Seven separate infield pipelines, each about 5 km long, and a further 52 km of 8-in. gas export pipeline were installed earlier this year to link production between the BLP "A" facilities on the Captain Field and the Area "B" template. The field is located in the North Sea.
Coflexip Stena Offshore (CSOL) was responsible for the installation and the CSO Apache vessel installed the field lines. The prefabricated "stalks" were completed at the Evanton spool base during the past winter and reeled onto the Apache's main and secondary reels (to accommodate the 3-in. piggyback pipelines). The field was located eight hours steaming from the Evanton base.
The speed of installation took advantage of the short weather windows in the North Sea. The sling shot pipeline routing on the infield pipelines skirting around the floating prod-uction, storage, and offloading (FPSO) vessel moorings helped to minimize both the cost and the potential interference between the existing production operations and the new installation activities.
The arrival of the Apache infield was followed by the trenching support vessel, Normand Pioneer, while the utility vessel, Skandi Inspector, provided for survey needs for the pipelay and trenching operations, as well as supporting some of the diverless construction, pipeline flooding, gauging and wet end hydrotesting operations. The support helped pull forward some of the work originally planned during the later tie-in stage and reduced the initial resource demand onboard the BLP "A." The pipelines were tested, allowing the BLP "A" jacket and Area "B" template installation to proceed.
Given the importance of local fishing activity, the Scottish Fisheries Federation (SFF) played a role by providing liaison skippers and guard vessels to ensure regular updates for the fishing community, while ensuring protection of the subsea infrastructure throughout the intermediate stages of construction.
After installation of the BLP "A" topsides, CSOL continued with the installation of three control umbilicals, the Captain tee, and the SSIV structures. The firm was scheduled to complete the tie-in, testing and protection of over 40 spool pieces in recent months. Other work to be done on the field was rock dumping on the third party crossings and the Frigg tie-ins.
