Subsea 7 and 2H Launch Grouped SLOR Deepwater Riser Concept

Subsea 7

Subsea 7 in collaboration with 2H Offshore has launched a new deepwater riser design, the Grouped SLORTM. This is a further development of the 2H Single Line Offset Riser arrangement that has been field-proven on the Kizomba-A & B projects and will soon be installed on Petrobras' P-52.

2H has conceived and developed the Grouped SLOR system with extensive design and structural analysis work. EPIC (engineering, procurement, installation and construction) contractor, Subsea 7, has now invested in the qualification of the concept including detailed engineering analysis and hydrodynamic tank tests such that they can propose it as a SURF (subsea umbilicals, risers and flowlines) solution for current and future deepwater field developments.

John Mair, Global Technology Manager of Subsea 7, commented, "We were particularly keen on this concept because it suits the capabilities of our construction fleet including the new vessels Seven Seas and Seven Oceans thus allowing us to provide a field optimised solution. Additionally such a system can be installed using our tow-out capability maximizing installation flexibility."

The arrangement allows a large number of SLORs to be located adjacent to each other without the risk of clashing. This is achieved by a lightweight guide frame that constrains the lateral movements of all SLORs. The system is optimally suited for field developments where the number of risers is high and can be optimized so that the riser angle is splayed out below the frame to optimize field layout and interface with seabed flowlines.

Steve Hatton, Principal Director of 2H Offshore, said, "This system compares favorably against the hybrid bundle system such as used on Girassol in that the design complexity of the system and individual components is greatly reduced. This has important benefits with respect to procurement, schedule and local content issues".

The Grouped SLOR system will be on display at DOT in Houston, Texas in November where both 2H and Subsea 7 will be exhibiting.