Offshore drilling
Offshore drilling involves the extraction of oil and gas from beneath the ocean floor, a process that has gained significance as global reliance on oil has increased. The practice began in the late 19th century, with advancements leading to the development of various drilling technologies like jack-up rigs and semisubmersibles, designed for different water depths. Jack-up rigs, which are mobile platforms supported by legs that rest on the seabed, are commonly used for shallower depths, while semisubmersibles and drillships cater to deeper waters, often exceeding 8,000 feet. Despite technological advancements, offshore drilling poses environmental risks, exemplified by incidents such as the Deepwater Horizon oil spill in 2010, which raised concerns about the ecological impact on marine life and water quality.
The debate surrounding offshore drilling often centers on the balance between energy security and environmental protection. Advocates argue that increasing domestic oil supply can stabilize fuel prices and reduce reliance on foreign oil, while opponents highlight the potential for catastrophic oil spills and their effects on marine ecosystems. Various cleanup methods exist, but none are without their drawbacks, raising questions about the long-term environmental consequences of such operations. As the world navigates its energy needs and environmental responsibilities, offshore drilling remains a contentious and critical topic of discussion.
Offshore drilling
Summary: Offshore drilling is the discovery and extraction of underwater oil and gas resources. Although drilling in lakes and inland seas is offshore drilling, in common usage the term especially applies to oil extraction from beneath the ocean floor.
More difficult than oil extraction on land, offshore drilling has become more important as the world has become more dependent on a large and reliable supply of oil, and it is at the center of an ongoing political debate over the potential environmental hazards posed by oceanic oil extraction.
Underwater drilling began quite early, with submerged oil wells in Grand Lake St. Marys, Ohio, in 1891. Five years later, piers were built extending into the Santa Barbara Channel off California, from which to drill submerged oil wells, and soon thereafter offshore drilling commenced in Lake Erie and the tidal zones of the Gulf of Mexico. As offshore drilling shifted to deeper waters in the mid-20th century, new methods needed to be developed and new equipment built. First came fixed-platform rigs for depths up to 100 feet, then jack-up rigs for depths up to 400 feet, as in the Gulf of Mexico.
A jack-up rig is a mobile platform with supporting legs (usually three) that rest on the seafloor. The platform is towed into position or propelled under its own power, at which point the legs are jacked down onto the seafloor until the rig is at rest. Ballast water added to the weight of the platform drives the legs into the sea bottom so that the weight of operations will not push them down further, and the platform is then jacked up above the level of the water so that an air gap prevents waves, currents, and tides from exerting force on the hull. Today, jack-up rigs are the most common type of mobile offshore drilling rig. They are also used for specialized platforms that act as a base for maintenance work, typically on drilling platforms but also on bridges and offshore wind turbines.
Another type of drilling platform is the semisubmersible, a specialized marine vessel designed for enhanced stability. Semisubmersibles are typically used for drilling in depths greater than 400 feet, where they excel at resisting the pitch and yaw of the forces of large waves. The hull structure can be submerged, and the operating deck is kept well above sea level, connected by structural columns to ballasted pontoons far below. Keeping so much of the structure below the water helps keep it stable, but the vessel is never entirely underwater. Removing ballast water from the hub makes the structure float back up to the surface, a method used by heavy-lift semisubmersibles to submerge most of their structure below the water, position themselves underneath another floating vessel, and then deballast in order to pick the floating vessel up as cargo.
The construction of semisubmersibles has occurred in phases, or generations, because it tends to occur in boom periods, with designs being improved and advanced somewhat each time. There have been six such generations. The first generation of semisubmersibles, built in the 1960s, could be used to depths of 600 feet. Subsequent generations date to 1969–74 (1,000 feet), the 1980s (1,500 feet), the 1990s (3,000 feet), 1998–2004 (7,500 feet), and the current and sixth generation, beginning around 2005, which can be used at depths of up to 10,000 feet. The greatest gains in semisubmersible construction have been realized in the back-to-back boom periods since the 1990s, an indication of the significant financial interest in offshore drilling. Today, major semisubmersibles are in use for offshore drilling in the British North Sea, off the coast of Brazil, in the Norwegian Sea, in the South China Sea, in the Gulf of Mexico, in the Indian Ocean, and off Malaysia.
Drillships
Drillships are ships that have been fitted with an apparatus for oil and gas drilling; they can also be used as a platform from which to perform well maintenance. When not purpose-built to an oil company’s specifications, a drillship is often converted from tanker hulls and equipped with dynamic positioning systems, which helps it maintain position over the oil well. Drillships can handle greater depths than most semisubmersibles—in excess of 8,000 feet—and drillship production accelerated in the 2010s, with a worldwide fleet of 80 ships expected by 2013, compared to fewer than 40 in 2009.
Drillships drill by lowering a drilling riser (a specially equipped thick, low-pressure tube) with a subsea blowout preventer and connecting the apparatus to the wellhead. Because of their independence, size, and speed, drillships make exploratory drilling—the drilling of wells to gather information and establish the presence and extent of oil reserves—a faster process.
Dangers of Deepwater Drilling
Deepwater drilling is offshore drilling at depths of more than 500 feet, the drilling conducted by semisubmersibles and drillships. One reason for the sudden rise in those technologies is that, until recently, deepwater drilling was considered economically impractical compared to the shallow-water drilling of jack-up rigs and other platforms. Rising oil prices and fears of the depletion of existing wells finally led to extensive investment in deepwater drilling during the late 20th century, although during the Deepwater Horizon oil spill of April 20 to July 15, 2010, the United States’ secretary of the interior placed a moratorium on offshore drilling on the outer continental shelf for six months beginning on May 30, 2010. The Deepwater Horizon spill occurred when a wellhead blew out, resulting in 11 deaths, 17 injuries, and approximately 200 million gallons of crude oil (some estimates are higher) released into the Gulf of Mexico. The spill persisted for nearly three months and was not fully sealed until September 19. The full extent of the damage and the length of time until recovery are not yet known; in 2011, oil was found on the seafloor that showed no signs of degradation, and environmental concerns have been raised about the cleaning methods used to deal with the spill.
The 2010 moratorium was itself a return to a norm established by executive order of President George H. W. Bush in 1990. That executive order was not lifted until 2008, when his son, President George W. Bush, called for expanding American oil exploration, both through offshore drilling and by drilling in the Arctic National Wildlife Refuge. Bush’s successor, President Barack Obama, also called for the expansion of offshore drilling on March 31, 2010, only three weeks before the Deepwater Horizon disaster. In 2016 the Obama administration issued new rules regarding offshore drilling, including requirements for well design and increased monitoring and inspection. These rules were intended to prevent another such disaster from occurring.
The most persuasive argument in favor of offshore drilling in the United States is the expected impact on oil prices and the resultant stability in fuel sources, particularly for the American consumer. Oil consumption has gone steadily up since the energy crises of the 1970s. Food and other goods are transported further and consume much more fuel energy in their production than they did 30 years ago. Commuting distances have increased, more students attend college (and more of those who do, do far from home), more households have two or more cars, and the rise of e-commerce has made fuel costs, reflected in shipping charges, a significant factor in the cost of the typical consumer’s purchases. All these factors tie the country’s economic health to fuel costs, even more closely than in the 1970s. Although alternatives to fossil fuels are one solution, they are a long-term solution that requires time to develop; in all likelihood, even an earnest attempt to develop alternative energy sources will require multiple generations before demand can be met sufficiently to shield the economy from oil price spikes and shortages. In the meantime, increasing the supply of American oil offers a greater degree of energy security.
Energy Security Versus Environmental Concerns
Energy security is important not simply for economic reasons but for political ones. Dependence on foreign oil has deep impact on American foreign policy. It encourages diplomatic relations with countries toward which the United States might otherwise be more aloof. It motivates wars in the Middle East in which the country would otherwise have little interest. It encourages taking sides in internal disputes in oil-producing countries, which contributed to the energy crises of the 1970s, when oil-producing countries in the Middle East were unhappy with the nature of Western intervention in the politics of their region.
The environmental concerns, however, are considerable. The Gulf of Mexico and the Atlantic Ocean are vulnerable to hurricanes, and the aftermath of 2005’s Hurricane Katrina, for instance, included 8 million gallons of oil spilled from coastal facilities.
Oil spills harm seabirds and marine mammals, which become coated in the oil, making them less buoyant in the water, less able to insulate themselves, more vulnerable to hypothermia and temperature fluctuations, and more likely to become unable to fly. Attempts to clean themselves result in ingestion of crude oil, damaging their organs, throwing their metabolism and other functions out of balance, and contributing to dehydration. Marine plants and phytoplankton suffer when oil spills cover the water and prevent sunlight from passing through the surface, and oil-consuming bacteria crowd other bacteria out of the ecosystem, a condition that is incredibly difficult to remedy.
There are no perfect methods of oil clean-up. Physical collection, such as skimming, is limited by environmental circumstances; not all of the oil may be on the surface, and calm waters are required for skimming to be effective. Controlled burning can be done only during conditions of low or no wind, and it results in air pollution and harm to local wildlife. Dispersants and other chemical remedies may degrade the oil more quickly but can also simply transfer the oil to other parts of the ecosystem; for example, dispersed oil droplets are able to penetrate deep waters and can kill off coral. The chemical remedies themselves may have harmful effects, many of which are poorly understood. Centrifuge systems, in which oil-tainted water is sucked up, mostly cleansed, and dumped back into the sea, are limited by laws limiting the amount of oil that can be returned to the sea in such a manner, making them feasible only for small spills. The best solution may be chemical solidifiers, which change the oil from a liquid into a rubberlike material that floats on the water and will not be dissolved into it, allowing it to be skimmed fairly easily and efficiently. Solidifiers proved useful in dealing with the Deepwater Horizon spill. Nevertheless, it is possible that there are ecological consequences to the use of solidifiers that are not yet known; if nothing else, their use raises the question of what to do with all the solidified oil.
Bibliography
Deffeyes, Kenneth S. Hubbert’s Peak: The Impending World Oil Shortage. Princeton: Princeton UP, 2008. Print.
Domonoske, Camila. "Obama Administration Issues New Rules for Offshore Drilling." Two-Way. NPR, 15 Apr. 2016. Web. 16 May 2016.
Downey, Morgan. Oil 101. New York: Wooden Table, 2009. Print.
Haerens, Margaret. Offshore Drilling. Detroit: Greenhaven, 2010. Print.
Helvarg, David. "The Shifting Politics of Offshore Drilling." Sierra. Sierra Club, 8 Mar. 2016. Web. 16 May 2016.
Hossain, M. Enamul, and Abdulaziz Abdullah Al-Majed. Fundamentals of Sustainable Drilling Engineering. Hoboken: Wiley, 2015. Print.
Leffler, William L., Richard Pattarozzi, and Gordon Sterling. Deepwater Petroleum Exploration and Production: A Nontechnical Guide. Tulsa: PennWell, 2003. Print.
U.S. National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling. Deep Water: The Gulf Oil Disaster and the Future of Offshore Drilling; Report to the President. Washington, DC: National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling, 2011. Print.