Elastic impedance

It is now commonplace for 3-D data sets to be processed as partial offset volumes to exploit the AVO information in the data. However, there has been significant asymmetry in the way these volumes could be calibrated and inverted. The amplitudes of near-offset, or intercept, stacks relate to changes in acoustic impedance and can be tied to well logs using synthetics based on acoustic impedance (AI) or inverted, to some extent, back to AI using poststack inversion algorithms. However, there have been no simple analogous processes for far-offset stacks.