108
The Last Resource
and at the same time sealing them off with an impenetrable layer of
salt.
As long ago as 1896 au oil well was drilled off the coast of Cali—
fornia. By the 1930s drilling was being carried out in the lakes and
hays of Louisiana where in 1938 the rst off—shore oil was struck.
The rst drilling rigs used in the swamps and marshes were nothing
more than strong platforms mounted on wooden piles; everything—
the drilling equipment and the crew—was situated on them. Later,
the whole rig was mounted on a barge which could be towed to the
drilling location and then brought to rest on the shallow sea bottom.
But neither pile platforms nor barges were suitable for the deeper
locations which began to be explored after the Second World War,
and a new generation of drilling platforms which could be moved
from one place to another was evolved. Some of these steel islands
have long legs which can be lowered to lift the platform well above
the waves. Typical of such ‘jack—up’ rigs is the Neptune—Gascogne.
This rig can work in up
to 170 feet of water. Its hexagonal platform
is almost half au acre in area and stands on legs 3 50 feet tall. Another
type has legs incorporating ballast tanks which are ooded to bring
them to rest on the sea oor. The Kerr [145066 54 can sit on the
bottom in this way
at depths of water similar to those of the Neptune—
Gascogne.
As the search moved into still deeper waters, it became apparent
that systems which relied on the sea bottom for support would
_
eventually reach their economic or technical limit. The answer was
to develop oating rigs. At rst surplus naval vessels were converted
for drilling; the drill was lowered through a hole in the centre of the
vessel, or over the side. Although quite satisfactory—one of these
Heating rigs did the preliminary drilling for the ill—fated Mohole
project—the need for greater stability in rough seas led to the
semi—submersible oating unit. The platform of such a rig stands
well above the surface of the sea but its oat lies deep enough in it
to escape the forces of waves whipped up by storms. The full force
of the waves passes through the rig rather than against it and semi—
submersible rigs can operate in the roughest seas; one such rig,
Blue Water 2, has operated in twenty—ve—foot seas without excessive
pitching or rolling while another, Ocean Driller, rode out waves
fty feet high when Hurricane Hilda swept through the Gulf of
Mexico in 1964.
With the sea forever on the move, drilling rigs, even those that
The Last Resource
and at the same time sealing them off with an impenetrable layer of
salt.
As long ago as 1896 au oil well was drilled off the coast of Cali—
fornia. By the 1930s drilling was being carried out in the lakes and
hays of Louisiana where in 1938 the rst off—shore oil was struck.
The rst drilling rigs used in the swamps and marshes were nothing
more than strong platforms mounted on wooden piles; everything—
the drilling equipment and the crew—was situated on them. Later,
the whole rig was mounted on a barge which could be towed to the
drilling location and then brought to rest on the shallow sea bottom.
But neither pile platforms nor barges were suitable for the deeper
locations which began to be explored after the Second World War,
and a new generation of drilling platforms which could be moved
from one place to another was evolved. Some of these steel islands
have long legs which can be lowered to lift the platform well above
the waves. Typical of such ‘jack—up’ rigs is the Neptune—Gascogne.
This rig can work in up
to 170 feet of water. Its hexagonal platform
is almost half au acre in area and stands on legs 3 50 feet tall. Another
type has legs incorporating ballast tanks which are ooded to bring
them to rest on the sea oor. The Kerr [145066 54 can sit on the
bottom in this way
at depths of water similar to those of the Neptune—
Gascogne.
As the search moved into still deeper waters, it became apparent
that systems which relied on the sea bottom for support would
_
eventually reach their economic or technical limit. The answer was
to develop oating rigs. At rst surplus naval vessels were converted
for drilling; the drill was lowered through a hole in the centre of the
vessel, or over the side. Although quite satisfactory—one of these
Heating rigs did the preliminary drilling for the ill—fated Mohole
project—the need for greater stability in rough seas led to the
semi—submersible oating unit. The platform of such a rig stands
well above the surface of the sea but its oat lies deep enough in it
to escape the forces of waves whipped up by storms. The full force
of the waves passes through the rig rather than against it and semi—
submersible rigs can operate in the roughest seas; one such rig,
Blue Water 2, has operated in twenty—ve—foot seas without excessive
pitching or rolling while another, Ocean Driller, rode out waves
fty feet high when Hurricane Hilda swept through the Gulf of
Mexico in 1964.
With the sea forever on the move, drilling rigs, even those that