Monitoring reservoir compaction from subsidence and time-lapse timeshifts in the Dan field

Reservoir compaction from oil and gas production results in surface subsidence and time-lapse timeshifts. The areal distribution of the subsidence and timeshift data yield information about the magnitude and distribution compaction in the reservoir. Areal measurements of the subsidence bowl obtained using echo sounder and platform GPS data, and time-lapse timeshifts between two 3D seismic data volumes are analyzed to determine the compaction of the chalk reservoir in the Dan field. It is found that the main compaction the reservoir occurs in gas-filled chalks of Danian age. The fact that gas filled reservoir has distinct different compaction characteristics compared to oil filled reservoir, may likely be because the reservoir depletion exerts different load paths dependent on the fluid phase.