Petroleum

Petroleum, “rock oil” or “oil from the earth” (from the Latin petra, “rock” or “stone,” and oleum, “oil”), is a complex mixture of hydrocarbons and other organic compounds. As a technical term, petroleum refers to liquid crude oil as well as natural gas, viscous and solid forms (bitumen), and other petroleum products and possesses a large range of colors and consistencies. In ordinary language, petroleum refers specifically to crude oil. Scientists believe that crude oil (measured in barrels, abbreviated bbls) formed during the past 600 million years in the Earth from the remains of single-celled planktonic animals and plants in ancient seas and lakes. Over time, layers of mud, silt, and sand covered these remains, forming sedimentary rock over them. Geologic heat and pressure from this weight turned the biomass into crude oil and forced it into nearby porous rocks. Several geological elements have to be present for any kind of petroleum to form. These include source rocks that are rich in organic materials to generate petroleum, porous reservoir rocks (such as sandstone) to store the petroleum, and a nonpo-rous trap, such as faults, anticlines, or salt domes, to prevent the petroleum from leaking away. These formations exist at varying depths (mostly between 150 and 7,600 meters [500–25,000 feet]) in the Earth's crust (beneath land as well as offshore). Even though petroleum occasionally reaches the surface through seepages, most of the time, expensive drilling and pumping technologies are necessary to find, extract, and collect it.

Petroleum has been known and used in numerous regions around the world for thousands of [Page 2162]years: People have used it to light lamps, for caulking and waterproofing, for medicinal purposes, or as a fire weapon. New extraction technology resulted from the pioneering work of Edwin Laurentine Drake, who in 1859 innovated the technology of drilling wells on Oil Creek in Pennsylvania (later known as Titusville) by driving down pipes to keep the drill hole from filling in and thereby providing access to deeper oil fields. Kerosene, a petroleum distillate, eventually replaced whale oil for lighting, but there was no large demand for oil until advanced refining techniques and technological inventions created new uses for petroleum. In particular, the invention of gasoline-powered automobiles in 1885 to 1886 by Gottlieb Wilhelm Daimler and Karl Friedrich Benz and their later mass production along assembly lines conceived by Henry Ford around 1913 to 1914 provoked new demand for petroleum as an engine lubricant, and consumers and companies alike pushed for further oil drilling. These dynamics also generated a growing demand for gasoline—originally a by-product of kerosene—to fuel new automobiles. This demand spurred research for new sources and pushed companies to establish extensive distribution networks of gas stations. Thus, petroleum rose to be the most important fossil fuel of the 20th century.

Once they extracted crude oil, investors had to temporarily store, refine, and transport it. They developed cylindrical tanks made from wood or steel to provide storage before shipment or refining. Various designs emerged, with special forms for volatile liquids and other products. (The high flammability of petroleum and its products has led to numerous fires, starting with the early extraction places in Pennsylvania.) Crude oil also has to go through various refining processes, including distillation, which separates the hydrocarbon components from each other and turns the crude oil into usable products. New uses are created regularly and are present (along with autos and engines) in our everyday life, from plastics to lubricants, dyes, drugs, and many synthetic materials. Production sites for these products are often located far away from both refineries and consumers, as it is generally cheaper to move crude oil than the refined product. Railroads were an important early means of transportation, and barges carried oil on inland waterways or along coastal areas. Now supertankers that hold 100,000 to more than 2 million bbls make possible the global transport of oil. Increased maritime traffic puts stress especially on choke points such as the Suez and Panama Canals and the Bosporus Strait, making them important geopolitical sites.

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