Top 5 Most Desired Offshore Oil Reserves

Looking back 500 million years, prehistoric oceans teemed with microscopic organisms. These tiny plants and animals floated through the seas, driven by cooling temperatures and an atmosphere rich in oxygen. Today, humans, who evolved from these ancient waters, rely on a key byproduct of this era: petroleum.

Over millions of years, vast amounts of plankton lived and died, their remains settling on ocean floors. Covered by mud and sediment, these organic deposits were transformed by heat and pressure into underground reserves of oil, natural gas, and oil shale.

Today, Earth's petroleum reserves lie beneath thick rock layers, with many located underwater. Despite a century of advancements in extraction technology, new offshore reserves are still being discovered. Environmental regulations, treaties, and technological limitations keep some of these resources untapped. Yet, in a world consuming over 80 million barrels daily, the potential wealth of these inaccessible regions remains a focal point [source: CIA].

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According to the United Nations' Law of the Sea treaty, a nation can claim up to 200 nautical miles of coastal waters from its shoreline. This limit can extend to 350 nautical miles if the area is proven to be part of the country's continental shelf by May 2009. The continental shelf refers to the underwater slope that transitions from land to the deep ocean.

Oil companies are eager to tap into the ocean's vast, unexplored fossil fuel reserves. In this article, we explore the top five offshore petroleum reserves they are most eager to exploit.

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5: Protected U.S. Coasts

The U.S. leads the world in oil consumption, using over 20 million barrels daily [source: CIA]. Global oil market instability has sparked nationwide anxiety and become a key issue in political campaigns. Critics argue that oil supply concerns influenced the U.S. military's involvement in Iraq. Ironically, some of the most sought-after oil reserves are located along U.S. coastlines.

According to the U.S. Department of the Interior, approximately 18 billion barrels of undiscovered oil and 76 trillion cubic feet of natural gas may lie beneath the nation's outer continental shelf (OCS). This shelf extends from 3 to 9 nautical miles offshore to 200 nautical miles or more, depending on the continental shelf's reach. The nearest 3 to 9 miles belong to individual states.

What prevents oil companies from tapping into these promising underwater reserves? For one, certain coastal waters are designated as national marine sanctuaries to protect marine ecosystems. Additionally, much of the OCS is safeguarded by federal laws prohibiting offshore drilling. States like Florida also enforce bans in their waters, citing environmental and tourism-related reasons.

Offshore drilling is still active in U.S. waters, with petroleum companies leasing 68 million acres of offshore land. Prime drilling locations include the eastern Gulf of Mexico and Alaska's coastal regions, both hotspots for oil exploration. Some leases in restricted areas were established before the federal drilling ban took effect.

Amid soaring gas prices, numerous politicians are urging Congress to repeal the 1981 federal ban on offshore drilling. In the summer of 2008, President George W. Bush revoked the executive order prohibiting offshore drilling, an order initially strengthened by his father, President George H. W. Bush in 1990 and extended by President Bill Clinton until 2012.

Even if Congress approves, oil companies may gain access to these reserves, but a significant price drop is unlikely. The U.S. Department of Energy predicts that new drilling efforts wouldn't affect the economy until 2030. Establishing a functional oil rig at a promising site is a lengthy process. Experts caution that, even after years of production, the economic benefits might remain limited.

Not all of the world's most desirable petroleum reserves have been shielded by protective laws for years. In Brazil, a major oil field recently emerged on the radar.

4: Brazilian Coasts

Discovering new offshore petroleum reserves is no easy feat. Most of the world's oil and natural gas lies buried between 500 and 25,000 feet (150 to 7,620 meters) beneath layers of soil and rock. Occasionally, oil seeps through the ocean floor and can be identified using specialized sniffer devices. However, survey teams typically rely on advanced seismic and magnetic equipment to detect subtle anomalies in the Earth's crust. These efforts cost billions, and even then, exploratory drilling is often necessary to assess a site's profitability.

When these investments yield a significant offshore oil reserve, the rewards can be enormous. In 2007, Brazil's national oil company, Petrobras, struck gold with the Tupi field, uncovering an estimated 5 to 8 billion barrels of oil and gas [source: BBC News]. This discovery secured Brazil's position as the fourth most promising offshore oil region.

The Tupi field is situated approximately 155 miles (250 km) off Brazil's southern coast in the Santos basin, part of a larger geological complex that includes the Campos and Espirito Santo basins. Experts estimate these reserves could contain between 50 and 100 billion barrels of oil [source: IPS News].

When combined with Brazil's existing 13.8 billion barrels of reserves, these findings could propel the country into the ranks of the world's top 10 oil producers, alongside nations like Kuwait and Venezuela [source: IPS News].

To achieve this status, Brazil must first invest billions in constructing the necessary infrastructure for full-scale production, a challenging task given the depth and density of the petroleum deposits.

Ownership of the Santos, Campos, and Espirito Santo basins is straightforward, as these areas lie within the boundaries allowed by the U.N.'s Law of the Sea treaty. However, disputes arise when potential oil fields are discovered in more contested waters.

In the next section, we'll journey to the North Pole to explore another critical region.

3: The Arctic

For the first time in history, ships can now sail around the Arctic. Over the past century, human consumption of fossil fuels has increased greenhouse gases, leading to rising global temperatures. As Arctic ice continues to melt, new areas become accessible for exploration and potential oil production.

A recent United States Geological Survey suggests that up to 20% of the world's undiscovered oil and gas reserves may lie in the Arctic. This amounts to approximately 90 billion barrels of oil and 1,670 trillion cubic feet of natural gas [source: New York Times]. However, determining ownership of these resources is far from simple.

Under the 17th-century Freedom of the Seas doctrine, the Arctic was considered international territory. However, the United Nations' Law of the Sea treaty grants Canada, Denmark, Norway, Russia, and the United States legal claims to significant portions of the Arctic seabed. Each country has exclusive economic rights to waters extending 200 nautical miles from their coastlines, placing much of the Arctic's resources under U.S. and Russian control.

The U.N. treaty also permits these nations to claim additional territory if they can prove their continental shelves extend into the Arctic seabed. Consequently, all five countries have launched extensive surveys to strengthen their claims and secure a larger share of the Arctic's oil reserves.

One major point of contention is the Lomonosov Ridge, which spans the Arctic between Greenland and Russia. Russia asserts it is an extension of the Asian continental shelf, while Canada and Denmark argue it belongs to North America. In 2007, Russia made a bold move by planting a flag on the seabed beneath the North Pole, a region it could claim if the U.N. supports its case. Russia's Institute of Ocean Geology plans to submit its findings by 2010, leaving the area in dispute until then.

Feeling left out of the Arctic oil race? Don't fret—there's another icy frontier at the opposite end of the globe waiting to be explored.

2: Antarctica

Antarctica, the planet's southernmost continent, is one of the most extreme environments on Earth. With no indigenous population, it wasn't until the last century that humans established research stations and began asserting territorial claims.

Seven nations currently have formal territorial claims in Antarctica: Argentina, Australia, Chile, France, Great Britain, New Zealand, and Norway. Some of these claims overlap, such as Great Britain's, which conflicts with those of Argentina and Chile. The United States, Russia, and others neither recognize these claims nor make their own. The Antarctic Treaty of 1959 designates the entire continent for scientific research only.

During the 1970s energy crisis, oil companies advocated for exploring Antarctic petroleum reserves. In the 1980s, scientists identified significant offshore oil deposits, particularly in the Weddell and Ross Sea areas, estimated at 50 billion barrels [source: DOE: EIA]. To prevent exploitation and environmental harm, the 1991 Madrid Protocol was signed, imposing a 50-year ban on mining and drilling. Even accidental discoveries during research cannot be legally exploited.

Although the Madrid Protocol remains in effect until 2048, some countries are already planning for the future. Great Britain is preparing a "claim in name only" under the U.N. Law of the Sea treaty for waters adjacent to its Antarctic territory. British officials state this is a precautionary measure to protect their interests should the ban on mineral and petroleum extraction be lifted. If approved, this claim would encompass over 360,000 square miles (932,396 square km) of seabed.

However, treaties aren't the sole barrier to accessing these oil reserves. Technological limitations also play a significant role.

1: Ultra-Deep Waters

The first offshore drilling platform was built in 1897 at the end of a pier. In less than a century, oil rigs advanced to operate far from land and reach depths unimaginable in the 19th century. While technology continues to progress, many untapped oil reserves remain beyond our current capabilities.

Today, deep-sea spar platforms can drill to depths of 10,000 feet (3,048 meters), while Transocean drill ships can reach 12,000 feet (3,658 meters) [source: USA Today]. For comparison, the deepest point in Earth's oceans, Challenger Deep, lies 35,840 feet (10,924 meters) below sea level in the Pacific Mariana Trench—over a mile (1.6 km) deeper than the height of Mount Everest.

Drilling at depths of 10,000 feet or less poses numerous challenges. These sunless waters are near freezing, endure crushing pressures, and face strong deep-sea currents. Engineers must design equipment capable of withstanding these harsh conditions, as well as the unique challenges posed by the oil reservoirs themselves.

Thousands of feet below the ocean floor, petroleum reservoirs can reach temperatures of 400°F (204°C) and pressures up to 20,000 pounds per square inch [source: USA Today]. When this hot oil encounters the cold seafloor environment, it can solidify instantly, potentially damaging pipes. While antifreeze has been effective so far, more advanced solutions are being developed [source: Wired].

Despite these difficulties, ultra-deepwater fields hold immense value for oil companies. One notable area is the Lower Tertiary in the Gulf of Mexico, where promising drill sites have been identified at depths of 15,000 to 30,000 feet (4,572 to 9,144 meters). Chevron's Tahiti field in this region is estimated to contain 400 to 500 million barrels of oil [source: USA Today]. The entire Lower Tertiary region may hold up to 15 billion barrels [source: Wired].

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