Sensitivity analysis of 4D seismic attributes to calibrated petroelastic models under dynamic reservoir conditions

A well-calibrated petroelastic model is vital for 4D seismic monitoring, linking reservoir property changes to 4D seismic attributes. This study assesses the sensitivity of 4D attributes to saturation and pressure changes using common dry rock frame models based on empirical, inclusion, contact, and cementation theories. While all models fit static sonic logs well, their 4D responses to dynamic properties differ significantly. For saturation changes, the Critical Porosity model and the 5th percentile of the patchy cement model yield the lowest and highest 4D responses, respectively, with cementation type having minimal impact. On the other hand, pressure-induced responses vary significantly with cementation and hyperparameter variations. Stress sensitivity models based on compliance and Hertzian theories show differing pressure-related 4D responses. These findings emphasise the importance of choosing suitable dry rock frame models and consider their uncertainties for reliable 4DQI.