Page 13 - 440

VI. Test Your Understanding of the Words:

In line 2 oil accumulations” means:

a) oil sheddings
b) oil agglomerations
c) oil scatterings
d) oil masses

VII. Word Choice.

Find the most suitable word to complete the following
sentence:
According to the last sentence of the passage the world’s
commercial sulphur comes from:

a) the German North Sea
b) industrial chemical plants
c) gas or oil before they are used as a fuel
d) formation water

Варіант 4.

Solid hydrocarbons are relatively rare, and are perhaps
best known from Pitch Lake in south-west Trinidad, where the
semi-solid bitumen is mined at the surface. There are other surface
occurrences, such as that of the Bermudez Pitch Lake in eastern
Venezuela. They also occur in bitumen dykes. Bitumen is also
valuable to the geologist in its elastico-viscous properties, for it
demonstrably flows yet can be broken by a hammer.
Varieties of solid bitumen include albertite, elaterate,
gilsonite, grahamite and wurtzillite. Kerogen is a solid bituminous
substance disseminated in sedimentary rocks, and in “oil shales”
and coals. It consists of about 80% carbon, with oxygen, hydrogen,
sulphur, and some nitrogen. It is pyrobitumen, yielding
hydrocarbons on heating (in the laboratory, to temperatures much
higher than those in petroleum reservoirs). Some varieties appear
to be primary source material for oil, others for gas; but kerogen
itself is the insoluble residue of diagenesis of organic matter, and