Estimation of time-lapse velocity changes using Gaussian reconstruction

A key task in 4D seismic analysis is to resolve changes in subsurface velocity ΔV/V that affect both imaging in the monitor data and our interpretation of time-lapse amplitudes. This study introduces a new approach to recover ΔV/V using a Gaussian mixture model. The Gaussians are found to be better representative of the property fields than other choices such as B-splines. This approach is tested by application to a North Sea field, where geomechanical effects are active. Recovery of ΔV/V from three different time-shift estimates, using three approaches is firstly compared with Gaussian reconstruction. A second comparison estimates ΔV/V directly from the trace data. In these tests, the new approach compares favourably in the presence of noise, and is relatively simple to implement.