Inspection Considerations for Deepwater Thick-Walled Riser Systems

2008 ◽  
Author(s):  
Jonathan Bowman ◽  
Hugh Thompson ◽  
Donald Stevens ◽  
James Crane
Keyword(s):  
Fatigue Loading ◽  
Thick Wall ◽  
Inspection System ◽  
Acceptance Criteria ◽  
Adequate Knowledge ◽  
Inspection Process ◽  
Engineering Requirement ◽  
Weld Inspection ◽  
Girth Welds ◽  
The Impact

The fatigue loading on deepwater risers results in the need to impose very tight weld acceptance criteria for pipe alignment and flaw sizes. The production of high-pressure, high-temperature reservoirs calls for increasingly thick-walled riser systems. The combination of thicker wall pipe and the maintenance of tight flaw acceptance criteria challenges automated ultrasonic testing (AUT) which is the primary method of riser weld inspection. An understanding of the limitations of the weld inspection system must be determined and accommodated as part of the engineering process and in conjunction with adequate knowledge of the pipe end dimensions can help optimize the inspection process. This paper discusses the challenges associated with the preparation for and inspection of thick-walled riser system welds and the impact this can have on the system design and engineering requirement. In support of the discussion an overview of a recent study to determine the detect-ability and sizing accuracy of an AUT system with thick-wall pipe girth welds is presented. The qualification program is based upon the AUT inspection of seeded defect welds which are subsequently cut into weld rings, re-inspected with an immersion scan and sectioned to determine the size of the flaws present. All AUT inspections are performed under similar conditions to the inspection of the production welds (i.e., no prior knowledge of the nature of the seeded welds).

An Integrated Approach to Welding, AUT and ECA for Pipeline Construction

2014 ◽  
Author(s):  
David Horsley ◽  
Jing Ma ◽  
Jan van der Ent ◽  
Casper Wassink ◽  
Martin Fingerhut
Keyword(s):  
Integrated Approach ◽  
Final Outcome ◽  
Critical Element ◽  
Unified Approach ◽  
Acceptance Criteria ◽  
Pipeline Construction ◽  
Girth Welds ◽  
Design Options ◽  
The Impact ◽  
Welding Productivity

An integrated approach for the development of welding, inspection, and alternative weld flaw acceptance criteria, as used for girth welds during pipeline construction is presented. Welding is typically the pace limiting step during pipeline construction and is critical element of pipeline integrity. As such it is vital that it be completed efficiently and with high quality. Each of these three elements is vitally important to welding productivity and quality. At the core of the approach is the coordination of the three elements such that they are developed in concert. By this coordinated effort, all design options are considered leading to optimization of the final outcome. The approach is described by providing an example alternative weld flaw acceptance criteria, and giving the logic pertaining to choices of welding setup, AUT setup, the standard used for design and construction, and the impact of choices within these three elements on the final outcome. The paper illustrates the importance of a unified approach on weld productivity and quality.

Portable Weld Inspection Management System

2007 ◽  
Vol 23 (03) ◽  
pp. 147-160
Author(s):  
Michael J. Ludwig ◽  
Chris Conrardy
Keyword(s):  
Visual Inspection ◽  
Welding Process ◽  
Lean Six Sigma ◽  
Minimum Size ◽  
Inspection System ◽  
Prototype System ◽  
Inspection Method ◽  
Prototype Tool ◽  
Inspection Process ◽  
Weld Inspection

Manual visual inspection is by far the most widely used weld inspection method. A given weld may be visually examined multiple times as parts are joined and made into assemblies. Because visual inspection is somewhat subjective, and prone to error (a typical inspector only identifies about 85% of the visible defects); welds that pass one inspection may fail subsequent inspections, resulting in multiple inspection and repair cycles. This paper discusses a project that tested the benefits and limitations of a semiautomated weld inspection system. The goal of this semiautomated inspection approach is to provide quantitative, nonsubjective quality measurements of welded structures in order to: eliminate redundant inspections, reduce unnecessary multiple repair cycles, avoid repair of welds that meet minimum size requirements, and enable recording of weld size so that overwelding can be identified and reduced. The technology would also allow tracking of weld quality and statistical analysis of welding process capability to support lean/six-sigma continuous improvement initiatives. A prototype system was assembled and field tested by inspecting actual ship structures. The equipment evaluated has potential, but needs both hardware and software modifications before it can be used as a tool on a regular basis in a shipbuilding environment. As is, it will be useful as an audit tool to gauge the health of the visual inspection process and to further document the inherent variability of the visual inspection process. Recommendations were made for improvements to refine the prototype tool prior to broader deployment.

scholarly journals Reliability of Mechanised UT Systems to Inspect Girth Welds During Pipeline Construction

1998 ◽  
Author(s):  
Jan A. de Raad
Keyword(s):  
High Speed ◽  
Ultrasonic Inspection ◽  
Probability Of Detection ◽  
Inspection System ◽  
Present System ◽  
Immediate Feedback ◽  
Long Distance ◽  
Acceptance Criteria ◽  
Actual Use ◽  
Girth Welds

As an alternative to radiography, a field-proven mechanized ultrasonic inspection system is discussed. Called Rotoscan, this system has been developed for inspection of girth welds during construction of long-distance pipelines, both on- and offshore. It is characterized by high inspection speed and instant recording of results. Unlike prevailing radiography, it provides immediate feedback to the welders. Recent technical improvements in flaw sizing and recording have allowed the application of rejection/acceptance criteria for weld defects based on fracture mechanics principles. The development and actual use of such modern acceptance criteria, particularly in Canada, supported the introduction of mechanised ultrasonic inspection. World wide applications proved that, contrary to expectations, ultrasonic inspection does not lead to higher weld repair rates than radiography does. Between early 1989 and now, over 5.000 km of pipeline (300.000 welds) were inspected with Rotoscan and its reliability proven. The introduction of colour enhanced transit distance “C-scan mapping”, producing a coherent picture based on the signal’s transit distance, enabled the system to cope with most existing ultrasonic procedures and acceptance criteria, because of its capability to detect and quantify volumetric defects. Moreover, the integrated simultaneous Time Of Flight Diffraction (TOFD) function enables through-thickness sizing of defect. The present system is capable of achieving a high Probability Of Detection (POD) together with a low False Call Rate (FCR). In the meantime, Rotoscan has been qualified in various countries, for different customers and for a variety of weld processes, pipe diameters and wall thicknesses. Because of its features, the now mature system has demonstrated its capabilities also for use on lay barges as an alternative to high-speed radiography.

Pipeline Girth Weld Inspection and Flaw Acceptance Criteria for Sour Service Applications

2017 ◽  
Author(s):  
Shashi Bhushan Kumar ◽  
Kapil Mohan ◽  
Shaodong Zhang ◽  
Jens P. Tronskar
Keyword(s):  
Best Practice ◽  
Oil And Gas ◽  
Probability Of Detection ◽  
Resistance Testing ◽  
Acceptance Criteria ◽  
Gas Field ◽  
Radiographic Inspection ◽  
Weld Inspection ◽  
Girth Welds ◽  
Sour Service

To establish flaw acceptance criteria for carbon steel pipeline girth welds that are intended to transport sour crude, wet sour gas and condensate it is important to assess the effect of operating environment and strain levels by performing the fracture toughness/ resistance testing as per DNV-OS-F101: 2013 in a representative simulated service environment or under more severe test conditions. None the less many oil and gas field operators still believe that using workmanship criteria and radiographic inspection will be adequate to ensure a safe future operation of the pipeline meeting the design life requirements under sour or severely sour operating environments. Unfortunately, experience shows that this is a dangerous practice as radiography tends to miss out in detecting the most severe planar defects such a lack of fusion, hydrogen induced cracking and weld root centerline cracks, this is specifically so for narrow J-bevel welds. Hence, DNV GL based on experience from many projects advocates inspection of all sour service pipelines using inspection methods such as AUT with a high probability of detection for planar flaws. Further, the AUT acceptance criteria shall be chosen appropriately with due considerations as workmanship type of acceptance criteria without proper verification may result in non-conservatism in the pipeline girth weld inspection and weld sentencing. This present paper presents some recent project experiences from typical sour service subsea pipeline projects and provide advices representing what is considered current best practice for testing and qualification of AUT systems for sour service projects.

On the Evaluation and Consideration of Fracture Mechanical Notch Support Within a Creep Fatigue Lifetime Assessment

2018 ◽  
Author(s):  
Christian Kontermann ◽  
Henning Almstedt ◽  
Falk Müller ◽  
Matthias Oechsner
Keyword(s):  
Fatigue Loading ◽  
Experimental Program ◽  
Energy Market ◽  
Steam Turbines ◽  
Fatigue Lifetime ◽  
Global Strain ◽  
Creep Fatigue ◽  
Main Components ◽  
Flexible Operation ◽  
The Impact

Changes within the global energy market and a demand for a more flexible operation of gas- and steam-turbines leads to higher utilization of main components and raises the question how to deal with this challenge. One strategy to encounter this is to increase the accuracy of the lifetime assessment by quantifying and reducing conservatisms. At first the impact of considering a fracture mechanical notch support under creep-fatigue loading is studied by discussing the results of an extensive experimental program performed on notched round-bars under global strain control. A proposal how to consider this fracture mechanical notch support within a lifetime assessment is part of the discussion of the second part. Here, a theoretical FEM-based concept is introduced and validated by comparing the theoretical prediction with the results of the previously mentioned experimental study. Finally, the applicability of the developed and validated FEM-based procedure is demonstrated.

scholarly journals The impact of subtitled movies on vocabulary development

2017 ◽  
Vol 6 (1) ◽  
pp. 1-6
Author(s):  
Alisa Sadiku
Keyword(s):  
Language Learning ◽  
Vocabulary Acquisition ◽  
Vocabulary Development ◽  
Real Life ◽  
Target Language ◽  
Adequate Knowledge ◽  
Language Environment ◽  
The Right ◽  
The Impact ◽  
Technology Resources

Learning new vocabulary compromises a significant factor for success within language learning since without the adequate knowledge of words and their meaning, learners are not able to use the target language efficiently. Moreover, vocabulary tends to be forgotten if it is not acquired and used through the right methods that will provide learners with language inputs in genuine target language environment. In this regard, the increasing access to different multimedia and technology resources facilitate spontaneous vocabulary acquisition for the contemporary age learners. In particular, movies with subtitles can be a great tool in bringing students closer to authentic real life communication vocabulary. As a result, previous studies have found out several benefits of using subtitled movies by confirming that subtitles indeed improve vocabulary development.

scholarly journals The Impact of Educational Inspection System on Organizational Effectiveness and Individual Sufficiency

2015 ◽  
Vol 03 (10) ◽  
pp. 115-123
Author(s):  
Süleyman Göksoy ◽  
Mahmut Sağir ◽  
Şenyurt Yenipinar
Keyword(s):  
Organizational Effectiveness ◽  
Inspection System ◽  
The Impact

Behavior of Different Corrosion Ratio RC Beams under Fatigue and Monotonic Loads

2010 ◽  
Vol 163-167 ◽  
pp. 3074-3078
Author(s):  
Lei Wang ◽  
Ai Ping Yu ◽  
Bao Chen Liu
Keyword(s):  
Ultimate Load ◽  
Fatigue Loading ◽  
Concrete Cover ◽  
Reinforced Concrete Beams ◽  
Flexural Stiffness ◽  
Rc Beams ◽  
Reinforced Beams ◽  
Monotonic Loads ◽  
The Impact ◽  
Strength And Ductility

This paper present results and discussions on an experiment study on the impact of corrosion ratio to the RC beams under fatigue and monotonic loads. Seven reinforced beams with the same steel type, concrete cover, steel diameter and ratio were test. The effect of corrosion ratio on flexural stiffness of these RC beams was discussed. Based on fatigue and monotonic test for these beams, the most investigated parameters in this experimental study were distortion, stress distribution, ultimate load of corroded reinforced concrete beams. The results indicate that the effect of corrosion ratio on flexural stiffness of RC beams is very obviously, curvatures of corroded beams increase monotonically with degree of corrosion. Fatigue loading has great impact on the performance of corroded RC beams; it can reduce the ultimate strength and ductility of the beams significantly as corrosion ratio increase.

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