Offshore oil was first explored and produced at Baku in the then Russian Empire at the beginning of the twentieth century. About the same time the discovery of onshore oil in Texas and Louisiana induced enormous changes in the economy of that region, making it not only a centre of oil production but also a centre for oil field services and equipment. The oilfield was and is a demanding environment for people and equipment, requiring extraordinary organisation of people and use of technology. We normally think of efforts such as the space programme spinning off technology, but the oilfield has done so as well, in ways that may not be as obvious to ordinary consumers but which are equally beneficial.

The move offshore in the Gulf of Mexico for the oil industry started after World War II. It started in the coastal areas of Louisiana, where land and sea tend to run together. The further out things went, the larger the platforms and the equipment needed to install them.

In this presentation we will concentrate on the Gulf of Mexico mainly because it is here where Vulcan's foray into offshore oil construction first came, although both the industry and Vulcan were worldwide in scope.

Conventional Platforms

When we speak of "conventional platforms" we mean those which have a continuous rigid structure from the sea bed to the ocean surface. These were developed for water depths generally not exceeding 300 m, although a few exceed that in depth. These are generally tubular structures using large diameter pipe, much of which was rolled from plate at the yard and butt welded before being welded into the platform. The coping and sheer size of these structures--some of which were as tall as the original World Trade Centre in New York--required very specialised and competent fabrication capabilities.

Much of the construction portion of the offshore oil industry in the Gulf was centred in Morgan City, LA. The upper right inset above shows platforms being built in yards along the Bayou Boeuf south of Amelia, LA. Most conventional platforms were prefabricated onshore. They were then floated down the bayou and past Morgan City (shown in the lower middle inset above) into the Atchafalaya River and then into the Gulf. (Click here for information on how we got the chart.)

Helicopters were indispensable in offshore exploration, drilling, construction and production, especially as platforms went further and further offshore. Like everyone else offshore, Vulcan personnel spent time in helicopters, enduring mechanical problems (which are potentially disastrous in a helicopter) and violent weather.

After the piling was complete and the piles grouted to the jacket, the actual superstructure of the platform was installed. With the long work season in the Gulf and other tropical and sub-tropical regions, the superstructure was brought out in modules and assembled as shown below. Again the North Sea's hurried schedules forced the development of bringing out the entire superstructure in one piece and setting it on the jacket; this more than anything drove the construction of the very large derrick barges by McDermott and Heerema in the late 1970's and early 1980's. The superstructure had to be as light as possible, not only for lifting but for the structural economy of the platform. The question, "too much weight topsides?" was more than a personal one for designers of conventional platforms.

When we think of a platform, we usually think of a single structure, but many platforms were in reality complexes of structures joined together into small offshore cities. The 1968 photo below shows the last module for such a structure about to be placed on the deck of the platform. Such complexes were not unique to the Gulf of Mexico; they also appeared in the North Sea and other places around the world.