4.2. Read and translate the text using a dictionary:

What is Oil?

All over the world, at various depths beneath land and sea, there are accumulations of hydrocarbons formed long ago by decomposition of animal and vegetable remains. 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. 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.

The oil of most oil fields consists of methane and saturated hydrocarbons. The molecules of methane hydrocarbons are a chain of series-connected atoms of carbon with atoms of hydrogen added. Their structure is determined by the formula CnH2n+2, where n shows the number of atoms in a molecule beginning with one.

Hydrocarbons with a small number of carbon atoms from CH4 to C4H10 are gases under standard conditions (a pressure of 760 mm of mercury and a temperature of +20 degrees Centigrade). Heavier hydrocarbons, from C5H12 to C16H34, are liquids under these conditions. Methane hydrocarbons with a still greater content are solids called paraffines and ceresines.

Oil also has a small quantities of organic substances containing sulphur – hydrosulphuric compounds, oxygen – asphaltic and tarry compounds and nitrogen.

In its widest sense “petroleum” embraces all hydrocarbons occurring naturally in the earth. In its narrower, commercial sense, “petroleum” is usually restricted to the liquid deposits – crude oil, the gaseous ones being known as “natural gas” and the solid ones as “bitumen”, “asphalt” or “wax” according to their composition.

Most crude oils, although liquid as such, contain gaseous and solid hydrocarbons in solution. The gases come out of solution either on the release of pressure as the crude oil is or during the first stages of refining, and contribute to the total gas production. Some of the solids are recovered during refining as bitumen and wax, some stay in solution in the liquid oil products. Natural gas is also found associated with crude oil as a gas cap above the oil or on its own, unassociated with oil.

Petroleum is a substance with a characteristic smell. The odour of petroleum depends on the nature, composition and quantity of hydrocarbons and different impurities. Its colour varies from light brown to dark brown, nearly black. Specific gravity of oil determines its colour. The heavier the oil the darker is the colour. Oil is much lighter than water. It doesn’t dissolve in water and forms a thin rainbow film on its surface. All sorts of oil are combustible.

4.3. Answer the questions on the text:

1.What are hydrocarbons? 2. How were they formed? 3. How are hydrocarbons distinguished? 4. What formula determines the structure of methane hydrocarbons? 5. What do we usually mean by the word “petroleum”? 6. Do most oils contain gaseous or solid hydrocarbons in solution? 7. When do gases come out of solution? 8. What happens during the first stages of refining? 9. What is called a gas cap? 10. What does the odour of petroleum depend on? 11. What determines its colour? 12. What is the dependence of the colour of oil on its specific gravity? 13. Is water lighter or heavier than oil? 14. Are all sorts of oil combustible?

4.4. Give the English equivalents to the following word combinations from the text:

во всем мире, разложение животных остатков, при обычной температуре, в

зависимости от сложности, соответственно, как таковые, в самом широком смысле, в более узком смысле слова, во время добычи сырой нефти, способствуют, оставаться в растворе, попутно с сырой нефтью, сам по себе, чем тяжелее.

4.5. Match the words in the left column (A) with their equivalents on the right (B):

A B

1) stage 2) various 3) beneath 1) limit 2) ordinarily 3) discover

4) normal 5) liquid 6) sense 4) part 5) produce 6) different

7) proportion 8) embrace 9) restrict 7) over 8) decrease 9) meaning

10) above 11) find 12) manufacture 10) fluid 11) cover 12) below

13) usually 14) release 13) step 14) common

4.6. Match the words in the left column (A) with their opposites on the right (B):

A B

1) various 2) wide 3) complexity 1) artificially 2) absent 3) light

4) most 5) present 6) naturally 4) external 5) finite 6) last

7) first 8) internal 9) heavy 7) narrow 8) least 9) decompo-

10) infinite 11) composition sition 10) simplicity 11)the same

4.7. State whether the sentences are true (T) or false (F):

1. Hydrocarbons formed long ago by composition of an animal and vegetable remains at a definite depth beneath land and sea.

2. Hydrocarbons never occur naturally in the earth.

3. Most crude oils contain gaseous and solid hydrocarbons.

4. Bitumen and wax form separate deposits.

5. Natural gas forms separate deposits or is associated with crude oil.

6. The colour of petroleum determined by its specific gravity varies.

4.8. Complete the sentences in column A choosing the proper ending from column B:

A B

1) Hydrocarbons are compounds of …. 1) solution

2) Most crude oils contain … 2) water

3) Some of the solids are recovered during… 3) crude oil

4) The gases come out of …. 4) gaseous and solid hyd-

5) Gas cap is formed above … rocarbons in solution

6) Petroleum doesn’t dissolve in… 5) hydrogen and carbon

6) refining

4.9.Retell the text using the following word combinations as a plan:

Accumulation of hydrocarbons, various composition, infinite number, natural deposits, to consist of, small quantities, to contain in solution, to recover during refining, to find associated with crude oil, the odour of oil, the colour of oil, lighter than, combustible.

UNIT 5 ORIGIN, MIGRATION AND ACCUMULATION OF OIL

5.1. Remember the meaning of the following words:

1. origin - происхождение 2.. migration – движение нефти через породы 3. accumulation – залежь, скопление 4. exist - существовать 5. decomposition – разрушение 6. marine - морской 7. mud - грязь 8. silt - ил 9. constituent – составная часть 10. derive from – происходить от 11. shallow - мелкий 12. settle - осаждаться 13. decay -разложение 14. content - содержание 15. source beds – нефтематеринская порода 16. transform – преобразовывать 17. overburden – наносы, покров 18. associated water – попутная вода (добываемая вместе с нефтью) 19. squeeze out - выдавливать 20. adjoining – смежный 21. layer = bed = formation – пласт, слой 22. permeable - проницаемый 23. pore - пора 24. fracture = crack – разлом, трещина 25. evidence – признак, доказательство 26. evaporate – испаряться, 27. subsoil – подземный 28. impervious - непроницаемый 29. trap – улавливать (о жидкости); ловушка 30. capacity – вместимость 31. interstices - пустоты 32. reservoir rock – коллекторская порода 33. seal = cap rock – покрывающая порода 34. seep - просачиваться