The oil & gas industry includes the global processes of exploration, extraction, refining, transporting (often by oil tankers and pipelines), and marketing oil & gas products. The largest volume products of the industry are fuel oil and gasoline (petrol). Oil & gas (oil) is also the raw material for many chemical products, including pharmaceuticals, solvents, fertilizers, pesticides, and plastics. The industry is usually divided into three major components: upstream, midstream and downstream. Midstream operations are usually included in the downstream category.
Oil & gas is vital to many industries, and is of importance to the maintenance of industrial civilization in its current configuration, and thus is a critical concern for many nations. Oil accounts for a large percentage of the world’s energy consumption, ranging from as low of 32% for Europe and Asia, up to a high of 53% for the Middle East.
Other geographic regions’ consumption patterns are as follows: South and Central America (44%), Africa (41%), and North America (40%). The world consumes 30 billion barrels (4.8 km³) of oil per year, with developed nations being the largest consumers. The United States consumed 25% of the oil produced in 2007. The production, distribution, refining, and retailing of oil & gas taken as a whole represents the world’s largest industry in terms of dollar value.
Governments such as the United States government provide a heavy public subsidy to oil & gas companies, with major tax breaks at virtually every stage of oil exploration and extraction, including for the costs of oil field leases and drilling equipment.