fide content reaches respectively 130 ppm and 60 ppm in the produc-
tion and gas-lift risers. The impact is very stringent specifications
and designs for the pipe materials and welds, which include:
• Effective Fatigue Design factor of 100 ( 10 is standard but due
to the potential souring from the reservoir, an additional Knock-
Down Factor of 10 has been added). For a design life of 25
years, the acceptable fatigue life is 2,500 years.
• All riser welds in contact with fluid and gas are characterized
as severe sour service and are subjected to extensive sulfide
stress corrosion cracking qualification testing for 720 hours, in
line with NACE standard requirements.
• Full-scale laboratory testing of all weld types in the production
(riser and flowline) system.
There is also potential for sand production during field life. With
continuous sand production from the reservoir estimated at a maxi-
mum of 20 ppm and a sand particle maximum size of 140 microns
– combined with injected lift gas and produced gas in the production
riser – there is the risk of erosion at the top of the risers. However,
this is mitigated by the fact that:
• The production risers top assemblies are made of duplex stain-
• The flexible jumpers and their extremities are made respec-
tively of stainless steel and CRA-clad carbon steel.
Kaombo is Total’s fifth deep offshore development in Angola and
its first in block 32. Its two FPSOs will also bring the total number
operated by Total off Angola to six, following the single facilities installed for the Girassol, Dalia, Pazflor, and CLOV projects on block 17.
The company and partners Sonangol P&P, Sonangol Sinopec In-
ternational, ExxonMobil, and Galp Energia opted for two FPSOs to
develop six fields in an 800-sq km (309-sq mi) area in the central and
southeastern part of block 32. “It is perhaps our largest project area-
wise,” Afolabi said, “and it is the first time that Total has chosen to con-
vert two VLCCs as opposed to commissioning a newbuild floater. This
was done primarily for reasons of costs and scheduling efficiency.”
Saipem has an EPCI contract to convert the two tankers, with the
contractor’s Floaters Business Unit west of Paris managing the pro-
gram. Each vessel will have oil treatment capacity of 115,000 b/d;
water injection capacity of 200,000 b/d; gas compression of 100
MMcf/d; and oil storage of up to 1. 8 MMbbl.
“It’s a D1B2 – design one, build two – conversion,” said a Total Ka-
ombo project spokesperson, “so both FPSOs are almost twins. We say
‘almost’ since marginal adjustments are unavoidable to cater for the
different production loops they are connected to. Some minor adjust-
ments might also be made to Kaombo Sul, the second floater to be
deployed, following lessons learned from the first one, Kaombo Norte.
The six fields are Gengibre, Gindungo, and Caril, to be produced
via Kaombo Norte, and Louro, Mostarda, and Canela for Kaombo
Sul. The FPSOs will both be moored in 1,650 m ( 5,413 ft) of water,
nearly 20 km ( 12. 4 mi) apart. There will be an eight-month interval between first oil from Kaombo Norte and Kaombo Sul. Start-up,
ramp-up, and plateau of field production will follow a very specific,
already-defined strategy, and different production loops will come
onstream in various stages.
Saipem is performing most of the topsides fabrication at its Kari-mun Island yard in Indonesia, although the Petromar yard in Am-briz, Angola, is constructing two topsides modules for Kaombo Sul:
the 700-metric ton (771-ton) S5 subsea methanol injection and dead
oil system and the 882-metric ton (972-ton) S2 with chemical injection and fiscal metering systems.
Integration of the Indonesian-built topsides onto the converted
FPSO hulls should start this summer at the Sembawang shipyard
in Singapore. Following its subsequent voyage to Angola, Kaombo
Sul will stop off at the Paenal yard for integration of the two “made
in Angola” modules.
During 4Q, the Technip/Heerema Marine Contractors joint venture should start installation of Kaombo’s subsea umbilicals, risers
and flowlines network which will be the most extensive to date in
the Gulf of Guinea and one of the largest in the world. This will feature 300 km (186 mi) of rigid and flexible production and injection
pipelines, with Angoflex’s spoolbase in Barra do Dande, Angola, fab-
Left: Fabrication of FPSO piles at SNCL Yard, Port Harcourt. Right: The completed Egina FPSO hull berthed at the quayside in South Korea.
Reserves from Kaombo’s six fields will be produced through two FPSOs,
which will be moored in 1,650 m ( 5,413 ft) of water.