A Look at Oil Reserves Around the World

An oil atlas

Proven reserves

Petroleum, whose name comes from the Latin “petra,” or rock, and “oleum,” or oil, seeps naturally to the Earth’s surface along fault lines and cracks in rocks, where it pools. How oil forms and where it is found:

World total 1.3 trillion barrels

267

178

Saudi Can. Arabia

Main oil and gas fields As of 2007 Oil Gas

Top countries, in billions of barrels, 2009

What are proven reserves?

136

Estimated amounts of crude oil that can reasonably be recovered from known reservoirs

Iran

115

104

99

98

60

44

36

Western Europe

Charts show percent of world total by region

21

16

15

13

12

11

7

9

6

Kuwait U.A.E. Libya U.S. Qatar Algeria Angola India Iraq Venezuela Russia Nigeria China Brazil Mexico Norway

3 U.K.

Eurasia

1%

7%

North America

16% Much of N.A.

reserves are located in oil sands in Alberta, Canada

Origins of fossil fuels Most geologists believe oil and natural gas derive from the fossils of microscopic animals and plants, such as algae and plankton, that lived in lakes and seas millions of years ago 1

Tiny marine life died and fell to the sea and lake floors; over time, it was covered with layers of sand and mud, forming a sedimentary basin

2

Over millions of years, accumulated layers of sediment covered the decaying matter, burying it deeper and deeper

3

Higher pressure and temperature nearer the Earth’s center transformed organic matter into hydrocarbons, long chains of carbon and hydrogen atoms

4

Temperatures of 140 F to 212 F (60 C to 100 C) led to formation of crude oil, which contains larger hydrocarbons, such as hexane and octane • Temperatures above 302 F (150 C) helped transform oil into natural gas, which has smaller hydrocarbon molecules, such as methane, propane and butane

A rock, a reservoir and a seal

Almost one-fifth of U.S. reserves – about 4 billion barrels – found in offshore fields in the Gulf of Mexico, most of that in deep water

Pacific Ocean Asia

2.5% Middle East

Atlantic Ocean

56%

Latin America

9%

Africa

8.5% Indian Ocean

Water surface

Anatomy of deep-water reservoirs: The Gulf of Mexico Since rivers can carry large amounts of sediment offshore, many sedimentary basins formed near river deltas, such as the Mississippi Delta Ocean floor

Underwater reservoirs Some of these reservoirs are located thousands of feet below the ocean floor

Where river sediments and coastal waters meet, the river slows down and sediment drops to the ocean floor; lighter particles can drift long distances before settling

Reservoirs

Sandstone

Salt

Oil and gas are found in sedimentary rock; as they form, they rise through layers of porous rock; much of the world’s oil and gas disappears naturally through this process

If sedimentary particles mix with organic debris, the process of forming hydrocarbons starts in the Gulf of Mexico, some of the oil and gas that formed is trapped by salt, rock-like crystalline structures, forming oil/gas reservoirs

© 2010 MCT Graphic: Pat Carr, Lee Hulteng

Land

Ocean

Sometimes, oil and gas migration is blocked by a layer of impermeable rock, which acts like a seal

Trapped oil

Hydrocarbons become trapped and accumulate in porous rock below, forming a hydrocarbon reservoir Reservoirs, once discovered, can be turned into oil and gas fields Source: U.S. Energy Information Administration, Energy Training Resources, International Association of Oil and Gas Producers, Americian Petroleum Institute, Jackson School of Geosciences at University of Texas

Abyssal plains Can be flat or mountainous, with deep canyons and valleys; oil reservoirs found below this floor

Continental drop Steep drop ending in abyssal plains, 1.8-3 miles (3-5 km) below sea level

Continental shelf Beach extends from shore into ocean