Developments in Composite Structures for the Offshore Oil Industry
Authors: Williams J.G. 
Published: October 2008

Approximately 25 percent of the oil produced in the world and 14 percent of the oil produced in the United States comes from offshore. Exploratory drilling has been conducted at water depths up to 7500 feet, and future developments in deep water in the Gulf of Mexico and elsewhere hold great promise for adding to reserves. Composite materials promise to provide an important enabling technology to help safely and economically develop and produce deep-water oil and gas reservoirs. Current composites applications offshore are limited to fiberglass components such as gratings and low pressure pipe; however, several advanced composites applications are under developments including risers, 1LP tethers, drill pipe, mooring lines, and high pressure tubing. The assets of composites, including corrosion resistant, weight savings, fatigue resistance, and design flexibility, also translate into cost savings if components with high potential for payoff are chosen, clever design concepts are proposed and developed and low-cost manufacturing processes are utilized. The ability to tailor stiffness, strength, thermal expansion, and other properties has important benefits for offshore operations as discussed in the paper.

INTRODUCTION

The ability to economically recover oil in deep water could be strongly enhanced through the use of innovative structural concepts incorporating composite materials. Four assets make composites important to the offshore oil industry:corrosion resistance,light-weight,fatigue resistance andthe ability to tailor the structural and mechanical response.

Corrosion damage and its control is a multibillion dollar annual expense, and the oil industry is rapidly accepting corrosion resistant composite components for a variety of applications ranging from gratings to fire water pipe. Composite materials, including graphite, Kevlar, and fiberglass offer the potential to reduce substantially the weight of offshore platforms, address fatigue problems, and reduce maintenance costs. The weight of the platform is important in deep water, and fatigue is also an important structural design constraint. In deep water, the weight of a conventional fixed jacket platform increases exponentially with water depth which has motivated the development of innovative light-weight design concepts such as the tension leg platform and moored compliant structures. The onshore oil industry has used fiberglass composites for over 25 years, and several advanced composite components have been studied for offshore application in recent years [1-8]. As background for some of the opportunities for composite materials, the paper presents a short description of modern oil industry technology developed to extract oil and gas from offshore reservoirs. This is followed by a description of recent research and development activities using composite materials to address unique offshore oil industry requirements.

OIL INDUSTRY ADVANCED TECHNOLOGY

A pictorial snapshot of some of the activities which occur offshore is presented in Figure 1. The oil industry is a highly sophisticated industry utilizing many modern technology advancements in materials, electronics, computers, remotely operated vehicles, and communications. The modern offshore platform may produce oil and gas from 30 or more wells with well heads located on the platform as well as from subsea wells located as far remote as 30 miles from the platform.