Schlumberger Supplies Subsea System to HMC Offshore Angola

Schlumberger has been awarded a contract by Heerema Marine Contractors to supply a real-time riser tension monitoring system for nine single leg hybrid risers (SLHR) for a major project offshore Angola.

"This system enables real-time riser tension and curvature monitoring during operation and the installation process optimizing the overall riser integrity management program," said Andy Hendricks, vice president, Schlumberger Subsea. "The award is a result of significant development and qualification programs in which we have participated in the last two years."

The nine SLHR are located around the FPSO turret mooring and connected to it by flexible jumpers. The SLHR are free standing and are maintained in tension by a buoyancy tank. As part of the project, Schlumberger will install its subC-collar tension and curvature monitoring system located on each riser immediately below the buoyancy tank.

The subC-collar units are powered by local ROV replaceable batteries, which also include an acoustic telemetry module to transmit the riser tension data to two receiving units located on the FPSO. This capability helps to avoid shadowing effects from the risers and flexible jumpers.

The award is one of several recent successes achieved by Schlumberger in subsea integrity surveillance. These include fast-track delivery of a complete riser monitoring system -- including environmental monitoring -- for a North Sea operator using a high specification riser; and deployment in West Africa of the subC-pts* non-intrusive pressure and temperature system in ROV- portable form to meet test and safety obligations on subsea trees with limited intrinsic pressure-test capability.