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).

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