الفهرس 
AbstractOnly 14 pages are availabe for public view
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Abstract
Generally the geophysical interpretation of resistivity sounding data is to
determine the thickness and resistivity of the different horizons from the quantitative
interpretation of the VES curves. However, the survey data usually are processed after
returning to base camp or laboratory such that the success of each measurement is
determined post-facto and this may have undesirable practical consequences. It would
be more cost effective to assess the success of a sounding on-the spot and modify the
experimental set-up as appropriate. In fact, if the data can be processed at a faster rate
than that of acquisition, then all the analyses can be done in real-time resulting in
considerable savings in time especially in surveys generating large volumes of data. In
addition, the interpretation of resistivity data is limited to the available software
developed only for common electrode arrays. Therefore, it is necessary to develop a
simple and semi-analytical (empirical) method of interpretation that can be applied to
most electrode arrays with high certainty in estimation of depth and true resistivity of
subsurface formations.
In the present study, two simple infield semi- analytical methods (cumulative
and inverse slop method) were applied to the interpretation of VES’es measured with
different electrode arrays in two and three layers laboratory tank model (consist of
well graded gravel, sand and silty clay of know thickness and resistivity) and field
survey at different localities. The study showed that the cumulative resistivity method
is a quick method for obtaining depths to interfaces; however the inverse slope
method (extension to cumulative resistivity method) can be used to determine the
absolute resistivities. These methods can be implemented on a hand-held calculator or
more efficiently on a small microcomputer where the data can be processed at a faster
rate than that of conventional data acquisition systems. This allows the methods to be
potent tools for infield data analysis and more cost effective to assess the success of a
sounding on-the spot and modify the experimental set-up as appropriate.
Finally, the comparison between the results obtained from the semi-analytical
methods and the computerized techniqes indicated that the geoelectrical models
derived from the semi-analytical methods have a good correlation with the actual
models. Also, the proposed methods gave a good result when applied on VES’es
measured by using Schlumberger and Wenner arrays collected from different areas of
different geologic setting, where the results are in confortable with the actual lithologyIII
obtained from the lithologic data of the neighbouring wells. from these results
obtained from laboratory tank and feild survey at different localities indicated that the
semi-analytical methods have the potential to be applied to VES data collected with
any electrode array, the advantage that is not available with all the computerizedinterpretation programs available nowadays.