Mitsubishi Heavy Industries (MHI) has received an order for two vessels capable of three-dimensional (3D) seismic data acquisition for sea bottom resource exploration from Petroleum Geo-Services (PGS).
The contract, which was signed on April 14 in Oslo, also provides an option to PGS to order another two vessels in the future. Delivery of the two ships on order is slated to begin in the spring of 2013.
The vessels are the Ramform W-class, the newest generation in the Ramform series featuring advanced 3D seismic data acquisition/analysis capability. The 104-metre vessels have a very wide breadth of 70 metres. For quiet operation, the vessels will adopt diesel electric propulsion.
The Ramform W-class vessel employs multiple streamer cables, each several kilometres in length, towed from the vessel's stern. The cables contain a vibration sensor known as a "hydrophone" which detects echoes of sound waves emitted from sound sources and bounced back from the sea bottom and stratum boundaries. The detected echoes are used for 3D seismic analysis. The new Ramform vessels ordered by PGS have a 30-metre wider stern compared with existing vessels; this feature permits the deployment of a greater number of streamer cables – up to 24 lines -enabling exploration of a wider area at one time.
