Seismic frequency controls to characterize the lower-cretaceous incised-valley system, Indus Basin, SW Pakistan: Spectral decomposition as a direct hydrocarbon indicator

Abstract

Seismic properties can assume a vigorous part in the portrayal of the incised-valley reservoirs the world over. But, accurately optimizing the attributes within the stratigraphically heterogeneous fluvial system is significant, and thus, delineating the porous sandstone is the challenge for prospect delineation. During the forecast of stratigraphic traps, the resolve is to select the frequency band, which can accurately image the thickest part of the reservoirs. The continuous wavelet transforms (CWT) of spectral decomposition (SD) tool is applied for enlightening the incised valley from Miano gas field, SW Pakistan. The seismic and root-mean-square (RMS) amplitudes deliver insufficient reservoir qualities. The CWT technique detects the low-frequency shadow zone at 37 Hz, which indicates the presence of a gas-bearing zone along the fault. The instantaneous frequency model detects a ∼ 35 m thick sandstone lens encased within the erosional sediments, which was corroborated by a 37 Hz tuning cube. The acoustic impedance-based instantaneous spectral thickness model brightens the high-porosity zones within the thick valley-plugged reservoirs of 40 m and 30 m at 37 Hz and 48 Hz.