The energy demands within unconventional resources are exciting issues in stratigraphic-hydrocarbon exploration around the globe. The sub-surface heterogeneous backgrounds and bandlimited seismic information are momentous, and therefore, predicting the true Vp/Vs ratio (Vp/Vs) for incised-valley shale gas play at tuning frequency is a challenge for stratigraphic exploration. The continuous wavelet transform-based (CWT) spectral decomposition (SD) is applied on a 3D seismic data volume towards forecasting the Vp/Vs within a gas field in Indus Basin, Pakistan. The bandlimited spectrum confines the demarcation of reserves. Three types of reservoir facies with two unconventional stratigraphic plays are predicted while performing the lateral variability analyses via Vp/Vs predicting models; including the shale-filled channelized incised-valley stratigraphic play, shelf-to-slope mud-dominated transgressed seal facies; and the carbonate stratigraphic play. The bandlimited Vp/Vs modelling (VM) shows imaginary spots due to fine-tuning possessions of ambiguous lithology and fluids. The 20-Hz CWT-based Vp/Vs model (CWT-VM) detects and resolves the real-time visualizations of shale-filled incised-valley, geometrical configurations, potential reservoir fluids, and 32-Hz delineates laterally distributed carbonates traps. The predictable model-based (CMB) arithmetical plot predicts 84 % correlation with Vp/Vs and reservoir thickness as 1.42 and 33 m along the extensional faulted blocks. The 20-Hz CWT arithmetical plot proved as a robust tool for accurate imaging of seismic-to-well tie, i.e., 89 % correlating prediction for true Vp/Vs as 1.42 highlights the gas-bearing reservoir, and 62 m enhanced (true) thickness determinations. This workflow has strong implications for horizontal well drillings within the extensional regimes of unconventional stratigraphic plays and serves as an analogue for global clastic depositional systems.