Petroleum products are used widely in our everyday lives. They are used to power automobiles produce containers and to keep us warm. Petroleum, or crude oil is liquid composed of various organic chemicals. It is found in large quantities below the surface of Earth and is used as a fuel and as a raw material in the chemical industry.
The word petroleum comes from the two Latin words “petro” and “leum” “petro” meaning rock and “leum” meaning oil. The chemical composition of all petroleum is principally hydrocarbons which are a family of organic compounds, composed entirely of carbon and hydrogen. Petroleum is formed under Earth’s surface by the decomposition of organisms.
The remains of tiny organisms that live in the sea are trapped with the sands and silts that settle to the bottom in sea basins. These deposits become the source rocks for the generation of crude oil. The process began many millions of years ago with the development of abundant life, and it continues to this day. The sediments grow thicker and sink into the seafloor under their own weight. As additional deposits pile up, the pressure on the ones below increases several thousand times, and the temperature rises by several hundred degrees.
The mud and sand harden into shale and sandstone and the remains of the dead organisms are transformed into crude oil and natural gas. Surface deposits of crude oil have been known to humans for thousands of years. In the areas where they occurred, they were long used for limited purposes, such as caulking boats, waterproofing cloth, and fueling torches.
By the time the Renaissance began in the 14th century, some surface deposits were being distilled to obtain lubricants and medicinal products, but the real exploitation of crude oil did not begin until the 19th century. The Industrial Revolution had by then brought about a search for new fuels, and the social changes it effected had produced a need for good, cheap oil for lamps; people wished to be able to work and read after dark. Once petroleum forms, it flows upward in Earth’s crust because it has a lower density than the brines that saturate the interstices of the sands and carbonate rocks that constitute the crust of Earth.
The crude oil and natural gas rise into the pores of the coarser sediments lying above. For several years people had known that wells drilled for water and salt were occasionally infiltrated by petroleum, so the concept of drilling for crude oil itself soon followed. The first such wells were dug in Germany from 1857 to 1859, but the event that gained world fame was the drilling of an oil well near Oil Creek, Pennsylvania, by Edwin L. Drake in 1859.
Drake drilled to find the supposed “mother pool” from which the oil seeps of Titusville Pennsylvania were assumed to be emanating. The reservoir Drake tapped was shallow and the petroleum was a paraffin type that flowed readily and was easy to distill. Drake’s success marked the beginning of the rapid growth of the modern petroleum industry. With the invention of the automobile and the energy needs brought on by World War I, the petroleum industry became one of the foundations of industrial society.
Today four main by-products are derived from petroleum. These by-products are oil, coal, gas, and plastics. According to the US Energy Information Administration, in 1998 the United States was the largest producer of coal, producing 23.82 quadrillion BTU. The largest consuming country was China who consumes 22.35 BTU of coal yearly.
The United States was in a close second with 21.67 BTU consumed. Although authentic records are unavailable, historians believe coal was first used commercially in China. In the early 18th century the demand for coal escalated when English iron founders John Wilkinson and Abraham Darby used coal to manufacture iron. An almost insatiable demand for coal was created by successive metallurgical and engineering developments, most notably the invention of the coal-burning steam engine by Scottish mechanical engineer James Watt in 1769.
Until the American Revolution most of the coal consumed by the American colonies was imported from England or Nova Scotia. Wartime shortages and the need to manufacture munitions spurred the formation of small American coal-mining companies that mined Virginia’s Appalachian bituminous field and other deposits. The construction of the first practical locomotive in 1804 in England by British engineer Richard Trevithick sparked a tremendous demand for coal. The growth of the railroad industry and the subsequent rise of the steel industry in the 19th century spurred enormous growth in the coal industry in the United States and Europe.
The widespread use of petroleum as a fuel before, during, and after World War I eventually reduced the demand for coal. The change from coal to oil as fuel in warships in the early 1900s, the switch in the railway industry to diesel-electric locomotive engines in the 1940s and 1950s, and increasing use of natural gas as a heating fuel all contributed to a decline in coal production. Still, electric utilities continued to burn large amounts of coal to produce electricity.
Humankind has been using natural plastics for thousands of years. For example, the early Egyptians soaked burial wrappings in natural resins to help preserve their dead. People have been using animal horns and turtle shells for centuries to make items such as spoons, combs, and buttons. In order to find more efficient ways to produce plastics and rubbers, scientists began trying to produce these materials in the laboratory.
In 1839 American inventor Charles Goodyear vulcanized rubber by accidentally dropping a piece of sulfur-treated rubber onto a hot stove. Goodyear discovered that heating sulfur and rubber together improved the properties of natural rubber so that it would no longer become brittle when cold and soft when hot. In 1862 British chemist Alexander Parkes synthesized a plastic known as pyroxylin, which was used as a coating film on photographic plates.
The following year, American inventor John W. Hyatt began working on a substitute for ivory billiard balls. Hyatt added camphor to nitrated cellulose and formed a modified natural plastic called celluloid, which became the basis of the early plastics industry. Celluloid was used to make products such as umbrella handles, dental plates, toys, photographic film, and billiard balls. These early plastics based on natural products shared numerous drawbacks. For example, many of the necessary natural materials were in short supply, and all proved difficult to mold.
Finished products were inconsistent from batch to batch, and most products darkened and cracked with age. Furthermore, celluloid proved to be a very flammable material. Due to these shortcomings, scientists attempted to find more reliable plastic source materials. The chemistry of joining small molecules into macromolecules became the foundation of an emerging plastics industry. Between 1920 and 1932, the I.G. Farben Company of Germany synthesized polystyrene and polyvinyl chloride, as well as a synthetic rubber called Buna-S. In 1934 Du Pont made a breakthrough when it introduced nylon which is a material finer, stronger, and more elastic than many other fabrics.
After World War II, the pace of new polymer discoveries accelerated. Today, scientists can tailor the properties of plastics to numerous design specifications. Modern plastics are used to make products such as artificial joints, contact lenses, space suits, and other specialized materials. As plastics have become more versatile, use of plastics has grown as well. By the year 2005, annual global demand for plastics is projected to exceed 441 billion pounds.
Natural gas is formed mostly from plankton. These organisms were slowly buried and compressed under layers of sediment. Over millions of years, the pressure and heat generated by overlying sediments converted this organic material into natural gas.
Natural gas is composed primarily of methane and other light hydrocarbons. Natural gas frequently migrates through porous and fractured reservoir rock with petroleum and subsequently accumulates in underground reservoirs. Because of its light density relative to petroleum, natural gas forms a layer over the petroleum. Natural gas may also form in coal deposits, where it is often found dispersed throughout the pores and fractures of the coal bed.
Most oil wells in the United States are drilled by the rotary method that was first described in a British patent in 1844 assigned to R. Beart. Trapped crude oil is under pressure. If it was not trapped by a rock or something of the kind it will continue to move upward until it escaped at the surface of Earth. When a well bore is drilled into this pressured accumulation of oil, the oil expands into the low-pressure sink created by the well bore in communication with Earth’s surface. As the well fills up with fluid, however, a backpressure is exerted on the reservoir, and the flow of additional fluid into the well bore would soon stop, were no other conditions involved.
Most crude oils, however, contain a significant amount of natural gas in solution, and this gas is kept in solution by the high pressure in the reservoir. The gas comes out of solution when the low pressure in the well bore is encountered, and the gas, once liberated, immediately begins to expand. This expansion, together with the dilution of the column of oil by the less dense gas, results in the propulsion of oil up to Earth’s surface.
As fluid withdrawal continues from the reservoir, the pressure within the reservoir gradually decreases, and the amount of gas in solution decreases. As a result, the flow rate of fluid into the well bore decreases, and less gas is liberated. The fluid may not reach the surface, so a pump must be installed in the well bore to continue producing the crude oil. Crude oil is perhaps the most useful and versatile raw material that has become available for exploitation.
By 1998, the United States was using 7 billion barrels of petroleum per year, and worldwide consumption of petroleum was 26.9 billion barrels per year.