Important features / notes:

This project was for Chevron offshore in Thialand. The helical coils were made from 150NB Sch 40 pipe with supports and saddles made from 150NB Sch 80 (9.5mm) pipe. The equipment consisted of 2 twin start helical coils interconnected at the top. The coils has very tight tolerances with only a 12mm annular gap between coils for inserting inner coil into outer coil. The entire assembly weighed 24 tonnes. Overall size is 3700mm in diameter and over 7500 mm in length.

Since the coils were twin start, the rolling and forming needed to be exact so that coils could be intertwined without any gaps and stitch welded together. Supports were made from stainless steel grade 253 MA (16mm) which is a micro-alloyed stainless steel with high temp properties. All welding was carried out to qualified weld procedures to ASME Boiler and Pressure Vessel code.

Project completion :