ABSTRACT

Combining their specific knowledge in the fields of lightweight materials technologies and the oil industry, Aerospatiale and l' Institut Francais du Petrole (IFP) have been conducting research and development programmes on high performance composite tubes for offshore applications since 1978. Their experience in terms of research and development achievments, technical alternatives and cost effectiveness is addressed in this paper.

The technica1 aspects are introduced through a series of typical oilfield tubular applications describing design and test results. Advantages and potential cost savings resulting from the replacement of a conventional steel riser by a composite riser are analysed for a TLP in different water depths, combining the effects on cost of top tension, deck weight, hull size and mooring loads.

INTRODUCTION

With ever deeper waters, hostile and remote locations, the oil industry has always managed to adapt the offshore technology to new working conditions and design requirements, pushing back its own frontiers.

During the last decade, offshore activities have grown fast, large capital and production costs being by that time offset by high crude price. In today's situation, development of offshore oil and gas reserves is a challenge demanding new technologies and materials to offer greater simplicity and higher reliability at a lower cost. To face such a challenge, lightweight, high performance composite tubes derived from aerospace techno logy offer one possible alternative.

On drilling or product ion floating un its, the use of these composite materials results in a significant reduction in the equipment weight and deck load which then allows further reductions in the amount of material in the colunms and pontoons of the platform.

In addition, excellent fatigue properties, capital and operating cost savings work in favor of these materials for future offshore applications.

OBJECTIVES

Composite materials made from carbon fibres and/or glass fibres set in resin have been in current use in the aerospace industry for many years. A joint research and development programme on high performance composite tubes was started in 1978 to study tubes made from these materials for specific applications in the oil industry. The main objectives of this research effort were as follows:

  1. to create a suitable design of advanced composite tubes, including end couplings,

  2. to develop a reliable manufacturing process for length up to 25 m (80-ft) and for large diametres,

  3. to demonstrate the general feasibility and good behaviour of composite tubes by a great variety of tests; static, dynamic fatigue, ageing, temperature, etc,

  4. in the case of weight sensitive structures to substitute current tubular goods by advanced composite materials.

TECHNOLOGY

High performance composite tubes are composed of several layers with independant functions. Structura1 1ayers made of high resistance fibres set in a resin matrix, are filament wound and consist of circumferential layers, perpendicular to the tube axis, to resist bursting stresses and longitudinal layers, helically wound, to resist axial forces.

This content is only available via PDF.
You can access this article if you purchase or spend a download.