Estimating reservoir properties from 4d seismic data

Abstract

Method for deriving a reservoir property change data volume from time shifts used to time-align 4D seismic survey data (). The time alignment is performed on at least one angle stack of 4D data to determine a time-shift data volume (). When multiple angle stacks are used, the time shifts are corrected to zero offset. A running time window is defined, and within each window the time shifts are best fit to a straight-line function of time (depth), one angle stack at a time (). The slopes from the straight line fits from different angle stacks are averaged at each voxel in the data volume, which yields a reservoir properties (Δν/ν) data volume (). This data volume may be filtered with a low-pass filter to improve signal-to-noise (). The resulting data volume may be merged with the 4D data volume to expand its bandwidth (), or it may be converted into a reservoir saturation and pressure change data volume () using a rock-physics model ().