Practical techniques for time-lapse AVO inversion

Abdul-Nassir Saeed, Laurence R. Lines, Gary F. Margrave

Successful prediction and mapping of fluid saturation and pressure changes in hydrocarbon reservoir depends mainly on accurate relative amplitude processing of seismic data vintages that meet AVO complaints as well as a practical time-lapse AVO inverse scheme.

In this report, several time-lapse AVO inverse schemes are proposed in order to improve estimation of elastic physical model parameters, provide better inverse section in presence of noise and prove their robustness in terms of time calculation and estimation of the change in model parameter estimation.

Inversion of seismic reflectivity difference only of time-lapse seismic data surveys is a quick method in time-lapse AVO inversion. Sequential cross-reflectivity constraint inversion is a robust time-lapse AVO inversion schemes that can be implemented to constraint noise effect on the data and to ensure smooth change in estimating reservoir attributes from time-lapse inversion.

Total inversion of the differences schemes are other time-lapse AVO inverse techniques that can be carried out into two different inverse objectives. These are: Inverting of time-lapse AVO seismic data for estimating of elastic physical model parameters of monitoring line and time-lapse reflectivity model parameters changes of base and monitoring lines. While a second total inversions of differences can be implemented to estimate elastic physical model parameters of base line along with time-lapse reflectivity model parameters changes of base and monitoring lines.

The proposed time-lapse inverse schemes in this report are tested on synthetic seismic data. These proposed inverse techniques are to be tested using real time-lapse seismic data from Pikes-Peak heavy oil fields that are being processed for AVO complaints and optimal repeatability.