A robust high-resolution time-lapse simultaneous joint migration inversion process applied to synthetic data from grane field

Abstract

Simultaneous Joint Migration and Inversion (S-JMI) is an effective time-lapse tool for reservoir monitoring, which combines a joint time-lapse data processing strategy with the Joint Migration Inversion (JMI) method. In S-JMI, fine details are not expected in its inverted velocity model, as it only explains the propagation effects in the data, while the scattering effects are explained by the inverted reflectivity model. However, for time-lapse processing, high-resolution time-lapse velocity differences are usually a demand. Therefore, in order to get more localized time-lapse velocity differences, we propose a robust high-resolution S-JMI process by using the time-lapse reflectivity-difference as an extra constraint during S-JMI. This constraint makes a link between the reflectivity- and the velocity-difference by exploiting the relationship between them, which can also be explained as a constraint on density. In the end, with a highly realistic synthetic model based on the Grane field from offshore Norway, we demonstrate a more localized inverted time-lapse velocity difference using the proposed robust S-JMI, compared to the regular SJMI.