Time-lapse seismic modelling

Time-lapse seismic modelling was conducted over a 3-D time-lapse seismic survey area with the aim to assess the feasibility of time-lapse seismic survey and then to extract sensitive seismic attributes for inference of reservoir changes. The velocity and density for the baseline were simply derived from well logs. Those for the monitor line were calculated from reservoir simulation results. The conversion of changes in reservoir conditions to velocity and density was chiefly based on rock physics models for the rock framework and fluids. Time-lapse seismic modelling shows that reservoir changes are significant to be seismically detectable. At least three seismic attributes, amplitude change, cross correlation coefficient and time shift, are identified and can be used to delineate reservoir changes