TABLE OF CONTENTS Since offshore pipelines were first installed in shallow waters in the early 1950s, the technical difficulties of operating and maintaining lines in the subsea environment have challenged the industry. Today, these challenges are multiplied as pipelines coexist with busy harbors, industrial ports, commercial and recreational fishing areas, general recreational areas, environmentally sensitive areas, and other offshore facilities. Deep water had been defined as depths greater than 650 ft (the edge of the Outer Continental Shelf) but is now typically considered to be a depth greater than 1600 ft. Offshore pipelines are routinely installed in water depths of up to 7000 ft, as of this writing. Current technology is allowing installation at ever-increasing depths.
In the Outer Continental Shelf waters of the United States, corrosion was the largest single cause of pipeline failures (50%) between 1967 and 1990, with maritime activities accounting for 14% and natural forces 12% of the remaining known causes of 1047 recorded pipeline failures. Interestingly though, almost all of the deaths, injuries, damages, and pollution episodes were caused by damages from vessels [71]. Deaths and injuries are associated with gas pipelines, which, because of the highly compressed flammable gas, have higher explosive potential than most liquid lines. Even though corrosion caused a greater number of leaks, most of the pollution (in volume of spilled product) was caused by anchor damage [71]. In this data sample, therefore, the most prevalent cause was not the most consequential cause. When shallow water accidents are included in the analysis,...
