A Mineral Store/rome
107
continental shelves in various parts of the world in the search for
natural gas and oil. In the Gulf of Mexico, the Bass Strait between
Tasmania and Australia, the Mediterranean, the Gulf of Suez, the
Sea of japan, the Black Sea, the North Sea, the Sulu Sea in the
Philippines, the search continues with drilling bits gnawing into
promising structures found in surveys. And as the search widens,
moving into the deeper waters, the risk to men and equipment
grows. Violent storms arise suddenly in the Arabian Gulf, ice oes
create problems off Alaska and hurricane wreak havoc in the Gulf
of Mexico. Like any other push into new territory, this expansion
of the oil industry into the sea is taking its tell of men and equip—
ment. One wintry day the rig Sea Gem, the rst to nd natural gas
in the North Sea, foundered with the loss of half its crew. Fortun—
ately alongside such disasters come improvements in rigs, equip—
ment and techniques to make the job safer and easier. And the goal
of this effort? Geologists estimate that the continental shelf holds
supplies of oil at least equal to those on the land—some
r,ooo,ooo,ooo,ooo barrels!
Although their origin is still disputed, most geologists believe
that oil and natural gas are formed from animals and plants which
ourished in the warm seas millions of years ago. Remains of these
marine organisms together with sand, silt and other debris formed a
thick cover over the sea oor. As time went by more sediments
collected, layer upon layer, compressing the material lying under
them. With the great pressure and temperature involved, the dead
creatures were crushed together, and without the oxygen needed to
bring about complete decay their cell matter was slowly converted
into hydrocarbons. This chemical conversion was also helped by
various minerals which had collected with the dead organisms and
which acted as catalysts to speed up the process.
If the overlying
rocks formed an impenetrable' barrier and if sideways movement
was
also prevented, the hydrocarbons remained, together with
water, in the pores of the rock in which they were formed. The oil
and gas traps sought by the petroleum geologists are often nothing
more than the crests of folds in oil—bearing rock which have been
‘Capped’ by an impermeable rock. The gas or oil originally dispersed
throughout the rocks has migrated upwards to occupy the top of the
fold while the water lls the remainder of the reservoir. Another
_
kind of trap occurs when masses of rock salt have forced their way
upwards, distorting the hydrocarbon—enriched strata into arches
107
continental shelves in various parts of the world in the search for
natural gas and oil. In the Gulf of Mexico, the Bass Strait between
Tasmania and Australia, the Mediterranean, the Gulf of Suez, the
Sea of japan, the Black Sea, the North Sea, the Sulu Sea in the
Philippines, the search continues with drilling bits gnawing into
promising structures found in surveys. And as the search widens,
moving into the deeper waters, the risk to men and equipment
grows. Violent storms arise suddenly in the Arabian Gulf, ice oes
create problems off Alaska and hurricane wreak havoc in the Gulf
of Mexico. Like any other push into new territory, this expansion
of the oil industry into the sea is taking its tell of men and equip—
ment. One wintry day the rig Sea Gem, the rst to nd natural gas
in the North Sea, foundered with the loss of half its crew. Fortun—
ately alongside such disasters come improvements in rigs, equip—
ment and techniques to make the job safer and easier. And the goal
of this effort? Geologists estimate that the continental shelf holds
supplies of oil at least equal to those on the land—some
r,ooo,ooo,ooo,ooo barrels!
Although their origin is still disputed, most geologists believe
that oil and natural gas are formed from animals and plants which
ourished in the warm seas millions of years ago. Remains of these
marine organisms together with sand, silt and other debris formed a
thick cover over the sea oor. As time went by more sediments
collected, layer upon layer, compressing the material lying under
them. With the great pressure and temperature involved, the dead
creatures were crushed together, and without the oxygen needed to
bring about complete decay their cell matter was slowly converted
into hydrocarbons. This chemical conversion was also helped by
various minerals which had collected with the dead organisms and
which acted as catalysts to speed up the process.
If the overlying
rocks formed an impenetrable' barrier and if sideways movement
was
also prevented, the hydrocarbons remained, together with
water, in the pores of the rock in which they were formed. The oil
and gas traps sought by the petroleum geologists are often nothing
more than the crests of folds in oil—bearing rock which have been
‘Capped’ by an impermeable rock. The gas or oil originally dispersed
throughout the rocks has migrated upwards to occupy the top of the
fold while the water lls the remainder of the reservoir. Another
_
kind of trap occurs when masses of rock salt have forced their way
upwards, distorting the hydrocarbon—enriched strata into arches