Seismostratigraphic Evaluation of Lower Cretaceous Unconventional Shelf‐Edge Rifting Indus Delta: Instantaneous Lateral Thickness and Gas Saturation‐Constrained Dynamical Simulations

ABSTRACT With its distinctive extraction technology and substantial influence on energy markets, shale gas is a major, unconventional, and quickly developing area of the global energy sector. It is seen as an important but complicated energy source that fills the gap for future energy solutions. These unconventional energy systems are developed within the diversity of geological systems, for example, shelf‐edge delta, and therefore, the shale gas‐bearing shelf‐edge delta (SDelta) forms excellent sedimentation configurations for the development of stratigraphic‐based shale gas‐bearing sedimentary systems. However, the band‐limited impedance restricts the resolution of sub‐seismic seismostratigraphic reflection configurations, for eample, parallel, divergent, and so on, gas saturation and pressure breakthroughs, stratigraphic pinch‐outs, basin development zones, simulated density (SDensity), simulated velocity (SVelocity), simulated thickness (SThickness), and seismic‐based gas saturation (SeisGas) (%), which facilitate seismostratigraphic assessments of sedimentary influxes for SDelta. This research applies the spectral wavelets and high‐tech broadband spectrum decomposition‐founded thickness besides gas saturation‐controlled seismostratigraphic simulations (STGasSim) to quantify the Indus SDelta. Spectral wavelet 37 Hz resolves a 12 m thick channel complex and lateral impedance anomaly along the organically rich shale zone but failed to image the pressure breakthroughs. STGasSim‐based 1400–1466 m/s SVelocity at 60%–68% SeisGas implicates the onset of permeability, moderate influxes and migration, and hence, progradational facies. STGasSim‐based ∼1344, 1365, to 1395 m/s SVelocity at 76% to 80% SeisGas implicates pressure breakthrough, highest permeability, migration, and highest influxes, and hence, aggradational facies. STGasSim‐based ∼3.34, 3.38, to 3.4 g/cm 3 SDensity at 60%, 64%, and 68% SeisGas implicates the onset of tectonic subsidence, moderate fractures, and hence, aggradational stratigraphic pinch‐out reservoir facies. STGasSim‐based 3.38–3.41 g/cm 3 SDensity at 76%–80% SeisGas implicates gas saturation breakthrough in dense fractures. The lateral impedance anomaly serves as the direct shale gas indicator (DSHI) for aggradational stratigraphic pinch‐out facies of SDelta, and hence, it might assist equally an equivalent aimed at Onshore Indus SDelta as well as global SDelta.