Specialist engineering company, STATS Group, has completed an 18 month design, manufacturing and installation project to enable the tie-in of a fifth pipeline on Statoil’s Troll A Platform. Statoil’s Troll A platform, located off the west coast of Norway, utilises a system of seal tubes to tie-in risers which are run down the inside of a dry concrete leg. The seal tubes were concreted in place at the base of the riser leg on the gravity base structure in 1991. There are seven seal tubes – four designed for large bore pipe up to 36” - and three designed for smaller diameter pipe up to 20”.