Abstract

The paper reviews the parallel developments of the flexible pipe technology and of the subsea industry. It analyses the key characteristics which have made this development possible and which are, basically, flexibility, modularity and versatility. This has allowed the flexible pipe not only to stick to the market, but even to make it possible, as it is an element without which floating production systems would hardly exist. As a result, flexible pipes are now natural components of most subsea developments.

Introduction

The contribution of flexible pipes to subsea developments was recognized in 1995 in this very forum, under the form of an award for "distinguished contribution to the development of subsea oil and gas technology", which, in itself, justifies the title of this paper. However, when the flexible pipe was first conceived, this was not a foregone conclusion.

The history of technology is full of inventions which turned out to be successful in ways their inventor had not always foreseen. Flexible pipe technology is a good example of this. The award came more than 25 years after the concept was developed by the French Petroleum Institute (IFP), and it is ironic to reflect that, initially, the product was not aimed at the subsea industry which, anyway, was still in its infancy at the beginning of the seventies but at drilling technology. This pplication was not a success, so that in 1972 the flexible pipe was really a product without a market.

The purpose of this paper is, beyond briefly recalling the history of the technology, to explain why flexible pipes answered the challenges of subsea developments and how the adequation of the product to the market was maintained as the range of applications was extended. The most interesting question for the future is whether this fit between a product and a market will persist as the subsea industry evolves. This will be discussed in the last section.

Historical milestones

The first flexible pipes where built in the early seventies to replace the steel stems traditionally used for drilling. The ambitious objective was to eliminate the time-consuming manipulation of drilling stems which is required whenever the drilling head has to be changed. The idea was interesting, and the first trials were relatively successful, but the torsional properties of flexible pipe were too low and the pipes were quickly and easily damaged. There was no hope that this technique could replace the current, field-proven methods and the idea was abandoned. In the meantime, Elf needed a short flowline in West Africa, on the Emeraude field, in order to transfer crude oil between two platforms. This is when the application of flexible pipes to the offshore oil industry was first considered and implemented, in 1973. However, this market remained somehow anecdotal and the number of applications limited.

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