A Collaborative Approach to Root Cause Analysis: With Reference to Suncor Energy Terra Nova Flexible Flowlines and Risers

2015 ◽  
Author(s):  
George Karabelas ◽  
Geoff Redfern ◽  
Brad Jacobs ◽  
Andrew Roberts ◽  
Upul Fernando ◽  
...  
Keyword(s):  
Field Tests ◽  
Root Cause Analysis ◽  
Full Scale ◽  
Acceptance Testing ◽  
Cause Analysis ◽  
Root Cause ◽  
Subsequent Investigation ◽  
Start Up ◽  
Terra Nova ◽  
Full Scale Tests

One riser and two flowline sections installed in the Suncor Energy Terra Nova riser replacement programme were shown to leak during field tests performed after site installation. No hydrocarbon loss occurred nor was there an environmental incident; however, the scheduled production start-up for the pipes was delayed. The pipes were designed and manufactured to comply with API [1] code and had successfully undergone full-scale factory acceptance testing (FAT) at 1.5 times design pressure following manufacture. Investigations confirmed that the leaks in both pipes occurred due to a crack in the polymer (PVDF) barrier within the end-fitting region of the pipe. It was also concluded that the crack in the barrier in these pipes occurred after completion of the FAT and sometime during the transportation, storage and subsequent installation of the pipes in the field. It was identified that the problem in the barrier resulted from an unknown thermo-mechanical loading condition of the pipe during this period, and also related to specific design features of some components in those end-fittings. The TapRoot Root Cause Analysis (RCA) tool was used to guide the investigation effort and consider all available data. Small and full-scale tests were performed to simulate and understand the end fitting design in the environments and conditions experienced during transport, installation and offshore testing. What is presented here is a brief outline of the incident and details of the subsequent investigation. The investigation was conducted over a period of 18 months with the participation of all parties involved in the design, manufacture, installation and operation of the flexibles. This paper summarises the investigation process followed, documents the results, discusses the results and outlines the conclusions and recommendations arising from this investigation.

Root Cause Analysis of Bend Stiffener Failure During Umbilical Full-Scale Fatigue Testing

2016 ◽  
Author(s):  
Krassimir Doynov ◽  
Evyatar Belson ◽  
Hengliang Yuan ◽  
Rune Haakonsen ◽  
Ying Li ◽  
...  
Keyword(s):  
Heat Generation ◽  
Manufacturing Process ◽  
Fatigue Testing ◽  
Root Cause Analysis ◽  
Steel Tube ◽  
Fatigue Tests ◽  
Full Scale ◽  
Cause Analysis ◽  
Root Cause ◽  
Test Failure

Dynamic bend stiffeners are widely used to prevent overbending and achieve the desired fatigue life of umbilicals and flexible pipes by transferring bending moments locally to support structures on floaters. Full-scale fatigue testing of umbilical and bend stiffener assemblies has been historically used to verify umbilicals’ fatigue performance in test lab conditions. Fatigue tests on steel tube umbilicals are usually conducted by testing the critical steel tube component to failure as detected by pressure drop and leakage. During a full-scale fatigue verification test conducted while executing a deep-water project in the Gulf of Mexico a bend stiffener has failed prior to failing the critical umbilical steel tube. This test failure, which is the first one encountered on projects stewarded by ExxonMobil Development Company (EMDC), manifested itself as inner and outer polyurethane (PU) cracks extending between 3 and 9 o’clock along the bend stiffener circumference at two different locations. A root cause analysis has been performed on the test failure based on the findings of the bend stiffener and umbilical dissections and temperature measurements. Two possible failure scenarios were constructed and investigated via finite element analyses (FEA), component adhesion tests, and thorough re-verification of manufacturing process and procedures. The FEA was instrumental in confirming adequate bend stiffener strength, and the likely failure scenario of PU fatigue failure due to overheating caused by high test-strain levels required to accelerate decades long operational loading into 3-month test loading. The FEA has been performed to bound the temperature distribution inside the bend stiffener based on loading conditions and temperature measurements taken during the test. Sequential structural-thermal analysis approach has been adopted by using quasi-static and steady state analyses. Equivalent strain distribution under fatigue loading was obtained through nonlinear structural analysis, and imported as heat source input in the PU material and the thermal model. Linear relationship between the strain rate and the heat generation rate has been used. The hysteretic heat generation model and heat transfer boundary conditions were calibrated by matching temperature results to thermocouple readings positioned at various locations on both the bend stiffener and umbilical during testing. The resulting temperature distributions showed the temperature at the inner crack had exceeded the temperature limit established via PU dogbone fatigue tests. Manufacturing process and procedures have been re-verified by conducting adhesion tests, quality checks and recoating of steel work. The root cause analysis has concluded that the bend stiffener design is fit for service. Three main development opportunities are suggested for industry’s consideration to cover thermal design for operation and flex testing of bend stiffeners with umbilicals or flexible risers: a) testing methodology to establish PU heat generation with strain rate relationships, b) methodology and tools for coupled thermo-mechanical FEA, and c) non-destructive test methods for detection of coating and PU disbondments of finished products, and temperature measurement and profiling that can be used for FEA methodology and tool validation.

Root Cause analysis of SG tube ODSCC indications within the tube sheets of NPP biblis unit A

2011 ◽  
pp. 78-86
Author(s):  
R. Kilian ◽  
J. Beck ◽  
H. Lang ◽  
V. Schneider ◽  
T. Schönherr ◽  
...  
Keyword(s):  
Root Cause Analysis ◽  
Cause Analysis ◽  
Root Cause

Rule Construction and its Execution for Root Cause Analysis

2012 ◽  
Vol 132 (10) ◽  
pp. 1689-1697
Author(s):  
Yutaka Kudo ◽  
Tomohiro Morimura ◽  
Kiminori Sugauchi ◽  
Tetsuya Masuishi ◽  
Norihisa Komoda
Keyword(s):  
Root Cause Analysis ◽  
Cause Analysis ◽  
Root Cause

Root Cause Analysis Techniques Using Picosecond Time Resolved LADA

2014 ◽  
Author(s):  
Dan Bodoh ◽  
Kent Erington ◽  
Kris Dickson ◽  
George Lange ◽  
Carey Wu ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Picosecond Laser ◽  
Root Cause Analysis ◽  
Fault Isolation ◽  
Time Resolved ◽  
Cause Analysis ◽  
Root Cause ◽  
Design And Manufacturing ◽  
Multiple Interactions ◽  
Established Technique

Abstract Laser-assisted device alteration (LADA) is an established technique used to identify critical speed paths in integrated circuits. LADA can reveal the physical location of a speed path, but not the timing of the speed path. This paper describes the root cause analysis benefits of 1064nm time resolved LADA (TR-LADA) with a picosecond laser. It shows several examples of how picosecond TR-LADA has complemented the existing fault isolation toolset and has allowed for quicker resolution of design and manufacturing issues. The paper explains how TR-LADA increases the LADA localization resolution by eliminating the well interaction, provides the timing of the event detected by LADA, indicates the propagation direction of the critical signals detected by LADA, allows the analyst to infer the logic values of the critical signals, and separates multiple interactions occurring at the same site for better understanding of the critical signals.

Root Cause Analysis for Pin Leakage

2016 ◽  
Author(s):  
Zhigang Song ◽  
Jochonia Nxumalo ◽  
Manuel Villalobos ◽  
Sweta Pendyala
Keyword(s):  
Failure Analysis ◽  
Root Cause Analysis ◽  
Advanced Technology ◽  
Process Step ◽  
Cause Analysis ◽  
Hard Mask ◽  
Technology Node ◽  
Root Cause ◽  
Tools And Techniques

Abstract Pin leakage continues to be on the list of top yield detractors for microelectronics devices. It is simply manifested as elevated current with one pin or several pins during pin continuity test. Although many techniques are capable to globally localize the fault of pin leakage, root cause analysis and identification for it are still very challenging with today’s advanced failure analysis tools and techniques. It is because pin leakage can be caused by any type of defect, at any layer in the device and at any process step. This paper presents a case study to demonstrate how to combine multiple techniques to accurately identify the root cause of a pin leakage issue for a device manufactured using advanced technology node. The root cause was identified as under-etch issue during P+ implantation hard mask opening for ESD protection diode, causing P+ implantation missing, which was responsible for the nearly ohmic type pin leakage.

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