In many areas, depth imaging of seismic data is required to construct an accurate view of the reservoir structure. This is especially true in areas of complex geology and areas with salt tectonics. Having identified the reservoir structure, we of course want to extract further information on lithology, reservoir quality, and fluids. This can be achieved by seismic amplitude variation with offset (AVO) inversion. Traditionally, depth-imaged data are inverted by converting it back into the time domain to enable the seismic data to be represented by convolution with a consistent wavelet, varying only slowly with both time and spatial location. We will describe an alternate approach that allows us to invert the seismic data directly in the depth domain, where it has been correctly located by the depth imaging. This approach also allows us to account for the variability in the image amplitudes that arise due to the complex geology and the spatial variations in the acquisition geometry.
This new approach to inversion is demonstrated on synthetic model data, and compared with results obtained from conventional time-domain inversion.