Helix Producer 1 DTS Mooring and Installation Helix Producer 1 DTS Mooring and installation SITE DETAILS: Location: Green Canyon Block 237 Region: Phoenix Field, GOM Water depth: 650-m (2,133-ft) SYNOPSIS: The installation of the Helix Producer 1’s disconnectable transfer system (DTS) in Green Canyon Block 237 of the Phoenix Field required top-notch engineering for its completion. WORK SCOPE: InterMoor’s original work scope revolved around the installation of the preset mooring system and its subsequent hook-up to the DTS buoy. The initial plan was to bring the Helix Producer 1 and the buoy in to the field at the same time, the latter already occupying its position in the port-side cage. However, InterMoor’s scope expanded significantly when it was decided to install the DTS buoy ahead of the Helix Producer 1’s arrival, an undertaking described as wet-parking the buoy. The DTS buoy, which weighs approximately 300-t, was equipped with a six-point chain-and-wire mooring system designed to be preset. In addition, attached was a 68-t clump weight in the form of a spreader bar with chains suspended beneath the structure on a wire tether nearly 600-m long. The approximate water depth at the DTS’s center measured 650-m (2,133-ft).
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Helix Producer 1 DTS Mooring and installationSITE DETAILS:Location: Green Canyon Block 237Region: Phoenix Field, GOMWater depth: 650-m (2,133-ft)
SYNOPSIS:The installation of the Helix Producer 1’s disconnectable transfer system (DTS) in Green Canyon Block 237 of the Phoenix Field required top-notch engineering for its completion.
WORK SCOPE:InterMoor’s original work scope revolved around the installation of the preset mooring system and its subsequent hook-up to the DTS buoy. The initial plan was to bring the Helix Producer 1 and the buoy in to the field at the same time, the latter already occupying its position in the port-side cage. However, InterMoor’s scope expanded significantly when it was decided to install the DTS buoy ahead of the Helix Producer 1’s arrival, an undertaking described as wet-parking the buoy. The DTS buoy, which weighs approximately 300-t, was equipped with a six-point chain-and-wire mooring system designed to be preset. In addition, attached was a 68-t clump weight in the form of a spreader bar with chains suspended beneath the structure on a wire tether nearly 600-m long. The approximate water depth at the DTS’s center measured 650-m (2,133-ft).
InterMoor Inc.900 Threadneedle, Suite 300
Houston, TX 77079Phone: 832-399-5000
Fax: 832-399-5001www.intermoor.com
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CHALLENGES:Wet-parking the DTS buoy provided a series of interesting challenges. Potential issues installing the buoy together with its clump weight were not anticipated, although it was clear that without the moorings and risers there would be an insufficient ballast to set the buoy down at a safe depth.
SOLUTION:InterMoor and Helix Energy Solutions’ engineers presented the idea of a temporary ballast system in the form of four chains weighing a total of 110-t. The chains could be attached directly to the underside of the structure.
CONCLUSION:The DTS operation was performed in two days without incident and completed in November 2009. The moorings were preset at approximately the same time. In January 2010, the four risers were laid down on the sea floor. During March and April 2010, the risers and two umbilicals were pulled into the DTS buoy and then the moorings were hooked up, with ballast being progressively removed throughout the two processes. Finally, in late April 2010, the Helix Producer 1 took up position in the field and claimed rights as the first ship-shaped production unit to enter service in the Gulf of Mexico.
Water depth: 650-m (2,133-ft)Installation: Riser buoyRiser pull-ins: Four (4)Umbilical pull-ins: Two (2)Mooring legs: Six (6)
