A 3D Ray-based Pulse Estimation for Seismic Inversion of PSDM Data

We develop a methodology for estimation of the point-spread function of prestack depth migrated data (PSDM). The parametrization of the point-spread function is given by a ray-based approach which incorporates the effects of wave propagation through the use of illumination vectors. The only unknown factor in the expression for the point-spread function is a 1D pulse. This pulse is estimated from reflection coefficients in wells, and co-located PSDM data using a least squares approach. The estimate of the point-spread function is the first step towards seismic inversion of PSDM data. In comparison to traditional wavelet estimation, the model using PSDM data has a larger range of validity, i.e. we are able to remove the assumption of a horizontally layered earth. In examples we show that our method is identical to the 1D convolution when the earth has a constant dip, but gives an improvement when this assumption is violated.