A recent contract renewal for the small UK-based company WGP Group and its partner Thalassa Energy Services is a reminder that the first life of field seismic (LoFS) project on BP's Valhall field offshore Norway has been ongoing since 2003. The companies have been providing the seismic source service for the project since the inception with an average of two surveys per year.
WGP Group is also on its third extension working on a LoFS project for the Chirag Azeri Reservoir Seismic Project (CARSP) where BP is the operator in partnership with Azerbaijan International Operating Company (AIOC) in the Caspian Sea. Since 2007 WGP has designed, installed, and operated a bespoke system capable of repeat all-azimuth ocean bottom cable (OBC) seismic surveys enabling AIOC to monitor reservoir fluid movement.
Owing to the size of the Azeri-Chirag- Guneshli (ACG) oilfield, one of the world's largest producing offshore fields, WGP is using OYO Geospace's GERI 4C OBC on a semi-permanent basis. WGP has modified the platform supply vessel Citadel into an OBC vessel with the capability to deploy and retrieve up to 132km of cable across multiple survey areas, monitor receiver placement via ROV, and provide the seismic source. Between 2007-2009 three base line and two repeat surveys, each with a total average spread of 540km2, were performed with 195,000 total shots acquired. Phase two, begun earlier this year, includes three new base lines and one repeat survey with total shots estimated at 250,000.
Despite the obvious success of these projects, life of field seismic as a technology for industry-wide use remains in the doldrums. OE
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