Determination of a seismic and engineering consistent petro-elastic model for time-lapse seismic studies: Application to the Schiehallion field

A relationship between pressure and saturation changes in the reservoir and the corresponding time-lapse seismic signatures is determined from measurements of the produced fluids and downhole pressures at a number of wells. The results from this process also provide an insight into the governing parameters for the rock and fluid physics model which are then compared directly to conventional petro-elastic predictions. The methodology is applied to the Schiehallion field where it is found that the 4D responses to water replacing oil, and gas breakout, follow the predictions of Gassmann fairly accurately. However, the sensitivity of the seismic to increases in pressure is observed to be roughly half as strong as that estimated from standard core plug measurements.