The inversion of seismic velocity using a partial-offset stack with well-log constraints

A new partial stack inversion algorithm has been developed to simultaneously estimate P-wave and S-wave velocities from P-wave reflection seismic data. First stacking the near and the far angle seismic data separately, we use the partial stacks for inversion. This method is based on the relationship between the variations of seismic wave amplitudes with incidence angle and the elastic parameters. Thereby, P-wave and S-wave anisotropic models are derived from seismic sections for different incidence angles. Using the P- and S-wave models, inverted separately using the corresponding seismic sections, the P- and S-wave velocities at normal incidence can be obtained from seismic anisotropy theory. To ensure the stability of inversion and to reduce the possibility of non-unique solutions, this method employs the joint constraints of well logs and poststack structural layer interpretations, and performs prestack noise elimination while preserving as much amplitude information as possible.