Geographic and Stratigraphic distribution of petroleum

The petroleum deposits of the world are located in sedimentary basins and in geosynclines. The most important petroleum resources of the world are located in the environs of land-locked seas occupying inter-continental troughs or depressions in the earth's crust. The principal regions of this character are:

1. The environs of the Mediterranean, Red, Black, and Caspian seas and the Persian Gulf, occupying the depressed segment between the continents of Africa, Europe, and Asia. In this region, the prolific oil fields of the U.S.S.R. and the Near and Middle East are located.

2. The environs of the Gulf of Mexico and the Caribbean Sea, lying in the landlocked basin between the continents of North and South America. This region contains the most important petroleum resources so far developed in the Western Hemisphere: Trinidad, Venezuela, Columbia, Mexico, and the Gulf Coast area in the United States.

3. The environs of the shallow island-studded seas which lie between the continents of Asia and Australia in the Far East. Important petroleum resources have already been developed on the islands of Borneo, Sumatra, Java, and New Guinea, and much promising territory remains to be explored in this region.

4. The environs of the land-locked Arctic Sea, lying in the north-polar depression between the continents of North America, Europe, and Asia. This region is almost wholly unexplored, but it is characterized throughout by conspicuous surface evidences of petroleum.

Many important oil and gas fields of the world are located in smaller geo-synclines and sedimentary basins. In North America there are important petroleum resources in the Appalachian geosyncline, Michigan basin, Eastern Interior coal basin, the West Texas basin, the Rocky Mountain geosyncline, and the Pacific geosyncline. In South America the petroleum resources of Argentina are situated in local sedimentary basins and in geosynclines. In the U.S.S.R. the important oil and gas deposits of the Ural-Volga and Kama fields are located in a large interior sedimentary basin.

The supply of oil and natural gas in the world is distributed in rocks ranging in age from pre-Cambrian to Quaternary.

The younger geological periods are more productive of oil than the older ones. More than one-half of the world's oil production has come from rocks of the Tertiary period. The Cretaceous period is next in importance in total oil production. More than 16 per cent of the total world production has come from Cretaceous rocks. The Pennsylvanian period is third in importance In the amount of oil produced.

Unit 2

I Learn the words:

1. chemical - химический

2. complex - сложный

3. mixture - смесь

4. liquid - жидкий, жидкость

5. solid - твердый, твердое тело

6. hydrocarbon - углеводород

7. compound - соединение

8. oxygen - кислород

9. nitrogen - азот

10. sulphur - сера

11. amount - количество, величина

12. matter – материя, вещество

13. impurity - примесь

14. substance - вещество

15. to occur - происходить, встречаться

16. crude oil - сырая (неочищенная) нефть

17. pressure - давление

18. to dissolve - растворять

19. volatile - летучий

20. colour - цвет

21. odour - запах

22. specific gravity - удельный вес

23. viscosity - вязкость

24. boiling - point - точка кипения

25. fluorescence - свечение, флюоресценция

26. resistance - сопротивление

27. motion - движение

movement - движение

25. reason - причина

25. means - средство, способ