PGS Marine Geophysical completes high technology North Sea survey

PGS Marine Geophysical announces the successful completion of a high density, single-source, multi-azimuth 3-D seismic survey over the Ellon, Grant, Forvie and Hild Fields in the Northern North Sea. The work was carried out on behalf of the operators TOTAL E&P UK and Norway.

In order to achieve the object of improved resolution and improved signal-to-noise ratio, PGS utilised their HD3DTM ( High Density 3D) acquisition system. The Ramform Victory which used 14 streamers, 4500m in length, towed just 37.5 m apart completed the single source survey. The configuration allowed a close spacing of 18.75m, which reduced the aliasing of higher frequencies in the cross-line direction. The spacing was obtained while maximising the signal-to-noise with the benefit of full-fold processing.

In addition to the 600 sq. km of the main survey, in order to obtain superior imaging of the sub-surface in the structurally complex Hild Field area, an additional 200 sq. km of data were acquired in a multi-azimuth direction across this area. This technique uses data acquired in two or more directions to improve signal quality as shown by similar acquisition and results over the Varg Field in Norway.

The acquisition of over 800 sq. km of HD3D data was completed in 8 days after start of production, during which there were no lost time incidents. Even with 63 km of streamers in the water in a spread of 14 streamers less than 1 km width, technical downtime was only 5%.