Abstract

Pipe material specifications and possible future requirements are discussed.

Recent trends in design principle are examined, in particular, the attempts to prescribe fatigue life of pipelines in service, and the acceptance of some degree of plastic strain.

A brief review is given of problems which have arisen in the design and construction of pipelines for arctic conditions and the hostile deep waters of the central and northern North Sea, and measures which are being taken to overcome them.

Recent application of safety measures and environmental conditions is discussed.

Résumé

On traite des spécifications sur les materiaux de pipelines et des besoins futurs possibles.

On examine les tendances récentes dans les principes de conception, en particulier les efforts que l'on a fait, pour établir la durée de vie limitée par la fatigue des pipelines en service, et l'acceptation d'un certain degré de contrainte plastique.

On donne un aperçu sur les problèmes que l'on a rencontrés dans la conception et la construction de pipelines destinés à résister aux conditions arctiques et aux eaux profondes et hostiles de la Mer du Nord centrale et septentrionale, et sur les mesures que l'on prend actuellement pour les résoudre.

On traite aussi de l'application récente de mesures de sécurité et des conditions de l'environnement.

1. INTRODUCTION
2. MATERIALS General

None of the potential alternative materials for line pipe have made significant inroads into the almost exclusive use of steel. They appear unlikely to do so in the foreseeable future, unless there is a substantial improvement in their economic viability relative to steel for equivalent duties.

In the light of past experience we must approach forecasts of the future scale of steel pipelines with some trepidation. One pipeline of 2.5 m dia. is under design in the USSR. Other factors would indicate, however, that this is exceptional and the bulk of future demand will be for pipe diameters within the capacity of most modern mills. There may well be, however, an increase in demand for thick wall pipe at large diameters for submarine line applications. High energy costs and the higher construction costs necessary to install satisfactorily lines of high diameter to wall thickness ratio are likely to limit the economic advantage which may be gained from thin walled high tensile strength pipe for land lines.

It is not possible within a paper such as this to cover all the developments which have taken place in the pipeline industry over the four years which have elapsed since the last World Petroleum Congress in Moscow in 1971. Manufacturers of the wide range of equipment used within the industry will, quite rightly, claim that their products are under constant development. Pipeline Operators have their operation and maintenance procedures under constant review.

The intention

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