As part of an ongoing pipeline technology program for BP Alaska, a 1 km, 48-inch diameter, X100 demonstration pipeline was constructed and operated for a period of two years. Artificial defects were introduced into one of the two test sections. These defects were intended to demonstrate that current assessment methods could be used to predict the behaviour of pipeline defects in a very high strength steel under realistic conditions including accelerated pressure cycling and a range of cathodic protection levels. The defects included in the trial were volumetric corrosion, mechanical damage, arc strikes and girth weld defects. The volumetric corrosion defects included both isolated defects and pairs of interacting defects. All the defects and details such as the girth welds were assessed for fatigue failure in addition to failure at the Maximum Operating Pressure. This paper describes the design of the defects for the trial. The defects were designed to be close to failure, so as to provide a realistic test of the predictive methods. Current methods were used including the Pipeline Defect Assessment Manual (PDAM) and ongoing work sponsored by PRCI.

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