WorldOil

France: Subsea slug catchers provide flexibility for deep water

Subsea processing technologies have moved forward quickly in the last few months. Several projects including subsea boosting, subsea separation or subsea gas compression are foreseen or already sanctioned. The development of gas fields usually requires the use of slug catchers. For large flowrates or when the length of the multiphase line is long, this equipment can be very large and require heavy structures, up to several thousand tons. Installing them on the seabed would be preferable to installing them on topsides or at shore. The first Subsea Slug Catcher (SSC) was installed in 1985 by Texaco on the Highlander field in the North Sea. This equipment, in 550 ft (168 m) of water, is used for a limited slug volume. Total E&P recently awarded Saipem an SSC feasibility study, covering very large slug volumes and water depths. This article discusses using such systems for several offshore field development scenarios...