Using slowness and azimuth fluctuations as new observables for four-dimensional reservoir seismic monitoring

Recently, a lot of efforts has been done in seismology and geophysics to track and monitor sub-surface property variations such as velocity, fluid pressure or saturation. In 4D monitoring, the two main observables are velocity and amplitude variations. For a given reflection, variations are classically monitored using wavelet travel time and amplitude. Today, combined travel time and amplitude variations measures are possible. In this paper, we present an array processing method to measure new observables linked with the velocity variations in 4D monitoring such as the slowness at both the source and the receiver sides.