The oil and gas industry includes the global processes of exploration, extraction, refining, transportation (often by oil tankers and pipelines), and marketing of petroleum products.
The largest volume products of the industry are fuel oil and gasoline (petrol). Petroleum is also the raw material for many chemical products, including pharmaceuticals, solvents, fertilizers, pesticides, synthetic fragrances, and plastics.
The industry is usually divided into three major components: upstream, midstream, and downstream. Upstream relates to the exploration and extraction of crude oil, midstream encompasses transportation and storage of crude, and downstream concerns refining and marketing crude oil into various end products.