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1. Refined crude oil is a commodity with very few uses.

2. A company is integrated if it includes upstream or downstream activities.

3. Failure to manage rising oil pressure resulted from gushers.

4. The running down reservoir pressure is regulated by injecting gas into the well.

5. Thermal distillation is a process where crude oil is separated into its constituent parts by condensing out its components at different temperatures.

6. Higher-value products are obtained by thermal distillation.

7. Pure streams are the components of crude oil that can be sold separately.

8. In Europe oil is measured in kilolitres.

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CRUDE OIL, ITS FORMS AND CLASSIFICATIONS

Crude oil – as petroleum directly out of the ground is called – is a remarkably varied substance, both in its use and composition. It is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds. There is an infinite number of hydrocarbons; they are all distinguished by their internal structure, carbon-hydrogen proportion and, therefore, by their chemical and physical properties.

Hydrocarbons are compounds of hydrogen (11-14 %) and carbon (84-86 %) that, at normal temperatures and pressure, may be gaseous, liquid or solid according to the complexity of their molecules. The natural deposits are liquid deposits called crude oil, the gaseous ones known as “natural gas” and the solid ones – “bitumen”, “asphalt” or “wax”depending on the relative proportion of the various hydrocarbons present in the mixture.

The hydrocarbons present in crude petroleum are classified into three general types: paraffins (alkanes), naphthenes (cycloalkanes), and aromatics (arenes). In addition, there are other types, olefins (alkenes) and diolefines (dienes) and acetylenes (alkynes) that are formed during processing by the cracking or dehydrogenation of paraffins and naphthenes. Crude oils tend to be a mixture of paraffins-naphthenes-aromatics, with paraffins and naphthenes the predominant species. Oil also has small quantities of organic substances containing sulphur – hydrosulphuric compounds, oxygen – asphaltic and tarry compounds, as well as nitrogen and trace amounts of metals such as iron, nickel, copper and vanadium.

Oil is found in geologic formations beneath the Earth’s surface and is recovered through drilling and operating oil wells.An oil well produces predominantly crude oil, with some natural gas dissolved in it. Because the pressure is lower at the surface than underground, some of the gas will come out of solution and be recovered (or burned) as associated gas. A gas well produces predominantly natural gas. However, because the underground temperature and pressure are higher than at the surface, the gas may contain heavier hydrocarbons in the gaseous state. At surface conditions these will condense out of the gas to form natural gas condensate, often shortened to condensate. Condensate resembles petrol in appearance and is similar in composition to some volatile light crude oils.

Crude oil may also be found in semi-solid form, mixed with sand and water. This form of crude oil is also called crude bitumen. Bitumen is a sticky, viscous, black, tar-like form of crude oil that is so thick and heavy that it must be heated or diluted before it willflow.

Crude oil can vary greatly in appearance. It is usually black or dark brown, although it may be yellowish, reddish, or even greenish. It can be a straw-coloured liquid or tar-black solid. Red, green and brown hues are not uncommon.

The petroleum industry generally classifies crude oil by the geographic location it is produced in (e.g. West Texas Intermediate, Brent, or Oman), its API gravity (an oil industry measure of relative density (specific gravity) based on a scale of degrees API), and its sulphur content. Crude oil may be considered light if it has low density or heavy if it has high density; and it may be referred to as sweet if it contains relatively little sulfur or sour if it contains substantial amounts of sulphur.

Crude oil is refined by relying on the differing boiling points of the various hydrocarbons within crude oil – 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 – 1-110 degrees Celsius (55 to 400 degrees Fahrenheit). Those used for jet fuel boil in the range of 150-205 °C (300 to 550 °F), and those for diesel, at about 260-315 °C (700 °F).

6. Письменно о тветьте на вопросы по тексту .

1. What is crude oil?

2. What physical forms of natural deposits do you know?

3. How are chemical forms of crude oil distinguished?

4. What is the difference between associated gas and gas condensate?

5. Why is bitumen referred to as a semi-solid form of crude oil?

6. What other classifications of crude oil exist?

7. Why is crude oil boiling point an important factor?