USES FOR NEW SHIPS
There are times when I really envy TV and film critics.
All they have to do is watch images flickering on a screen for a few hours and
then get out the pen to slaughter the work in an amusing way. And they have a
constant availability of material which means that they can forget about the
first part of the creative process - trying to think what to write about. This
thought came to mind as I was trawling through my work written over the past 20
years, as I do when faced with the need to be creative for the features section
of the website. I found the following article, written when I was a regular
columnist for Ship and Boat International and had the need to fill a couple of
pages and relate the works to photographs when nothing much was happening. The
article was written in 1998, but it seemed so apposite for today that I felt
that it was almost essential to publish it. So when you read it, remember that
it was written not in 2004 but in 1998.You might also think that Petrobras had
finally got themselves into a situation which could not get worse.
Back in the mid
1980s one could see stickers plastered on the walls of the pub lavatories and on
the back bumpers of ever other car in Aberdeen. "God give us another oil boom.
This time we promise we won't piss it away".
So, time will
tell whether the Scots are keeping their part of the bargain, but the new boom
is certainly offering opportunities for every major shipbuilder in the world,
and the majority of the hardware and the expertise required to take the industry
successfully into the 21st century appears to be marine.
The move further
offshore into deeper water has reduced the requirement for platforms, steel or
concrete jackets with accommodation, processing and drilling equipment on the
top, and increased the requirement for all sorts of floating objects.
In the North
Sea, the Far East and the South Atlantic numbers of floating production vessels
are in place and it seems inevitable that they will shortly be employed in the
Gulf of Mexico, although the Americans, stubbornly holding onto existing
technology, have installed the deepest jacket structures in the world using the
lifting capability of very large crane barges. This may be solely due to the
proximity of shallow water to deep water, but as drilling takes place further
and further away from the shelf attitudes may well change.
In the Campos
Basin the Brazilians are installing numbers of floating production units based
on semi-submersibles and anchored to the seabed by large diameter ropes, on the
basis that wires of any size will eventually break under their own weight if the
water is deep enough. Ropes on the other hand can be made neutrally buoyant. The
problem with rope is the diameter of the line and the consequent enormous size
of drum required to reel it out in the direction of the seabed. This requirement
has resulted in a number of newbuilding anchor handlers being fitted with extra
winches and dispatched to South America. The Brazilians are also at the
forefront of the use of high holding power anchoring systems such as the Vryhof
Stevmanta which change shape once tension is applied, and offer very high
holding capacity for a given deadweight. The downside of such systems is the
level of sophistication required to install them, however there is a steady
stream of imposing vessels leaving yards in Norway and coming to Aberdeen to be
fitted out before starting out on the long trip South – the latest the UT740
exploration the amazing ramforms are towing ever more complex arrays of guns and
cables and another vessel of the same design is to be found in McNulties yard on
the Tyne being fitted out as the first ramform FSPO.
The result of
the new injection of enthusiasm into the oil industry has been not unlike the
previous one at the beginning of the eighties, now almost too long ago to be
remembered by anyone but those whose memories may no longer be dependable. The
ship-owners are getting ahead of the operators and building the sort of ships
which they think the industry might want. The operators then make use of them.
one of the several entrepreneurial Norwegian ship-owners has built a number of
extremely large hulls potentially for use as platform ships. The Viking
Poseidon, for instance was recently seen in Aberdeen being fitted out by Subsea
as an ROV vessel, and is carrying out tie-in work west of the Shetlands.
Operated Vehicle) operations are yet another blossoming marine area. They used
to be used for little more than pipe-line inspections and their carriers were
usually converted trawlers with the ability to proceed slowing in the same
direction as the ROV itself.
Back with the
FSPOs, one of their features is the necessity to offload their oil into shuttle
tankers, and the connection and disconnection of these vessels is in itself a
specialised activity but in the main outside the remit of this article. However,
while the tanker operations are intended to be self sufficient there is a
tendency for tankers to snake back and forth in adverse weather. This tendency
may be combated either by means of a suitable azimuthing thruster in the bow or
else by using a tug to steady the stern.
As a consequence
larger and more elaborate standby vessels are being made available to the
operators. The latest – the Viking Provider is 69 meters long. The Grampian
Frontier operated by North Star to the west of the Shetlands has full anchor
handling capability as well as survivor accommodation for 300 people and 15 man
25 knot FRCs. As a consequence the edges are getting a bit blurred. Some of
these craft are also expected to undertake ROV work and so are fitted with
newbuildings illustrate the diversity of activities which are required of the
marine industry by the oil companies, and the enthusiasm with which builders and
owners have constructed and offered large sophisticated and powerful craft.
instance, DSDN offered the amazing Fennica and Nordica, initially as anchor
handling and towing vessels during the summer months, so that they could go back
to their primary purpose of being ice-breakers in the Baltic during the winter.
What might not have been immediately obvious to those marketing the craft, was
that ice-breaker sterns are not really compatible with anchor-handling and
towing. Additionally it has been found that vessels designed for the primary
purpose of breaking ice usually have a high fuel consumption, which reduces
their attraction as towing vessels.
Hence these two
ships, although unsuitable for their original purpose have found themselves
being pressed into service for other marine tasks, principally subsea work, and
so the Fennica is fitted with an A-frame of considerable dimensions and the
Nordica is fitted with an A-frame, a large crane and the other accessories which
are required for laying permanent moorings.
despite the limited success of the now middle aged well intervention vessels
constructed at the end of the last decade further large vessels capable of
carrying out subsea construction work are being built by Subsea and by Toisa,
and the industry in general, and the Norway in particular, is showing
considerable interest in the possibilities of coiled tubing work-overs from
monohulls. This task may be the ultimate test of the offshore support business.
Coiled tubing operations generally require an extremely stable platform and in
most cases a seal at the point of entry into the well which allows the pressures
to be contained.
As a result of
this, coiled tubing activities are not generally able to take place from
semi-submersibles, but are usually able to take place from platforms and
jack-ups, and often from jack-ups alongside platforms. Any monohull used for the
task should therefore be extremely stable, be capable of maintaining its
position above the wellhead, and be designed so that pitching rolling and heave
are minimised. This is a tall order, and it is generally felt that even if all
these requirements are fulfilled some further innovation in the actual operation
of the coiled tubing systems will also be required. One of the innovations being
promoted is a gyroscopically controlled platform, on which the reel will be
secured, and which will maintain position both vertically and laterally
independent of the ship.
So, going back
to the beginning of this article and the FPSO, a bewildering number of types of
craft have been briefly described, and the success or requirement for almost all
of them relates to the requirement for the industry to be able to drill and
recover hydrocarbons from deep water, particularly in the North Sea and the
marine activities which must be fulfilled if the operators are going to be
successful in their endeavours; initially extremely large and sophisticated
seismic vessels are required, light years away from the ex-trawlers which were
pressed into service in the 60s and 70s, then extremely large anchor-handlers
will be required in order to moor semi-submersibles in water depths of up to
6000 feet, and possibly in adverse weather conditions, then even larger vessels
will be required to install the subsea templates, flow lines and moorings for
the FPSO, and then the anchor-handlers will be needed again in order to connect
the FPSO, then the super standby vessels are required in order to provide
assistance for the tankers during connection and while connected, and then the
amazing work-over vessels are needed in order to avoid mooring the
semi-submersibles over the wells again.
It is no wonder
that the oil industry accountants see the whole think as something of a high
risk venture, and even small errors can multiply into major disasters. It is
rumoured that during a recent FPSO positioning, the winch on board was not
provided with quite enough capacity to accommodate the length of mooring wire
which had to be recovered. As a result the vessel and its attendant
anchor-handlers had to retire to sheltered waters so that modifications could be
carried out. The weather deteriorated, and it was some time before they could
all get back into the field and complete the job. The actual cost of this delay
in pounds sterling per day was so high that it made one realise the value of the
If all this
seems like too much work then one should look on the bright side and realise
that once one has drilled the hole, in general the stuff comes up to the surface
all of its own accord. It has the same sort of energy quotient as coal, and to
get coal out of the ground you have to send people down to do it.
On the downside
it might be worth quoting the words of the Petrobras Operations Director who
spoke at the Deep Water Mooring Conference in Aberdeen in 1996. "Remember" he
said "no situation is so bad that it can't get worse".
Vic Gibson 1998
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