Stress Corrosion Cracking “Like-in-Kind” Reliability Approach for Pipelines Without Crack Tool In-Line Inspection

2020 ◽  
Author(s):  
Amal Elsisi ◽  
Winston Y. W. Lee ◽  
Pushpendra Tomar ◽  
Dan Williams
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Direct Limit ◽  
Limit State ◽  
Corrosion Cracking ◽  
Pipeline System ◽  
Acoustic Transducer ◽  
Threat Level ◽  
Transmission Pipeline ◽  
Electro Magnetic

Abstract Gas transmission pipeline operators increasingly rely on Electro-Magnetic Acoustic Transducer (EMAT) technology to reliably detect, identify and size stress corrosion cracking (SCC) anomalies in their pipeline system. However, scheduling EMAT in-line inspection (ILI) on every pipeline in the system is not always practicable or achievable in an expeditious manner. A means of conducting a preliminary assessment of the SCC threat on pipelines without EMAT ILI data in an objective and quantifiable manner is useful for understanding the threat level and for prioritizing or deciding on outstanding EMAT inspections. A wealth of system-specific SCC field data from historical integrity excavations across the pipeline system typically exists in a pipeline operator’s dataset and can be readily leveraged for quantitatively estimating the SCC threat reliability in other, similar (“like-in-kind”) parts of the pipeline system. This system-specific data, based on actual SCC findings from integrity excavations, is an improved and more granular alternative to applying industry-wide SCC statistics to estimates of SCC reliability levels on pipelines without EMAT ILI data. This paper presents a robust and direct limit state approach for estimating the SCC reliability level in pipelines that have not yet had an EMAT ILI completed by leveraging system-wide SCC field findings from historical integrity excavations.

Validation of EMAT ILI for Management of Stress Corrosion Cracking in Natural Gas Pipelines

2014 ◽  
Author(s):  
Toby Fore ◽  
Stefan Klein ◽  
Chris Yoxall ◽  
Stan Cone
Keyword(s):  
High Resolution ◽  
Natural Gas ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Probability Of Detection ◽  
Gas Pipelines ◽  
Line Pipe ◽  
Natural Gas Pipelines ◽  
Electro Magnetic

Managing the threat of Stress Corrosion Cracking (SCC) in natural gas pipelines continues to be an area of focus for many operating companies with potentially susceptible pipelines. This paper describes the validation process of the high-resolution Electro-Magnetic Acoustical Transducer (EMAT) In-Line Inspection (ILI) technology for detection of SCC prior to scheduled pressure tests of inspected line pipe valve sections. The validation of the EMAT technology covered the application of high-resolution EMAT ILI and determining the Probability Of Detection (POD) and Identification (POI). The ILI verification process is in accordance to a API 1163 Level 3 validation. It is described in detail for 30″ and 36″ pipeline segments. Both segments are known to have an SCC history. Correlation of EMAT ILI calls to manual non-destructive measurements and destructively tested SCC samples lead to a comprehensive understanding of the capabilities of the EMAT technology and the associated process for managing the SCC threat. Based on the data gathered, the dimensional tool tolerances in terms of length and depth are derived.

Development and Experiences of a Circumferential Stress Corrosion Crack Management Program

2018 ◽  
Author(s):  
Neil Bates ◽  
Mark Brimacombe ◽  
Steven Polasik
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Crack Detection ◽  
Circumferential Stress ◽  
Management Program ◽  
Corrosion Cracking ◽  
Pipeline System ◽  
Average Growth ◽  
Proactive Management ◽  
Inspection Data

A pipeline operator set out to assess the risk of circumferential stress corrosion cracking and to develop a proactive management program, which included an in-line inspection and repair program. The first step was to screen the total pipeline inventory based on pipe properties and environmental factors to develop a susceptibility assessment. When a pipeline was found to be susceptible, an inspection plan was developed which often included ultrasonic circumferential crack detection in-line inspection and geotechnical analysis of slopes. Next, a methodology was developed to prioritize the anomalies for investigation based on the likelihood of failure using the provided in-line inspection sizing data, crack severity analysis, and correlation to potential causes of axial or bending stress, combined with a consequence assessment. Excavation programs were then developed to target the anomalies that posed the greatest threat to the pipeline system or environment. This paper summarizes the experiences to date from the operator’s circumferential stress corrosion cracking program and describes how the pipeline properties, geotechnical program, and/or in-line inspection programs were combined to determine the susceptibility of each pipeline and develop excavation programs. In-line inspection reported crack types and sizes compared to field inspection data will be summarized, as well as how the population and severity of circumferential stress corrosion cracking found compares to the susceptible slopes found in the geotechnical program completed. Finally, how the circumferential SCC time-average growth rate distributions were calculated and were used to set future geohazard inspections, in-line inspections, or repair dates will be discussed.

Validation of EMAT In-Line Inspection Technology for SCC Management

2004 ◽  
Author(s):  
Meera Kothari ◽  
Stephan Tappert ◽  
Uwe Strohmeier ◽  
Jose Larios ◽  
N. Daryl Ronsky
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Crack Detection ◽  
Development Project ◽  
Tool Development ◽  
Service Interruption ◽  
Detection Tool ◽  
Acoustic Transducer ◽  
Electro Magnetic ◽  
Field Correlation

TransCanada has a need to manage sections of the pipeline that are susceptible to stress corrosion cracking (SCC) failure by periodically performing hydrostatic testing. Since hydrostatic testing requires a complete service interruption, In Line Inspection technologies (operating in gas pipelines without liquid couplant) are being investigated as an alternate method to managing this hazard. This requirement resulted in a joint technology and tool development project involving GE Energy and TransCanada. The EmatScan® Crack Detection (CD) tool is designed to detect and size longitudinally oriented external SCC features in gas-filled pipelines. During autumn 2002, the EmatScan® CD tool was run in a 64 km section of the TransCanada system. In 2003, field correlation excavations were conducted to assess the accuracy of the tool. This paper describes the results from the correlation program conducted to validate GE Energy’ 36 inch (914 mm) diameter EMAT (Electro Magnetic Acoustic Transducer) crack detection tool.

scholarly journals Detection and Verification of SCC in a Gas Transmission Pipeline

2000 ◽  
Author(s):  
B. Ashworth ◽  
Neb Uzelac ◽  
H. Willems ◽  
O. A. Barbian
Keyword(s):  
Stress Corrosion ◽  
Wall Thickness ◽  
Stress Corrosion Cracking ◽  
Confidence Level ◽  
Crack Detection ◽  
Corrosion Cracking ◽  
Inspection Method ◽  
Transmission Pipeline ◽  
History Of ◽  
Location Type

Two sections of a 914mm OD (36 in.) TransCanada (TCPL) gas transmission pipeline (predominantly with 9.14 mm wall thickness) were inspected using an ultrasonic liquid coupled crack detection In-Line Inspection (ILI) tool. One of the objectives of the inspection was to establish the condition of the pipeline sections with a known history of stress-corrosion cracking (SCC). Under test was the practicability of inspecting a gas line using a liquid coupled ILI tool, specifically its ability to detect and size defects deeper than 1 mm and distinguish cracks and crack-like defects from other types of anomalies, such as inclusions and laminations. In order to assess the confidence level of the tool, both sections were inspected in two independent runs and the repeatability of inspection was assessed. Cracks and crack-like defects with depths greater than 12.5% of the wall thickness from both runs were compared and correlation was established to assess repeatability. The accuracy of tool predictions was verified in excavations in both sections. 40 reported features, varying in depths up to over 40% were examined with respect to location, type, and size. Examples of defect patterns are shown to demonstrate the accuracy of the inspection method.

Complex Circumferential Stress Corrosion Cracking: Identification, Sizing and Consequences for the Integrity Management Program

2018 ◽  
Author(s):  
Brett Johnson ◽  
Bereket Tesfaye ◽  
Cory Wargacki ◽  
Thomas Hennig ◽  
Ernesto Suarez
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Service Providers ◽  
Circumferential Stress ◽  
Management Program ◽  
Corrosion Cracking ◽  
Pipeline System ◽  
Mountain Areas ◽  
Circumferential Welds ◽  
Circumferential Crack

Since the late 1980’s Ultrasonic tools have been used for the detection and sizing of crack like indications. ILI service providers developed inspection technologies for liquid and gas lines that are widely used nowadays. In comparison to axial cracking, circumferential cracking is not a prevalent risk to most pipelines and therefore is not as well understood. Nevertheless, pipeline Operators observe from time to time circumferentially oriented defects, often in combination with circumferential welds or local stress/strain accumulations. These are often caused by pipeline movement, which may especially occur in mountain areas. With the introduction of Ultrasonic circumferential crack inspection tools in the late 2000’s the knowledge has steadily increased over time. Extensive data collected from in-ditch NDE validations has provided NDT Global with an increased knowledge of the morphology of single cracking and stress corrosion cracking defects both in the axial and circumferential orientations. Field verifications have shown that not all features have the same morphology. Some of the challenges with circumferential cracking are for features that fall outside of the industry standard specifications. These types of features can exhibit characteristics such as being sloped, skewed or tilted. In 2016 NDT Global was approached by Plains Midstream Canada to complete inspections utilizing the 10″ Ultrasonic Circumferential crack inspection technology. The pipeline system spans 188km within Canada and consists of 2 segments. The pipeline traverses several elevation changes and crosses several creeks and roads. Circumferential cracking was identified during dig campaigns performed for other threats, therefore the need to inspect each pipeline segment with the Ultrasonic circumferential technology was identified. Plains Midstream Canada and NDT Global formed a close collaboration to assess the severity of circumferential crack features in this line. This paper will discuss integrity aspects from an Operator and Vendor perspective. Challenges identified due to the morphology of the circumferential crack like indications and derived analysis rules and interpretation methodologies to optimize characterization and sizing are presented. Finally, potential opportunities to maintain the integrity of similar assets by applying some of the findings and enhance the management and decision making process are suggested.

Study of the Susceptibility of API 5L X80 Girth Welds to Sulfide Stress Corrosion Cracking and Hydrogen Embrittlement

2010 ◽  
Author(s):  
Adriana Forero Ballesteros ◽  
Jose´ A. da Cunha Ponciano ◽  
Ivani de S. Bott
Keyword(s):  
Hydrogen Embrittlement ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Oil And Gas ◽  
Hydrogen Permeation ◽  
Sodium Thiosulfate ◽  
Corrosion Cracking ◽  
Transmission Pipeline ◽  
Girth Welds ◽  
Almost All

The growing demand for natural gas and oil, as energy sources, has driven industry’s need for ever-increasing strength levels in oil and gas transmission pipeline materials in order to achieve safe and economic transportation. The current world trend points to the use of pipes with larger diameters and thinner wall thicknesses, operating under high pressure. In addition, pipeline steels for sour service must exhibit good Hydrogen Induced Cracking (HIC) and Sulphide Stress Corrosion Cracking (SSCC) resistance. This study evaluates the susceptibility of API 5L-X80 girth welds to SSCC and Hydrogen Embrittlement (HE). Slow strain rate tensile (SSRT) tests and Hydrogen Permeation tests were performed at room temperature, in different acidic environment containing sodium thiosulfate solutions. Most of the SSRT tests undertaken in solution, showed a loss of ductility and a decrease in the reduction of area, as compared with tests conducted in air. The susceptibility to HE and potentially SSCC was evidenced by a reduction in ductility in the SSRT tests and an increase in the hydrogen permeation current values, for almost all welded joints. This was observed with greater intensity for the more acidic test solutions (pH = 3.4), while for the less acidic test solutions (pH = 4.4) little loss of ductility was observed and the hydrogen permeation current remained at values close to zero, indicating little or no permeation of hydrogen through the metal for the testing times applied. The behaviour exhibited by the samples tested in the more acidic solutions was attributed to the dissolution of material from the sample together with hydrogen embrittlement. These results confirmed that the use of sodium thiosulfate solutions to generate H2S, permits the study of phenomena related to SCC in environments containing sulphides.

Using In-Line Inspection to Address Deformations Containing Near-Neutral pH Stress Corrosion Cracking

2002 ◽  
Author(s):  
Dennis C. Johnston ◽  
Thomas G. Hrncir
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Transverse Field ◽  
Corrosion Cracking ◽  
Slope Deformation ◽  
Pipeline System ◽  
Dissolved Carbon ◽  
Neutral Ph ◽  
Ph Stress ◽  
Pipe Line

Marathon Ashland Pipe Line LLC (MAPL) experienced a pipeline release on January 27, 2000 from cracking in a bottom-side shallow deformation. The crack that caused the release was determined to have propagated due to corrosion fatigue that progressed from an area of near-neutral pH stress corrosion cracks. A combination of a transverse field magnetic flux inspection (TFI) tool and a slope-deformation tool were used to inspect the entire pipeline segment for additional injurious deformations that could contain cracks. The TFI tool data were used to differentiate deformations that contained linear indications (typically cracks or corrosion) from deformations that did not. The slope-deformation tool data were used to measure the deformation magnitudes and shapes and to assist with locating the (TFI) deformations that were to be excavated. The pipe conditions necessary for these types of cracking to occur are discussed as well as the findings of the in-line inspection and remediation program. Prior to this release, it was perceived within the industry that constrained shallow deformations were not likely to fail catastrophically. The failure mechanism, particularly from constrained deformations, was normally as a leak. The near-neutral pH stress corrosion cracking phenomenon within deformations was first thought to be a unique event. Based on the investigation program conducted by MAPL, this phenomenon was identified elsewhere within the pipeline system. Based on MAPL’s investigation, pipelines susceptible to or containing slight deformations (typically high D/t ratios) in areas with groundwater containing high levels of dissolved carbon dioxide and coated with materials prone to shielding cathodic protection may be particularly susceptible to the deformation near-neutral pH stress corrosion cracking phenomenon.

Now You SCC Me, Now You Don’t: Using Machine Learning to Find Stress Corrosion Cracking

2020 ◽  
Author(s):  
Michael Smith ◽  
Aidan Blenkinsop ◽  
Matthew Capewell ◽  
Brian Kerrigan
Keyword(s):  
Machine Learning ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Acoustic Waves ◽  
Good Practice ◽  
Metal Structure ◽  
Corrosion Cracking ◽  
Supervised Machine Learning ◽  
Pipeline System ◽  
Electromagnetic Acoustic Transducer

Abstract Electromagnetic Acoustic Transducer (EMAT) is a non-destructive inspection technology that uses guided acoustic waves to detect planar flaws in a metal structure. When deployed via in-line inspection (ILI), it is an effective way to detect cracks in a pipeline. EMAT has thus become a staple of crack management programs throughout the world since its introduction to the market over a decade ago. As with all technologies, challenges remain with the inspection process. One such challenge with EMAT is classification. While it is possible to determine that a defect is “crack-like” (a property determined by its tendency to reflect incident waves), it is difficult to determine the nature of the defect from the EMAT measurement alone. Indeed, similar reflections are obtained for many different types of defects, from relatively benign manufacturing and construction abnormalities, to more concerning anomalies such as stress corrosion cracking (SCC). To compensate for the difficulties in classification, it is good practice to follow up an EMAT inspection with a number of in-field verifications. These investigations allow for a more direct observation of classification and size, and provide valuable information about the nature of cracks. They are, however, expensive — meaning that avoiding unnecessary digs is a top priority. In this paper, we document a developing approach to post-ILI crack management, whereby the results of an EMAT run are combined with those from field verifications to maximize the amount of information gained from costly field work. This approach — which relies on supervised machine learning — leads to a marked improvement in the classification of crack-like indications from EMAT, and allows future investigations to be prioritized according to the likelihood of finding a concerning defect. The method was trialed on a pipeline system with extensive SCC, leading to an improved success rate in finding SCC, and a more cost effective crack management plan.

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