Petroleum Essay Research Paper Petroleum or crude

Petroleum Essay, Research Paper

Petroleum, or crude oil, is a naturally occurring oily liquid composed ofvarious organic chemicals. It is found in large quantities below the surfaceof the earth and is used as a fuel and as a raw material in the chemicalindustry. Modern industrial societies use it primarily to achieve a degreeof mobility on land, at sea, and in the air that was barely imaginableless than a hundred years ago. In addition, petroleum and its derivativesare used in the manufacture of medicines and fertilizers, foodstuffs,plastic ware, building materials, paints, and cloth and to generateelectricity.In fact, modern industrial civilization depends on petroleum and itsproducts; the physical structure and way of life of the suburbancommunities that surround the great cities are the result of an ample andinexpensive supply of petroleum. In addition, the goals of developingcountries to exploit their natural resources and to supply foodstuffs for theunderdeveloped populations, are based on the assumption of petroleumavailability. In recent years, however, the worldwide availability ofpetroleum has steadily declined and its relative cost has increased.Petroleum will probably no longer be a common commercial material bythe mid-21st century. Characteristics The chemical composition of all petroleum is principally hydrocarbons.Petroleum contains gaseous, liquid, and solid elements. The consistency ofpetroleum varies from liquid as thin as gasoline to liquid so thick that it willbarely pour. Formation Petroleum is formed under the earth s surface by the decomposition ofmarine organisms. The remains of tiny organisms that live in the sea and,to a lesser extent, those of land organisms that are carried down to thesea in rivers and of plants that grow on the ocean bottoms, are mixed withthe fine sands and silts that settle to the bottom in quiet sea basins. Suchdeposits, which are rich in organic materials, become the source rocks forthe making of crude oil. The process began many millions of years agowith the development of abundant life, and it continues to this day. Thesediments grow thicker and sink into the seafloor under their own weight.As additional deposits pile up, the pressure on the ones below increasesseveral thousand times, and the temperature rises by several hundreddegrees. The mud and sand harden into shale and sandstone; carbonateprecipitates and skeletal shells harden into limestone; and the remains ofthe dead organisms are transformed into crude oil and natural gas.Once the petroleum forms, it flows upward in the earth s crust because ithas a low density. The crude oil and natural gas rise into the microscopicpores of the coarser sediments lying above. Frequently, the rising materialencounters a dense layer of rock that prevents further movement. In otherwords, the oil has become trapped, and a reservoir of petroleum is formed.A significant amount of the upward-migrating oil, however, does notencounter impermeable rock but instead flows out at the surface of theearth or onto the ocean floor. Historical Development These surface deposits of crude oil have been known to humans forthousands of years. In the areas where they occurred, they were longused for such limited purposes as caulking boats, waterproofing cloth andfueling torches. By the time of the Renaissance, some surface depositswere being distilled to obtain lubricants and medicinal products, but thereal exploitation of crude oil did not begin until the 19th century. TheIndustrial Revolution had by then brought about a search for new fuels,and the social changes it effected had produced a need for good, cheapoil for lamps. People wished to be able to work and read after dark. The search for a better lamp fuel led to a great demand for rock oil ,thatis, crude oil, and various scientists in the mid-19th century weredeveloping processes to make commercial use of it. Thus the quest for greater supplies of crude oil began. For several yearspeople had known that wells drilled for water and salt occasionallycontained petroleum, so the concept of drilling for crude oil itself soonfollowed. The first such wells were dug in Germany in 1857-59, but theevent that gained world fame was the drilling of an oil well near Oil Creek,Pennsylvania, by Colonel Edwin L. Drake in 1859. Exploration In order to find crude oil underground, geologists must search for asedimentary basin in which shales rich in organic material have beenburied for a sufficiently long time for petroleum to have formed. Thepetroleum must also have had an opportunity to migrate into porous trapsthat are capable of holding large amounts of fluid. The occurrence ofcrude oil in the earth s crust is limited both by these conditions, whichmust be met simultaneously, and by the time span of tens of millions to ahundred million years required for the oil s formation. Petroleumgeologists and geophysicists, however, have many tools at their disposalto assist in identifying potential areas for drilling. Thus, surface mappingof sedimentary beds makes possible the interpretation of subsurfacefeatures, which can then be supplemented with information obtained bydrilling into the crust and retrieving samples of the rock layersencountered. In addition, increasingly sophisticated scientific techniques,having to do with the reflection and refraction of sound waves propagatedthrough the earth, reveal details of the structure and interrelationship ofvarious layers in the subsurf