Authors :
Badrinarayanan T.S; S. Sundaramoorthy; Dr. N. Jawahar Raj
Volume/Issue :
Volume 7 - 2022, Issue 9 - September
Google Scholar :
https://bit.ly/3IIfn9N
Scribd :
https://bit.ly/3U8s3h0
DOI :
https://doi.org/10.5281/zenodo.7080473
Abstract :
While the presence or absence of water in the
subsurface obviously should have an effect on the
electrical properties of the ground, in the exploration
process, particularly in relatively unexplored basins, it is
not always immediately clear whether groundwater is a
low resistivity target relative to background, or a high
resistivity target. Correlation with known or suspected
geological structure, borehole geophysics, and down-hole
lithology is often critical in the proper application of
surface geophysics to groundwater exploration. Magneto
telluric [MT] is an electromagnetic surface geophysical
exploration method, can give a good result with good
resolution of data. The constant source audio magneto
telluric method [CSAMT] and natural source audio
magneto telluric method [NSAMT] which are one among
electromagnetic techniques, usually provide better lateral
high resolution at shallow and deeper depths than
galvanic electrical resistivity methods. This research
paper deals with integration of NSAMT- 2D AMT method
and subsurface geoelectric exploration- borehole
geophysics technique to explore the very deep fresh water
aquifer in a saline sedimentary environment for irrigation
needs. The research area falls in Vridhachalam taluk &
block in Cuddalore district of Tamilnadu, South india.
The investigation constraints being complex geological
and hydrogeological setup with salinity problem. Added
to this a very huge thickness of aquiclude and the aquifers
occur @ very deeper depths for which a high financial
investment is needed. The problems were overcome by
carrying out systematic hydrogeological, geophysicalboth electromagnetic and geoelectric explorations and the
very deep freshwater confined aquifer could be
prospected. A pilot borehole to a depth of 312mbgl was
drilled by rotary rig and the borehole was electrically
logged. A tube well of 150mm dia was constructed to a
depth of 312m, developed and finally completed. The
discharge of well is 600 lpm with good potable water
which could cater the water needs of entire farm.
Keywords :
Aquiclude; Confined Aquifer; 2D AMT; Electrical Well Logging; Well Developing
While the presence or absence of water in the
subsurface obviously should have an effect on the
electrical properties of the ground, in the exploration
process, particularly in relatively unexplored basins, it is
not always immediately clear whether groundwater is a
low resistivity target relative to background, or a high
resistivity target. Correlation with known or suspected
geological structure, borehole geophysics, and down-hole
lithology is often critical in the proper application of
surface geophysics to groundwater exploration. Magneto
telluric [MT] is an electromagnetic surface geophysical
exploration method, can give a good result with good
resolution of data. The constant source audio magneto
telluric method [CSAMT] and natural source audio
magneto telluric method [NSAMT] which are one among
electromagnetic techniques, usually provide better lateral
high resolution at shallow and deeper depths than
galvanic electrical resistivity methods. This research
paper deals with integration of NSAMT- 2D AMT method
and subsurface geoelectric exploration- borehole
geophysics technique to explore the very deep fresh water
aquifer in a saline sedimentary environment for irrigation
needs. The research area falls in Vridhachalam taluk &
block in Cuddalore district of Tamilnadu, South india.
The investigation constraints being complex geological
and hydrogeological setup with salinity problem. Added
to this a very huge thickness of aquiclude and the aquifers
occur @ very deeper depths for which a high financial
investment is needed. The problems were overcome by
carrying out systematic hydrogeological, geophysicalboth electromagnetic and geoelectric explorations and the
very deep freshwater confined aquifer could be
prospected. A pilot borehole to a depth of 312mbgl was
drilled by rotary rig and the borehole was electrically
logged. A tube well of 150mm dia was constructed to a
depth of 312m, developed and finally completed. The
discharge of well is 600 lpm with good potable water
which could cater the water needs of entire farm.
Keywords :
Aquiclude; Confined Aquifer; 2D AMT; Electrical Well Logging; Well Developing
