Health & Safety
Hugh Davies discusses how the latest internal weld inspection tools are helping oil and gas companies to verify the quality of risers, fatigue-critical and CRA- clad pipes, as well as curved pipes and manifolds.
Hugh Davies discute cómo las últimas herramientas de inspección de soldadura interna están ayudando a las empresas de petróleo y gas a verificar la cantidad de depósitos, tuberías contra fatiga y chapadas en CRA, así como tuberías y colectores curvos.
Hugh Davies erklärt wie Öl- und Gasunternehmen mit modernsten Werkzeugen zur internen Schweißnahtprüfung die Qualität von Steigrohren, ermüdungsanfälligen und mit korrosionsbeständigen Legierungen ausgekleideten Leitungen sowie gekrümmten Leitungen und Verteilern prüfen.
Pipeline welds: seen, measured, quantified and approved
O
ne of the limiting factors in the lifespan of a pipeline is corrosion. Terefore corrosion- resistant alloy- (CRA)
clad pipe is becoming an increasingly important tool. Te welding process is critical to the successful fabrication of CRA-clad pipes and consequently the ability for the pipeline owner to extend the life of their pipeline. However, the welding process itself is very challenging. Prior to the development of the
WeldChecker internal weld inspection system from OMS, methods of examining the quality of internal welds in detail, from both a visual and a measurement perspective, were inadequate and unreliable. A considerable gap existed in the technology available for measuring the critical features of CRA welds such as HiLo (joint misalignment), weld height, width and lack of penetration or fusion. Te WeldChecker system comprises a high-resolution digital video camera for video inspection and a laser scanner to gather pipe geometry
Fig. 1. (Top) The WeldChecker system comprises a camera for video inspection and a laser scanner to gather pipe geometry across both inner walls near the weld, and across the entire weld.
Fig. 2. (Right) OMS has produced a new version of the WeldChecker, which has the same design concept as a London ‘bendy bus’.
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across both pipe inner walls near to the weld, and across the entire weld. Tis is critical during the pre-qualification tests (PQT) to qualify the welding process, equipment and staff for the project. Tis not only allows the client to develop its process and to fully understand the welding parameters, but also enables them to demonstrate to their customer an unrivalled level of weld information and to show full compliance with stringent pipeline specifications. Te ability to give closure on tough decisions regularly encountered by the welding inspector could prove invaluable in saving time, while also ensuring only the highest quality welds are accepted, leading to longer lifespan. When to use WeldChecker is also an important factor – timing is critical to maximise the benefits of the system. Video-only inspection tends to raise as many questions as it answers, often meaning that pipe joints need to be cut out to mitigate any risks, even if they turn out to be acceptable upon closer inspection later. Ultrasonic testing, although very detailed, can only be performed after the weld has been completed. Tere will have been multiple weld passes before finishing the cap of the weld – and this means that if a flaw is found, many hours of work may have already been wasted. Te WeldChecker is best placed to inspect after the second pass, so if there is a flaw in the root weld, it can be cut out at this point – saving time and money. Another technical challenge is the ability to inspect welds around curved pipes. Many of OMS’ clients use CRA materials on subsea structures, such as PLETs (Pipeline End Terminators) and PLEMs (Pipeline End Manifolds). Tese structures tend to have very tight bends, as little as 1D (1 x diameter) on occasion.
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