Implementing adaptive scaling and dynamic well-tie for quantitative 4-D seismic evaluation of a reservoir subjected to CO2 enhanced oil recovery and associated storage

Abstract

History-matched simulation modeling can be used to estimate field dynamic reservoir properties and connectivity between wells. However, results are less accurate away from the well locations where the field data are obtained. 4-D seismic data can help improve the accuracy between wells and across the field. This study used data from an oil field undergoing active CO2 injection for enhanced oil recovery and associated CO2 storage. The change in seismic amplitude, changes in inverted P-wave velocity, and impedance in the reservoir layer are in turn correlated with the pore volume scaled changes in the dynamic reservoir properties at well locations. Impedance and velocity changes yielded the most robust correlations. The correlated linear relations at three injectors were used to invert for the pore volume scaled changes in saturations and pressure between wells and across the field. Validation at the producer yielded 69% accuracy. By tying the 4-D seismic with the reservoir properties at the injectors using repeat pulsed-neutron log data and the simulation models, a good level of confidence is established in the inverted pore volume scaled changes in the dynamic reservoir properties in the interwell spaces. The inverted reservoir properties can be used to further history-match the simulation model to improve the interwell prediction of the long-term fate of the associated CO2 storage.