Abstract A 4D seismic survey was acquired over Genesis Field, deepwater Gulf of Mexico, in October, 2002 specifically for reservoir monitoring and field management. The acquisition criteria replicate the pre-production baseline survey. Coprocessing baseline and monitor surveys minimized differences between surveys except those related to production. Interpretation of reflection and acoustic impedance volumes indicate that the 4D project will add significant value to the field. The interpretation of 4D data on the field's five primary reservoir sands has resulted in: • Observed production-related time-lapse anomalies including a) changes in reflection strength due to fluid movement and pressure reduction b) an increase in travel time of up to 10 ms at the top of the producing interval due to reservoir compaction and overburden dilation. • Identification of up dip potential and/or its risk reduced in three reservoirs. • Resolved connectivity uncertainties in several reservoirs leading to better understanding and modeling of reservoir behavior. Preliminary assessment of the 4D project indicates significant value added by modifying field operations: • One anticipated sidetrack has been eliminated saving over $10 million dollars. • The geological risk of one sidetrack was reduced and the original estimate of recoverable volumes increased. At least two future sidetracks should be affected similarly. • Adjustments to the reservoir simulation should lead to better well placement, improved recovery estimates, and better reservoir management.