Quick Impact of New 4D over the Halfdan Field, Danish North Sea

A new repeat time lapse seismic survey was acquired in 2012 over the Halfdan Cretaceous Chalk Formation oil field, and the 800 km2 surrounding area, located in the Danish North Sea Central Graben, approximately 250 km west of the Danish west coast. The main objectives of the repeat 4D were to understand the lateral and vertical sweep, identify unswept areas, guide future well interventions and to clarify the reservoir model. A key technical objective of the new time lapse was to deliver a fast track 4D difference volume 11 weeks after the last shot with the aim to influence further processing steps and quickly integrate the 4D into the asset management. The volumes were quickly compared with the simulation data and the previous 2005 time lapse seismic focusing on the changes in lateral & vertical sweep. Field-wide and reservoir specific examples of the time lapse response from 2005 to 2012 are presented.