Abstract To obtain robust geophysical indicators for hydraulic stimulation in unconventional shale gas reservoirs, this study investigated the integrated seismic prediction of multiple key geological and engineering sweet-spot parameters in tilted transversely isotropic media, including the tilted fracture density, squared P- to S-wave velocity ratio (squared PSR), brittleness index, and tilted differential horizontal stress ratio (TDHSR). Well-log analysis indicated that the squared PSR is effective for lithologic discrimination and exhibits high sensitivity to organic matter enrichment. When integrated with the tilted fracture density, the squared PSR can delineate intervals favorable for stimulation. A reformulated PP-wave reflection coefficient approximation, which enabled the estimation of the tilted fracture density from the azimuthal amplitude differences and the squared PSR from the isotropic seismic component, was derived. Based on the predicted parameters, a new TDHSR expression incorporating the tilted fracture density, squared PSR, and fracture inclination angle was used to evaluate the hydraulic fracturing potential. The performance of the proposed seismic inversion framework implemented with Lp-quasi-norm sparsity regularization was examined through three numerical model tests under different signal-to-noise ratio conditions. The field application to a shale reservoir in southern China showed that the proposed method can effectively predict multiple sweet-spot parameters and delineate fractured gas-bearing shale intervals and favorable stimulation zones.
Zhao et al. (Wed,) studied this question.