Andrew Seismic Reservoir Surveillance

A-17 ANDREW SEISMIC RESERVOIR SURVEILLANCE Overview A 4D (time lapse 3D) seismic survey was acquired in May 2001 across the Andrew field in the UKCS. A weak seismic 4D response was observed which was compared against two contemporaneous time lapse production logs. The close agreement between the results of these complimentary surveillance methods allowed the validity and calibration of the water and gas saturation changes to be tested across the whole field. The production logs provided indications of fluid flow at the wellbore whilst the 4D provided its regional perspective. The application of this method across the whole field has