block 393 that was drilled at a water depth of
2,269 m ( 7,446 ft), to a total depth of 8,042 m
( 26,385 ft). The discovery well encountered
more than 152 m (500 ft) of net oil pay.
The two fields are together estimated to
hold recoverable reserves amounting to 650
The reservoirs of the Appomattox and
Vicksburg fields are located in the Norphlet
play, a geological formation that extends from
onshore to the deep waters, characterized by
high pressures and well temperatures.
Rydberg, the third major discovery in the
area, was made in July 2014. The field is located within the Mississippi Canyon block 525.
The Gettysburg prospect in the Desoto Canyon block 398 is also being explored. These
two prospects are located approximately 16
km ( 10 mi) from the Appomattox field.
The Gettysburg and Rydberg prospects
are currently being reviewed for a possible
connection to the Appomattox infrastructure,
which will further increase the total estimated
discovered resources in the area to more than
A key part of Shell’s ability to
reduce costs on the Appomattox
project has been its ability to standardize equipment and reduce its
drilling costs. A key cost-saving
feature was the elimination of a
platform rig, which has enabled
Shell to realize considerable space
and weight savings on the host facility. Production will take place at
the subsea drill centers and wells.
“Putting a platform rig on the host facility
becomes almost too challenging,” said Rick
Tallant, Asset Manager–Gulf of Mexico East.
“The weight and space that you need to do that
becomes difficult. The strategy there is to produce ever ything back from a subsea into a single
host, and to do that as efficiently as possible.”
Shell has also been able to reduce some of its
subsea costs as well, particularly in its export
systems. “In many ways, we’ve had to revamp
a few things, but we’ve made unexpected prog-
ress on reducing costs on Appomattox, even
during project execution,” Tallant said.
In some cases, design engineers removed
or reduced redundant systems, while at the
same time improving Shell’s ability to run
equipment for longer without failure. This, in
turn, has enabled Shell to lower break-even
prices on the project.
“We have spent a lot of time over the past
couple of years rescoping our projects and
understanding the best and most efficient way
of producing these fields,” Tallant said. “We
also looked at ways in which we could shorten
cycle times to be able to get the returns and
the cash flow faster.”
Shell worked with its vendors and contrac-
tors to find ways of making its engineering
and design concepts more efficient, and to
look for new ways of reducing project costs.
Reducing drilling and completion costs has
been a key focus area. In the wake of Macondo,
Shell took a fresh look at its drilling programs,
both in terms of safety and efficiency. The lean
approach has paid dividends with the advent of
the market downturn. The search for drilling
efficiencies led Shell to adopt a standardized
well design. In the past, Tallant notes, each
individual well might have had a bespoke design.
The result has been significant operational ef-
ficiencies, greater savings, and less downtime.
“Honestly, it makes things run much faster,”
Tallant observed. “We find that if you standard-
ize the well and all its various components, the
crew knows exactly how to drill and complete
each well. They’ve done it before with the same
type of well they’ve done previously.”
Shell has awarded several contracts in sup-
port of field development since the project was
sanctioned in 2015. Some of the more notable
contracts are described below.
• Oceaneering International, Inc. is providing services and products to support
the design, fabrication, and installation of
ancillary flowline hardware. Oceaneering
is also supplying 60 km ( 37 mi) of electro-
hydraulic steel tube control umbilicals
for the project.
• Dresser-Rand delivered power generation
equipment for a combined cycle power
plant (CCPP) for the Appomattox plat-
form. The ~150 MW CCPP will feature
four 27 M W gas turbine-driven generator
sets equipped with heat recovery systems
and a 40 MW steam turbine generator.
• First Subsea is supplying subsea
mooring line connectors for the
• Danos fabricated three board-
ing valve skids and one service
line skid, each weighing in at
approximately 160 tons.
• Materia Inc., in conjunction
with Aegion Corp., will supply
an insulation system to provide
a thermal barrier between flow-
lines and seawater.
• Delmar performed mooring de-
sign engineering services for
the floating platform, which included global mooring analysis
verification using its mooring
analysis software. •
Structural re-engineering and
“competitive rescoping” are
enabling Shell to continue to
advance its deepwater program
in the deepwater Gulf of Mexico.
The hull of Shell’s Appomattox production platform arrived at Ingleside, Texas, in October 2017
aboard the M/V Xin Guang Ha. (Courtesy COSCO Shipping Heavy Transport)