WHAT IS IT ?CRUDE OIL - as petroleum directly out of the ground is called - is a remarkably varied substance, both in its use and composition. It can be a straw-colored liquid or tar-black solid. Red, green and brown hues are not uncommon. Crude oil was formed by the action of bacteria, heat, and pressure on ancient plant and animal remains, and is usually found in layers of porous rock such as limestone or sandstone capped by an impervious layer of shale or clay that traps the oil (see reservoir). Crude oil varies in appearance and hydrocarbon composition depending on the locality where it occurs, some crudes being predominantly naphthenic, some paraffinic, and others asphaltic. Crude is refined to yield petroleum products.
The image of James Dean dripping with black oil from his Texas gusher in the 1956 movie "Giant" may have been compelling, but it's not descriptive of today's oil producers. For one thing, the days when a gusher signaled a big discovery are long gone. Since the 1930s, oil producers have used blowout preventers to stop gushers. In addition, not all crude oils behave in the Hollywood manner. Some flow about as well as cold peanut butter.
Until the late 19th century, an oil find often was met with disinterest or dismay. Pioneers who settled the American West dug wells to find water or brine, a source of salt; they were disappointed when they struck oil. Several historical factors changed that. The kerosene lamp, invented in 1854, ultimately created the first large-scale demand for petroleum. (Kerosene first was made from coal, but by the late 1880s most was derived from crude oil.) In 1859, at Titusville, Penn., Col. Edwin Drake drilled the first successful well through rock and produced crude oil. What some called "Drake's Folly" was the birth of the modern petroleum industry. He sold his "black gold" for $20 a barrel.
Petroleum was prized mostly for its yield of kerosene until the turn of the century. Gasoline was burned off, and bitumen and asphalt (the heavier parts of crude oil) were discarded. But gradually rising in importance were the incandescent light and the internal combustion engine. The former relied on oil-fired generating plants; the latter, on gasoline.
By the 1920s, crude oil as an energy source - not just as a curiosity - came into its own. But to many, it's still as mysterious as it was to ancient man. Even in the petroleum industry, most people never see crude oil.
Although various types of hydrocarbons - molecules made of hydrogen and carbon atoms - form the basis of all petroleum, they differ in their configurations. The carbon atoms may be linked in a ring or a chain, each with a full or partial complement of hydrogen atoms. Some hydrocarbons combine easily with other materials, and some resist such bonding.
The number of carbon atoms determines the oil's relative "weight" or density. Gases generally have one to four carbon atoms, while heavy oils and waxes may have 50, and asphalts, hundreds.
Hydrocarbons also differ in their boiling temperatures - a key fact for refiners who separate the different components of crude oil by weight and boiling point. Gases, the lightest hydrocarbons, boil below atmospheric temperature. Crude oil components used to make gasoline boil in the range of 55 to 400 degrees Fahrenheit. Those used for jet fuel boil in the range of 300 to 550 degrees, and those for diesel, at about 700 degrees.
The first refinery units to process raw crude oil are typically the crude and vacuum units. These units heat the crude oil to temperatures in excess of 700°F, vaporizing most of the oil. As the vapors rise in the tall towers that are part of these units, they cool and condense back into liquids at different temperatures based on the boiling points of the various products contained in raw crude oil. Within these towers are trays that collect the liquids and carry them off for further processing or for blending into finished products.
Crude oil is a surprisingly abundant commodity. The world has produced some 650 billion barrels of oil, but another trillion barrels of proved reserves have yet to be produced. An additional 10 trillion barrels of oil resources await development, assuming the price of oil someday justifies production. These resources include bitumen, shale oil and oil in existing fields that might be produced through enhanced recovery methods.
Talk of crude oil oozes with superlatives. Not only was crude oil the basis of the world's first trillion-dollar industry, it also is the largest item in the balance of payments and exchanges between nations. And it employs most of the world's commercial shipping tonnage.
HOW IS IT SHIPPED ?Crude Oil is shipped in tank cars AAR class III before 1927 which became ICC class 103, these were riveted steel Tank with dome until 1964. After 1964 they were fusion welded steel with dome, safety valve set at 35 psi, AAR class 103-W. These cars ranged from 8000-12500 gallons in size. See Tank Car Drawing for dimensions.
WHAT IS IT USED FOR ?The mysterious oil that sometimes seeped to the earth's surface had other uses as well. In Mesopotamia around 4000 B.C., bitumen - a tarry crude - was used as caulking for ships, a setting for jewels and mosaics, and an adhesive to secure weapon handles. Egyptians used it for embalming, and the walls of Babylon and the famed pyramids were held together with it. The Roman orator Cicero carried a crude-oil lamp. And, in North America, the Senecas and Iroquois used crude oil for body paint and for ceremonial fires. In more modern times crude oil is refined into many chemical products.WHAT A BARREL OF CRUDE OIL MAKES PRODUCT GALLONS PER BARREL GASOLINE 19.5 DISTILLATE FUEL OIL 9.2 (INCLUDES BOTH HOME HEATING OIL AND DIESEL FUEL) KEROSENE-TYPE JET FUEL 4.1 RESIDUAL FUEL OIL (HEAVY OILS USED AS FUELS IN INDUSTRY, MARINE TRANSPORTATION AND FOR ELECTRIC POWER GENERATION) 2.3 LIQUEFIED REFINERY GASSES 1.9 STILL GAS 1.9 COKE 1.8 ASPHALT AND ROAD OIL 1.3 PETROCHEMICAL FEEDSTOCKS 1.2 LUBRICANTS 0.5 KEROSENE 0.2 OTHER 0.3 TOTAL=44.2 GALLONS FIGURES ARE BASED ON 1995 AVERAGE YIELDS FOR U.S. REFINERIES. ONE BARREL CONTAINS 42 GALLONS OF CRUDE OIL. THE TOTAL VOLUME OF PRODUCTS MADE IS 2.2 GALLONS GREATER THAN THE ORIGINAL 42 GALLONS OF CRUDE OIL. THIS REPRESENTS "PROCESSING GAIN."
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© S.A. MCCALL