Mapping of water and gas injection areas through modeling and interpretation of 4D seismic from reservoir simulation models

- Three simulations are done with different arrangements of water and gas injection.
- From simulation results, synthetic time-lapse seismic data is computed.
- Amplitude results are analyzed to differentiate water and gas injections.

Using an integrated approach of reservoir simulation, rock physics and seismic modeling, the present study analyzes the influence of changes in pressure and fluid saturation on synthetic time-lapse seismic sections. The forms and occasions in which these changes can be detected on 4D seismic are studied, to help in the characterization of the fluid flow inside the reservoir. To analyze these effects, reservoir production simulations were conducted in a geological model of a sandstone reservoir in the Campos Basin, offshore SE Brazil. Through direct petro-elastic and seismic modeling, 4D impedance volumes were created using simulation results, and corresponding synthetic seismic volumes were computed. Simulations of both water injection and gas injection scenarios were conducted in order to quantify the differences between oil-water and oil-gas substitutions and investigate how they affect the seismic amplitudes in a sandstone reservoir. The interpretations allow the definition of patterns to identify pressure and saturation related anomalies and to distinguish areas of water and gas injection.