Drilling for Offshore Oil

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Drilling for Offshore Oil

Overview

Although the first "offshore" oil drilling took place in the mid-1890s, the first true offshore oil rig, out of sight of land, was not built until 1947 off the Louisiana coast. Since that time, offshore and deep-water drilling has become increasingly sophisticated, and oil recovery is taking place in ever-deeper waters on the continental shelf throughout the world. In addition to the Gulf of Mexico, offshore oil rigs have sprouted off the California coast, between Indonesia and Australia, the Caspian Sea, the Mediterranean Sea, and in the North Sea. Near-shore drilling takes place in Venezuela's Lake Maracaibo and, north of Indonesia, in waters claimed by China, Vietnam, and Indonesia lies what may be the world's largest natural gas field. The world has come to depend heavily on offshore oil, in spite of the risk of large-scale marine oil spills, the expense of constructing an oil platform, and the risky nature of the work.

Background

Seeps of oil have been known since antiquity, including some places just off the coast of California. In the mid-1890s, a few oil wells were drilled off a pier near Santa Barbara, but they produced only a few barrels of oil per day. Other oil platforms were built in the next few decades, primarily in lakes in Louisiana and Venezuela, as well as in the shallow waters off the Texas coast. Although more productive than the early Santa Barbara wells, they were still a far cry from true offshore oil rigs.

In 1947, the Kerr-McGee company, an independent Oklahoma-based oil firm, purchased the rights to drill for oil about 10 mi (16 km) off the Louisiana shore. They were fairly sure that the oil was there; what they didn't know was how to build an oil rig that would operate out of sight of land. Hurricanes, possible ship collisions, high waves, uncertain bottom conditions, and more were all important and all unknown. Kerr-McGee solved these problems, and others, and went on to build the first true offshore oil rig, striking oil in 1947. Other companies soon followed suit, although at a deliberate pace because of the high cost of offshore oil recovery (about five times the cost of similar wells on land). Offshore drilling really started to take off in the 1960s, in the Gulf of Mexico and off the California coast. In the 1970s, oil was discovered in the North Sea and, over the next 10 years, in many other locations. By 1980 it was thought that up to a quarter of all recoverable oil could be located at sea, worth over $5 trillion in year 2000 dollars.

Several technological innovations made offshore oil production possible. Among these were methods of finding oil away from any visible geological indicators, oil platform design and construction, getting the oil to shore, and making the platform able to withstand wind, weather, waves, and other possible disasters. All of these challenges were met, of course, as indicated by the presence of numerous oil platforms today.

North Sea oil pushed oil rig technology as never before. Forced to drill in deeper, often stormy waters that experienced a full four seasons, engineers developed a number of innovative solutions. Where the first offshore rigs rested on the bottom, supporting their weight and the weight of long supports, some later rigs were supported by huge hollow floats, tethered to the seafloor with the platform riding high above the waves. Other rigs were constructed ashore and towed to their drilling sites, where the legs were cranked down through the platform to rest on the seafloor. To maximize production, some huge platforms were constructed with 50 or more separate wells beneath them. These, and other technological advances, made it possible to drill for oil in ever-deeper ocean waters.

With increased offshore drilling came greater chances for pollution if something went wrong. The first such "blowout" occurred off the coast of California in 1969, spilling a few thousand barrels of oil into the sea. A more serious blowout occurred in 1979 in the Gulf of Mexico. These events captured the public's attention at the time, but interest seemed to wane quickly, mainly because such events are not common.

Impact

Offshore oil is a significant part of the world's energy picture and shows signs of becoming even more important as the large oil fields on land become depleted. However, their discovery and exploitation has already affected society in some interesting and important ways. These are: 1) Pushing technological innovations that have benefited both the oil industry and science. 2) The addition of an important new source of energy. 3) The economic and political impacts on countries with offshore oil reserves. 4) Influences on the mass media and popular culture.

One of the most obvious issues about drilling for oil at sea is that it's difficult. One person compared it to trying to drill a hole in the sidewalk by dangling a piece of spaghetti from the top of the Empire State Building. As oil rigs moved into deeper water, the engineering problems became ever more challenging, requiring an array of innovative engineering solutions to overcome them. For example, wave stress on deep-water oil platforms in the North Sea has forced engineers to find better ways of monitoring stress-induced cracks in the platform supports. Pulling a drill string to change the bit requires lowering it again to successfully hit a 12- in (30-cm) hole at the bottom of 100 m (328 ft) of water, without being able to see the hole or the end of the drill string. Even prospecting for oil underwater is difficult, requiring whole new systems for conducting geophysical investigations in deep water. Among these systems was the development of new methods of seismic studies, setting off explosions to map underground structures by timing the return of echoes from different rock and sediment layers. All of these innovations have found uses elsewhere, many of them in science.

In 1968, the Glomar Challenger set out on the first leg of the Deep Sea Drilling Project. Using technology largely developed by oil companies, its goal was to conduct drilling operations in the deep ocean to better understand the history of the oceans and the Earth. Other scientific vessels had conducted ocean drilling before, but none had been specially designed for the task. The Glomar Challenger and its successor vessels (currently the JOIDES Resolution) have made a number of extremely important discoveries, including confirmation of many aspects of plate tectonic theory, a better understanding of the origins of ice ages, the recent passage of the solar system through a relatively dense interstellar dust cloud, and the discovery of apparent supernova debris in deep-sea sediments. All of these discoveries have served to give us a far better understanding of the Earth, and factors that can affect it (and us). Would we have made these discoveries without offshore oil platforms? Almost certainly. However, it is likely that the technology to make such discoveries would have lagged without the impetus provided by the desire and the need to recover oil from the depths.

Probably the best-known impact of developing offshore oil rigs is the tremendous impact it has had on the world's energy picture for the short-term and intermediate-term future. It is now thought that at least 25% of the world's oil is to be found at sea. This is a tremendous amount of oil, especially when we consider that most of the large fields ashore are thought to have been located already. Petroleum geologists have covered the Earth's surface in search of promising geologic formation that might house oil and, since the discovery of Alaskan oil, only one large oil field has been added to the picture, the oil near the Caspian Sea. And this is not a new oil field, just one that was underutilized until recently. Many geologists feel that, if there are any huge new oil fields yet to be found, they underlie the oceans. As of this writing, the biggest offshore oil fields are in the Gulf of Mexico, between New Guinea and Australia, and in the North Sea. With probable lifespans of several decades, these major oil fields are an important source of energy for the world.

Offshore oil is also an important source of income for many nations and, since many nations with large amounts of offshore oil are not OPEC members, it is politically important, too. While petrodollars have not had the same impact on Britain, Norway, and the Netherlands that they had on the oil-rich nations of the Middle East, they have proven to be a welcome addition to national coffers. At the same time, it must be remembered that these nations were already established as first-world countries when they discovered their offshore oil, as opposed to the small and then-backward kingdoms of the Middle East. Other nations, particularly the resource-rich but poverty-stricken nations of Venezuela and Indonesia, have failed to capitalize on their oil resources, primarily because oil revenues have been intercepted by the ruling elite where they serve to help maintain the power structure. In addition, since most of these nations are not OPEC members, the development of offshore oil has served to dilute OPEC's power to impose oil prices on the rest of the world. In fact, since North Sea oil recovery became important in the 1980s, OPEC's power dwindled markedly with only a few brief resurgences in the 1990s. This, in turn, has helped keep oil prices down for a remarkably long time and is one of the factors behind the record-setting U.S. economy during the 1990s.

Finally, oil platforms have entered the public arena to some extent because of their size, sophistication, and use of high technology. At least one James Bond movie was set on an oil rig, as were two thrillers written by the late Alistair MacLean. Other books and movies have made use of oil platforms, too, and a number of documentary shows have been devoted in full or in part to these behemoths.

P. ANDREW KARAM