Schlumberger licenses Brent surveyNews // July 14, 2000
The Brent field is located 160km north east of the Shetland Islands. It was discovered in 1971 and has been in steady production since 1976.
The Brent 4C survey, acquired by two Schlumberger specialist 4C seismic vessels, the Geco Angler and Geco Bluefin, in October and November 1999, covers 62.4 square kilometres.
The primary objective of the Brent 4C survey was to use the PZ data for improved imaging of the Brent slumps, which form a complex area on the eastern side of the field.
The new PZ migrated data have been compared with 96-fold towed streamer data acquired in 1995 on a line-by-line basis. The new PZ data provide consistently better reflection continuity, fault definition and structural imaging.
Factors contributing to the improvement include better demultiple by combining the P and Z (hydrophone and geophone) recordings, wider azimuths that provide better subsurface illumination, and better positional control through the use of seabed cables.
Shell geophysicist Stuart Arnott commented: "In comparison with our towed streamer data, the new 4C data provide significantly improved structural imaging of the complex slumped areas of the (Brent) field. We expect this to lead to improved targeting ofundeveloped reserves and reduced drilling costs."