Subsea Systems

Aug. 1, 2009

Gene Kliewer • Houston

Contract award tally

Subsea 7 Inc. has won a $150-million contract for offshore Angola pipeline engineering, construction, and installation. Engineering is to begin immediately with offshore work scheduled to begin in 2010 and run into 2011.

Subsea 7 also won an engineering, procurement, installation, and commissioning contract valued at $40 million fromBPNorway covering the Valhall Flank Gas Lift Pipelines and Wellhead Platform Riser Caisson project in the Norwegian North Sea. Work includes two 8-in. (20 cm) pipelines, one 6 km (3.7 mi) and one 7 km (4.35 mi), and a new caisson plus subsea tie-in spools at Valhall Flank South and Valhall Flank North platforms. Valhall is 290 km (180 mi) off the southwest coast of Norway in 70 m (230 ft) of water. The Valhall complex currently consists of seven platforms, five in the center and two flank installations.

BHP Billiton Pty Ltd. has awarded a SURF contract to Acergy S.A. for work offshore Western Australia. The project includes management, engineering, and offshore installation of subsea manifolds, flexible flowlines and risers, umbilicals, and tie-ins associated with an FPSO development. Work is scheduled to begin in the second half of this year with offshore installation by the ToisaProteus.

PLETs installed at Thunder Hawk

Helix Energy Solutions has installed two 86-ton PLETs (pipeline end terminals) at Murphy Oil Co.'s Thunder Hawk development in the Gulf of Mexico. Helix says this marks its first-even installation of PLETs this size in more than 6,000 ft (1,829 m) of water using a single-line crane. TheHelixIntrepid did the work.

Four PLETS were installed along with two 8-in. (20-cm) infill flowlines and two 12-in. (30.5-cm) modules for tieback to the Mardi Gras export pipeline. Each mud-matted PLET was 40 ft x 40 ft (12.2 m x 12.2 m) with 20-in. (50.8-cm) connectors for the gas export line and 16-in. (40.5-cm) for the oil line. Each PLET weighed up to 200 tons (181 metric tons) each with the connected 12-in. line. Helix is also installing the 16-in. and 20-in. export jumpers. Spitzer Industries at Greens Bayou, Texas, fabricated the PLETs.

"While we previously have stabbed and laid down PLETs with only a crane, we never before had done so with ones this large and in this water depth," says Ron Tomon, Helix project manager. "This job also required that the 8-in. PLETs be installed by sidestepping beneath a DP drilling vessel. Our project team developed the installation protocol for the PLETs, and theIntrepid crew carried out the plan with precision."

Murphy operates Thunder Hawk with 37.5%. ENI and Statoil each hold 25% and Marubeni holds 12.5%.

More work at Perdido

Deep Down has engineering, produced, and shipped BS Latcher receivers and Messenger Wire kits to Shell's GoM Perdido project to address marine growth problems for the umbilical systems. The $1.5-million contract covers subsea hardware consisting of four BS Latchers with fluid-compensated subsea protective debris covers, nine subsea blind flanges, and 13 Messenger Wire kits with chain jacks and drifts, says Deep Down. The hardware is capable for installation by ROV.

The Messenger Wire kit includes a standard fluid-compensated debris cover, surrounding the BS Latcher Receiver. The unit connects to a messenger wire chain, attached to a surface hang-off device, with an upper blind flange sealing off the I-tube and holding the chain under tension with a chain stop. The chain tension is handled via a surface kit, a chain locker, and chain jacking system that allows the debris cover or subsea blind flange to be held under tension or lowered to the installation vessel in a continuous controlled process. The kit also includes cylindrical drifts with internal anodes and port holes to provide circulation and corrosion protection within the I-tube.

In other Perdido activity, Fugro Chance has completed an acoustic jumper metrology for Oceaneering International Inc.

The Marine Construction Survey Division of Fugro Chance performed the acoustic jumper metrology using a Wideband Medium Frequency (MF) acoustic positioning system. The jumper spanned two pipeline sleds in a water depth of 9,625 ft (2,934 m).

Fugro Chance says the wideband (MF) acoustic positioning system was chosen for a number of reasons including reliability at water depth, ease of use, accuracy and noise immunity of the system, and efficient and cost effective use of hardware.

Luva field current measurement project continues

Statoil has extended Metocean Services International (Pty) Ltd.'s deepwater current measurement project in Luva field north of Trondheim, Norway, for one year. Luva is 240 km (149 mi) west of Bodø in 1,300 m (4,265 ft) of water.

The mooring extends from the seabed to about 50 m (164 ft) below the surface. It was installed in August 2008.

Speaking for the Kupe Joint Venture, Origin Energy Resources Ltd. says an updated schedule calls for first gas from the Kupe field offshore New Zealand to start in 4Q 2009. "Construction of the offshore facilities wells, wellhead platform, pipeline and controls umbilical is complete, and the overall project including the Production Station near Hawera is nearing completion with testing and pre-commissioning occurring later than planned," says Andrew Stock, Origin executive general manager of major development projects. Kupe Gas Project participants are Origin Energy Resources (Kupe) Ltd., 50%; Genesis Energy; 31%; New Zealand Oil & Gas Ltd., 15%; and Mitsui E&P Australia Pty Ltd., 4%.

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