ABSTRACT:

Some of the most important issues for offshore pipeline operators are "how can I extend the life of the asset", "how can I increase capacity", "how can I prevent leakage or spills without impacting on production" and "how can I best use inspection data?" For offshore pipelines the dominant degradation that impacts on these questions is predominantly Internal Corrosion. Internal corrosion for offshore lines generally arises from production fluids, well contamination, processing the product prior to export, microbiological matter produced, or changing well fluid properties. To meet the needs of the questions above, determination of accurate corrosion growth rates is imperative. The growth rates are then an important input parameter into any corrosion management strategy. Such data can dictate the mitigation measures required to control the corrosion and thus increase asset value. Although corrosion is important, other failure modes are incorporated and maintenance activities are applied to reduce or mitigate against their impact. For example, sea-bed movement, spanning, buckling, dropped objects, trawl board and anchor damage etc. One means of assessing these impacts is to conduct Quantitative Risk Assessments to quantify the probability and consequence of failure. Risk is easy to calculate if you have all the inputs. These inputs can be spread diversely throughout the organisation. Therefore, the accuracy and accessibility of necessary data is key to any risk assessment. This paper presents the technologies and the assessment of corrosion damage, the determination of corrosion rates from in-line inspections and how this can be incorporated into a quantitative risk assessment. A system of integrated data management is presented as a solution to simplify risk calculation, as a repository for all data, and as a means of planning future maintenance activities.

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