| Seismic waves get attenuated and dispersed as they propagate in the earth. This attenuation of waves is mostly due to spherical divergence and friction of rock particles. In order to obtain an image of the subsurface with good resolution such factors should be considered. In this research, prestack depth imaging is performed using the Phase Shift plus Interpolation (PSPI) technique after modifying it to ac- commodate attenuation. The compensation is performed by deriving the waveeld extrapolators in the frequency-wavenumber (f -- k) domain. The extrapolators ar rst derived to obtain an image without any compensation in the (f -- k) domain i.e., acoustic PSPI. Next, the extrapolators are modied to compensate for at- tenuation losses, (i.e., visco-acoustic PSPI). Both phase velocity and absorption Q-model are used in waveeld extrapolation to obtain seismic images with com-pensating operators. Operator compensation requires a trivial cosine transform applied on the non-compensating operators in order to compensate for the eect of absorption and dispersion, thereby, increasing the spatial resolution of the sub- surface image obtained. In addition, the assessment of seismic images is addressed in this thesis. The assessment of such important images is mostly done subjec- tively in practice. Here, a method is developed to evaluate the quality of seismic images objectively by taking into consideration the noise and spatial resolution (the amount of blur). Here we consider non-reference based image quality assessment methods because in most practical cases, a reference image is not available. |
