《least squares reverse time migration》.pdf

/ Least-Squares Reverse-Time Migration g r Gang Yao* and Helmut Jakubowicz, Imperial College London o . g e s. Summary where is the modeled wavefield, is the Greens y r function, is the source signature, is position, is the a r We present a matrix-based implementation of least-squares source location, and is angular frequency. The recorded b i l reverse-time migration in which the predicted data are data, , are then back-propagated into the subsurface using / / : generated using a modified source wavelet. We also show p the adjoint of the modeling operator, , giving t t that the combination of the least-squares formulation and h t reverse-time migration leads to an estimate of the a ( | ) ( ) (,)= ; , . (2) e reflectivity which is consistent with a deconvolution s U imaging condition; this in turn provides higher-resolution The imaging step generates an estimate of the reflectivity, f o and more accurate amplitudes than conventional reverse- (), by relating and to each other at all points in the s