Read the text and translate it into Russian.

Petroleum Origin

The general term “petroleum” includes both crude oil and natural gas. Crude oil nearly always has more or less natural gas associated with it, but in some places considerable quantities of gas may exist alone.

 Petroleum geologists have written more on the origin of petroleum than on any other subject. Speculation in this field was initiated in the 1860-s, but the problem of oil origin is still with us. Even extraordinary theories on the origin of hydrocarbons have surfaced over years. Some geologists believe petroleum to be of inorganic origin.

But most geoscientists consider petroleum to result from the breakdown of organic matter (plants and animals). Most geologists today agree that oil formed over million of years from the remains of tiny aquatic plants and animals that were exposed to the combined effects of time and temperature. In other words, oil formed from organic matter that was either " cooked" deep within the earth for long periods of time at low temperatures, or " cooked" for short periods of time at high temperatures.

Most crude oils formed from one-celled plants and animals, which floated on the surfaces of ancient oceans. As these organisms died, they settled to the ocean floor and were covered with mud. If the mud did not contain enough oxygen for the soft parts of these organisms to decay, with sufficient time and temperature, and over probably millions of years, the organic materials were slowly converted to oil.

Crude oils are mixtures of many different compounds. Most of the compounds found in oil are composed of hydrogen and carbon. In addition to these materials, called hydrocarbons, other compounds containing small amounts of sulphur, oxygen and nitrogen are also present.

Oil is a black viscous product of composition:

carbon	80% to 89%
hydrogen	12% to 14%
nitrogen	0, 3% to 1%
sulphur	0, 3% to 3%
oxygen	2% to 3%

The chemical composition itself, the kinds of rocks with which petroleum is associated, and certain optical tests, all point to the organic origin of petroleum.

Petroleum is not necessarily found where it was generated, but instead may have migrated from its source rock over large distance. Temperature changes, earth movements and differences in density between oil and salt water, caused the oil to migrate from the source rock, to accumulate in favourable geological formations. Under the pressure differential petroleum moves outward and upward along zones of increased permeability to a reservoir rock and accumulates there. Although the term “oil pool” is commonly used, there is really no actual pool or underground lake, but rather there is a porous rock saturated with oil and covered with an impermeable layer.

 

 

Therefore, several geologic elements are necessary for oil and gas to accumulate in sufficient quantities to create a pool large enough to be worth producing. These elements include an organic-rich source rock to generate the oil or gas, a porous reservoir rock to store the oil and gas in, and some sort of trap to prevent the oil and gas from leaking away.

 

Find in the text and read out English equivalents of these words and word-combinations.

Неочищенная нефть; попутный газ; происхождение нефти; образоваться из органических веществ; распад органического вещества; преобразоваться в нефть; смесь углеводородов; темная вязкая жидкость; различные химические соединения; состоять из углерода, водорода и кислорода; перемещаться из материнской породы; перепады давления; изменения температуры; разница в плотности между нефтью и соленой водой; накапливаться в породе – коллекторе; пористая порода, насыщенная нефтью; залежь нефти; непроницаемый пласт; накапливаться в достаточном количестве.

 

⇐ Предыдущая12345678Следующая ⇒

Поделиться: