|Publisher||Offshore Technology Conference||Language||English|
|Content Type||Conference Paper|
|Title||Design Features for Wye Sled Assemblies and Pipeline End Termination Structures to Facilitate Deepwater Installation by the J-lay Method|
|Authors||K.C. Dyson, INTEC Engineering Ltd; W.J.McDonald, BP America Inc; P. Olden, BP America Inc; F. Domingues, Pegasus International Inc..|
Offshore Technology Conference, 3 May-6 May 2004, Houston, Texas
|Copyright||2004. Offshore Technology Conference|
This paper presents an evaluation of some novel installationrelated design features required for the installation of fourteen in-line wye sled assemblies (WSAs) and five pipeline end termination structures (PLETs). The WSAs and PLETs were designed for installation by the DCV Balder utilizing J-lay techniques. WSA features included structural frames designed to flex, hinged yokes for anchoring buoyancy modules, and yoke stoppers to provide stability for the WSA pipe-spool during upending. Due to tower width limitations, some of the larger WSAs had sliding, or separately installed mudmats.
PLETs were designed with hinged mudmats for 'first-end' installation lay-away, but also had to be capable of second-end recovery to surface for repair and re-installation, if necessary.
BP and its partners are developing several deepwater prospects in the Gulf of Mexico. These include the Holstein, Mad Dog, Thunder Horse and Atlantis floating production facilities in water depths ranging from 4500 feet to 7300 feet. Oil and gas will be exported via the Mardi Gras Transportation System. The deepwater development consists of a combination of 16-inch to 28-inch oil and gas trunk and lateral pipelines, tied-in using piggable wyes.
At the time of the release of this paper, the Balder has successfully installed eight WSAs and two PLETs in the Southern Green Canyon Area. Typical WSA and PLET arrangements are shown in Figures 1 and 2 respectively.
The initial challenge for tie-in structure design was the non-existence of suitable vessel installation equipment, because Heerema, the selected installation contractor, was still designing, fabricating, and modifying the Balder's J-lay equipment. Anticipating installation restrictions on WSA and PLET design consequently required intense cooperation between the design team and the installation contractor.
The team's primary objective was to develop structures that would allow the tie-in of a lateral pipeline. The tie-in was to have the following requirements, as a minimum:
|File Size||734 KB||12|