Reflection seismic-based imaging of meandering channels of Lower Indus Plain using wavelet transform-based density-porosity hydro-geophysical simulations: Implications on water exploration
Abstract
Water-bearing meandering channel streams (MCS) are very attractive targets for the exploration of fresh drinking water for meeting the demands of human needs. There are various techniques that are used for the exploration and management of water-bearing reservoirs. Seismic reflection data (SRD) is an effective method used in groundwater exploration. SRD is the product of density and velocity information, which are hidden inside this data. The sub-surface layers of the earth’s crust have specific tuning frequency contents, which can be used to predict the exact density, velocity, thicknesses, and porosity of the water-bearing reservoirs. The clean,\r\nsandstone-filled, water-bearing channels have a better quality of water compared to the shale- and clay-filled zones. Therefore, the discrimination of this reservoir facies becomes difficult using the SRD. This study utilizes the seismic reflection method for the exploration of water-bearing zones at depths of 25 to 65 m for a\r\nconfined aquifer inside the Miano area, Lower Indus Platform (LIP), Pakistan. The wavelet-transform-based density-porosity and velocity-porosity hydro-geophysical simulations (WDVHS) are used as a key exploration tools for the quantitative prediction of the water-bearing stratigraphic trap. The full spectrum (bandlimited)\r\nseismic amplitudes do not have the tuning frequency contents, which could be used for the quantitative prediction of the exact density and velocity of the channel stream. The WDVHS has predicted the quantitative attributes of this confined aquifer. The least angle of the sandstone lens’s layer implicates the equilibrium position of the hydraulic head. The water table was present at a depth of 8 m. The clean, water-bearing sandstones have the lowest densities of 1.2, 1.5, and 2 g/c.c. and a porosity of 20 to 30%. Shale-clay-filled impure sediments have a density of 2.3 g/cc and < 10% porosity. The total thickness of this confined aquifer was 29.8 m, which has the least velocity of 554, 1024, and 1494 m/s for clean water-bearing sandstones and 3372 m/s for impurities in shale or clay-filled sediments. This study can be used for drilling exploratory wells for water exploration inside the LIP and world-leading water zones.
Author
Rebwar Nasir Dara
DOI
https://doi.org/10.1016/j.jappgeo.2022.104863
Publisher
Journal of Applied Geophysics
ISSN
0926-9851
Publish Date: