  We present a technique for reconstructing subsurface velocity model changes
from time-lapse seismic survey data using full-waveform inversion (FWI). The
technique is based on simultaneously inverting multiple survey vintages, with
model difference regularization using the total variation (TV) seminorm. We
compare the new TV-regularized time-lapse FWI with the $L_2$-regularized joint
inversion proposed in our earlier work, using synthetic data sets that exhibit
survey repeatability issues. The results demonstrate clear advantages of the
proposed TV-regularized joint inversion over alternatives methods for
recovering production-induced model changes that are due to both fluid
substitution and geomechanical effects.
