Estimation of pressure and saturation fields from time-lapse impedance data using the ensemble smoother

Abstract

This paper introduces the use of the ensemble smoother as a method to invert time-lapse seismic data into pressure and saturation fields. The proposed method uses engineering information described in terms of reservoir flow simulations to generate samples of the prior uncertainty space. Subsequently, these samples are corrected using the time-lapse seismic as conditioning data. The problem is formulated in terms of generating an ensemble of pressure and saturation fields sampling the posterior uncertainty space. The proposed method is very flexible and computationally easy to implement. It has very few requirements in terms of the forward model (reservoir flow simulations and petroelastic modeling). This makes the method straightforward to integrate with existing commercial tools. © 2014 Sinopec Geophysical Research Institute.