June, 2005 • MarineNews 13
Circle 235 on Reader Service Card
NEWS
By Larry Pearson
There has been an interesting conver-
gence of technology and market opportu-
nity that is shaping the design of supply
vessels serving the offshore drill rigs and
platforms in the Gulf of Mexico (GOM).
Both of these forces spotlight the need for
supply vessels to carry more liquid mud.
Liquid mud is essential in drilling bore
holes in the earth. It is a liquid with con-
siderable suspended solids and the liquids
can be either oil or water based.
Drilling operations need so much more
mud for basically two reasons: The
increased drilling of wells in deepwater
and the incentives offered by the Minerals
Management Service (MMS) to drill very
deep wells (over 15,000 feet) in shallow
water fields that already had their hydro-
carbons extracted at lesser depths.
Faced with the demand for as much as
100,000 barrels of liquid mud per "spud-
ded" well, the offshore vessel operators
have been literally working overtime to
develop a vessel capable of holding mas-
sive amounts of liquid mud at a reason-
able cost.
Hornbeck Offshore Services has devel-
oped a plan for a high capacity mud ves-
sel far exceeding what is currently avail-
able. Their answer is to take a pair of
existing sulfur tankers and convert them
to haul at least twice as much mud as can
be carried on any vessel serving the GOM
at the present time.
Not only will these vessels haul large
amount of mud they can support ROV
operations as well as construction and
other subsea tasks. Cost is expected to be
$55-60 million per vessel.
In 2001, Hornbeck purchased the Ener-
gy Service 9001 from Freeport-
McMoRan Sulphur. Recently they pur-
chased a sister ship Benno C. Schmidt
from a private owner.
Both vessels are 395 ft. by 72 ft. with a
25-ft. deep hull. The sulfur tankers make
attractive conversion candidates since the
specific gravity of the sulfur product they
carried is similar to that of liquid mud.
Sulfur is mined on the top of salt domes in
GOM.
The tankers look radically different
than typical supply boats. They definitely
look like a bulk product tanker with a tall
aft mounted superstructure much like a
small oil tanker.
Both the Energy Service 9001 and the
Benno C. Schmidt hauled molten sulfur
from undersea deposits at Main Pass in
the GOM to Port Sulfur, La. Freeport
closed their sulfur mining operations and
their terminals in 2002.
According to Hornbeck company Presi-
dent Todd Hornbeck, "We believe the
HOS 370 Multi Purpose Supply Vessels
(MPSVs) will be the largest offshore sup-
ply vessels in the world, each with cargo
carrying capacities over 10,000 tons with
a minimum of 30,000 barrels of liquid
mud." The vessels would certainly be the
largest in the GOM and probably the
world with a 30,000 barrel liquid mud
capacity. The largest carriers of liquid
mud at the present time working in the
GOM are the Edison Chouest Offshore
280-ft. series of vessels with a liquid mud
carrying capacity of 15,644 barrels and a
deadweight tonnage of 4,811.
In the current Hornbeck fleet, their 265-
ft. class of supply boats have about 30
percent of the deadweight and mud carry-
ing capacity of the sulfur tankers.
Hornbeck has spent about three years to
develop a plan to develop a more versatile
DP-2 vessel that could serve through the
life cycle of deepwater wells including
exploration, development and production
of an offshore field.
During this planning period it became
obvious that to carry 30,000 barrels of liq-
uid mud the vessel would have to be
designed much more like a tanker and less
like a conventional supply boat. But
building such a ship would be cost pro-
hibitive, so converting an existing tanker
seemed the best bet.
Not just any tanker would do. It had to
Sulfur Tankers to be Converted to Supply Vessels
The sulfur tanker Benno C. Schmidt at her dock in Port Sulfur, La.
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