Another tool for identifying risks can be a corrosion allowance to the pipe wall thickness, which should be selected at the design stage and which is provided to compensate for corrosion losses during the operation of gas pipelines. It is shown that the minimum corrosion allowance (3 mm) specified in the main regulatory documents is insufficient, especially for offshore facilities.Conclusion.The experience of operating gas production facilities confirms that the rate of local corrosion can reach several mm/year. To limit this, effective anti-corrosion measures should be chosen, for example, the use of corrosion inhibitors, and a reasonable level of corrosion allowance should be provided that would take into account the corresponding level of corrosion risks at the gas production facility.


Author(s):  
Per Egil Kvaale ◽  
Tore Ha˚brekke ◽  
Gisle Ro̸rvik

Use of stainless steels in subsea oil and gas production systems have been common through the development of remote controlled subsea oil and gas production systems. Stainless steels are mainly selected to minimize the corrosion due to unprocessed oil and gas and thereby simplifying the internal corrosion protection challenges. Different materials and principles have been implemented from cladding of Carbon Manganese steels to the use of solid stainless steels. For cladding Incoloy 825 or Inconel 625 is common, while the solid stainless steels have been duplex, superduplex or 13%Cr steels in pipes and pipe fittings. Experience from service has shown that these materials have limits in their use, and it is reported various cases where the stainless steels have failed. The present paper will deal with a few examples of failures and possible reasons for these failures.


Author(s):  
Sandeep Vyas

Reliance Gas Pipelines Limited (RGPL) is currently implementing a gas pipeline project from Shahdol, Madhya Pradesh to Phulpur, Uttar Pradesh for evacuation of gas produced from Coal Bed Methane (CBM) blocks owned by Reliance Industries Ltd. This pipeline will be hooked up with GAIL’s HVJ Pipeline at Phulpur. Over all Pipeline system includes 312 km (approx.) long trunk line, and associated facilities such as Compressor Station at Shahdol, Intermediate Pigging facilities, Metering & Regulating facilities at Phulpur and 12 No. Mainline valve stations. Gas produced from CBM blocks will be dehydrated within Gas Gathering Station facilities of CBM Project located upstream of pipeline Compressor station at Shahdol. Gas received at pipeline battery limit is dry and non-corrosive gas in nature, Internal corrosion is not expected in normal course of operation, however internal corrosion of the natural gas pipeline can occur when the pipe wall is exposed to moisture and other contaminants either under process upset conditions or under particular operating conditions. Even though internal corrosion is not expected during normal course of operations, to take care of any eventuality, it is proposed to implement Internal Corrosion Monitoring (ICMS) system in this project. ICMS will provide an efficient and reliable means of continuous monitoring internal corrosion. Internal Corrosion Monitoring (ICMS) system is used as a part of overall integrity management framework; to achieve two objectives viz., verify the corrosive behaviour of gas and to verify the efficacy of applied preventive actions. Philosophy involved in evaluating a suitable CM technique would include : • Applicable corrosion damage mechanisms, anticipated corrosion rates and probable locations. • Suitable CM technique and location based on process condition, system corrosivity, water content, pigging facilities, available corrosion allowance, design life, maintenance etc., • Measurement frequency. Some of the Corrosion Monitoring techniques used for pipeline and of relevance are: • Weight-loss Corrosion Coupons (CC), • Electrical Resistance probes (ER), • Linear Polarization Resistance Probe (LPR) • Ultrasonic Thickness Measurement (UT) • Sampling Points (SP) This paper discusses the merits / demerits of these corrosion monitoring techniques, considerations for selecting a specific technique for the Shahdol – Phulpur Gas Pipeline Project and highlights the implementation of the internal corrosion monitoring system.


Author(s):  
Alexandr Vasiliev ◽  
Svetlana Daškevič

Based on the results of many research years on concrete carbonisation: both immediately after manufacture (using heat-moisture treatment) and in reinforced concrete elements operated for the periods of various length (in an open atmosphere); the effect of carbonisation on the change in the protective properties of concrete in relation to steel reinforcement; for determination of the dependence of the corrosion state of steel reinforcement on the degree of concrete carbonisation in the area of steel reinforcement; the obtained regression dependences of the change (by time in the cross section) of the degree of concrete carbonisation of various classes in strength, – the analysis of the time of the onset of the boundary values of the degrees of concrete carbonisation (strength classes C12/15–C30/37) for the operating conditions of the open atmosphere was performed. Based on it, the regression dependences of the time variation of the depth of corrosion damage of steel reinforcement were construed (for fixed thicknesses of the concrete protective layer). The obtained nature of dependences made it possible to offer, in a general form, the regression dependences of the depth of corrosion damage and corrosion rate of steel reinforcement for concretes (strength classes C12/15–C30/37) for operating conditions in open atmosphere.


2021 ◽  
Author(s):  
Valeriya Eduardovna Tkacheva ◽  
Andrey Nicolaevich Markin ◽  
Ignaty Andreevich Markin ◽  
Alexandr Yuryevich Presnyakov

Abstract Complications associated with a corrosive environment, according to Rosneft's data as of 01.01.2020, are among the prevailing at oil and gas production facilities and rank fourth among other factors complicating production - 12% the complicated mechanized wells. Failures due to corrosion are the second largest complicating factors. Based on the results of approbation, the article proposes a method for calculating the maximum rate of local carbon dioxide corrosion, applicable in oilfield conditions, including to complicated stocks of oil wells and pipelines of oil gathering systems. Based on the approbation results, a method for calculating the maximum rate of local carbon dioxide corrosion, applicable in oilfield conditions, including to complicated stocks of oil wells and oil gathering pipelines systems is proposed in the article. The proposed technique is realizable according to the results one of "traditional" methods the corrosion monitoring - weight (or gravimetric). The approbation results and application possibility the technique in the pilot tests process in assessing the protective ability of corrosion inhibitors and the selection the effective dosages in relation to local damages, which are the main cause the oilfield equipment failures according the factor "Corrosive aggressiveness" (one of the complicating factors in terms of gradation, adopted in the Rosneft Company regulations). On practical examples the oilfield equipment operation, the results of corrosion monitoring and the summary statistics the corrosive stock of wells (using the example of an oil Company), the current situation with respect to this type of complication and relevance the issue under consideration is shown.


2016 ◽  
Vol 830 ◽  
pp. 85-92 ◽  
Author(s):  
Jéssica dos Santos Cruz de Almeida ◽  
José Luiz de Medeiros ◽  
Ofélia Queiroz Fernandes de Araújo

The exploration of pre-salt introduces challenges beyond those posed by ultra-deep waters and the thick of carbonaceous reservoirs. Among the main difficulties are the high gas-oil ratio and the high content of carbon dioxide (CO2) present in the gas. This paper proposes an alternative to the technology currently used in the exploration of pre-salt, in which the gas is treated on the platform. The proposed alternative is applicable to reservoirs which CO2 concentration in gas is greater than 50%, like Jupiter that contains 79% of CO2. For this scenario is suggested that exploration occurs in three production areas: subsea, offshore and onshore. The proposed technology includes the construction of three subsea pipelines: one for the transportation of untreated gas (that is treated onshore); a second for the return of the recovered hydrate inhibitor (in order to be re-injected into the gas pipe) and the last for the return of the carbon dioxide stream separated from the gas.


2021 ◽  
Vol 26 (1) ◽  

Complications associated with a corrosive environment, according to Rosneft’s data at 01.01.2020, are among the prevailing at oil and gas production facilities and rank fourth among other factors complicating production – 12% the complicated mechanized wells. Failures due to corrosion are the second largest complicating factors. Based on the results of approbation, the article proposes a method for calculating the maximum rate of local carbon dioxide corrosion, applicable in oilfield conditions, including to complicated stocks of oil wells and pipelines of oil gathering systems. Based on the approbation results, a method for calculating the maximum rate of local carbon dioxide corrosion, applicable in oilfield conditions, including to complicated stocks of oil wells and oil-gathering pipelines systems is proposed in the article. The proposed technique is realizable according to the results one of «traditional» methods the corrosion monitoring - weight (or gravimetric). The approbation results and application possibility of the technique in the pilot tests process in assessing the protective ability of corrosion inhibitors and the selection of the effective dosages in relation to local damages, which are the main cause the oilfield equipment failures according the factor «Corrosive aggressiveness» (one of the complicating factors in terms of gradation, adopted in the Rosneft Company regulations). On practical examples the oilfield equipment operation, the results of corrosion monitoring and the summary statistics the corrosive stock of wells (using the example of an oil Company), the current situation with respect to this type of complication and relevance the issue under consideration is shown.


2019 ◽  
Vol 121 ◽  
pp. 01019
Author(s):  
Aleksandr Yusupov

In Gazprom dobycha Urengoy LLC, as in other oil-and-gas production enterprises, there are problems of increased equipment wear due to corrosion. A special role there plays CO2 corrosion. Despite the homogeneity of the extracted fluid and even chemical composition of the working medium, the nature and intensity of corrosion damage to pipelines and equipment varies over a wide range, due to different thermobaric parameters of well operation. To determine parameters influencing the rate of corrosion most different methods of statistical analysis were used. The paper provides a methodology for compiling a mathematical model and assessing its reliability. As a result, the equation of carbon dioxide corrosion in relation to the conditions of Achimov deposits of Urengoy oil, gas and condensate field was obtained. The type of the obtained equation was chosen according to the model of the classical de Waard-Milliams carbon dioxide corrosion equation. The model proposed by the authors describes the processes of carbon dioxide corrosion more reliably than the de Waard-Milliams equation does. The disadvantage of the developed model is that it does not reliably describe the speed of corrosion in wells with corrosion rates, significantly exceeding the average values for all wells studied.


Author(s):  
R. K. Vagapov ◽  
D. N. Zapevalov ◽  
K. A. Batullin

The paper investigates aspects of the development of corrosion processes under conditions of moisture condensation in the gas phase in the presence of carbon dioxide, which lead to the formation of local damage. The authors developed and tested a methodology for conducting steels corrosion testing The causes of the formation and the corrosive effect of moisture condensation on steel under conditions of carbon dioxide corrosion at gas production facilities are analyzed. It was found that at elevated temperatures, when the temperature difference is higher, more moisture condenses on the surface of the steel, which leads to an increase in the rate of both general and local corrosion by 2–3 times, compared to room temperature. The increased localization of corrosion processes under conditions of moisture condensation and the presence of CO2 makes the depth index of steel corrosion much higher than the general corrosion rate. When assessing the corrosiveness of environments with condensation of the aqueous phase, the rate of corrosion associated with the depth of the observed corrosion damage should be taken into account. According to the test results, it was determined that samples from the weld compared with the sample from the main body of the pipe differ in the degree of localization of corrosion in conditions of moisture condensation.


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