Targeting of high quality groundwater in the province of Vientiane, Laos, PDR

University essay from Luleå/Chemical Engineering and Geosciences

Abstract: Magnetic Resonance Soundings (MRS) has been proven to be an efficient tool
for detecting groundwater in the northern part of Vientiane, Laos PDR. This
is the first time of testing in Laos’s area where the magnitude of earth
magnetic field is higher than 43,700 nT. Testing of MRS here would have the
advantages of high penetration depth and amplitude of MRS signals produced
by the hydrogen proton in the subsurface water layers. Good signals have
been achieved by carefully selecting sites of low background noise (< 1,000
nv), low magnetic susceptibility of subsurface and /or surface soil (< 10-3
si), and small variation of a local earth magnetic field. the mrs results
agree well with the subsurface geological structures and the water
productivity provided by boreholes data in the vicinity of investigated
area. the higher water productivity was found in the area of thicker soft
sediment layer.
schlumberger ves has been conducted in the same target area of groundwater
exploration and their results were also served for mrs inversion. comparison
results of ves and mrs have been made and they are generally consistent. at
the site where a water-bearing layer in the deeper parts is suggested by mrs
with a detection of low signal amplitude and large variation of observed
decay time, the ves result also confirmed that the layer is very high
conductive.
this case-study demonstrates that the mrs and ves methods can be an
effectively selective method for groundwater investigation and can be
integrated with other geophysical methods to fulfill groundwater database in
laos pdr.

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