MODELLING OF SOIL RESISTIVITY, DRILL DEPTH AND OVERBURDEN THICKNESS IN PREDICTION AND VALIDATION OF SINKING PRODUCTIVE BOREHOLE

Abstract

ABSTRACT Portable water scarcity has constituted a big challenge in Ogbomoso city as a result of increase in population of inhabitants and abandonment of public water supply on the part of government. In view of this, general public have resolved to find alternative means of drilling boreholes to cater for their needs. This study developed models taking into consideration factors that are vital in prospecting for underground water such as borehole depth, overburden thickness and soil resistivity among others. Existing data from 104boreholes were gathered and the aforementioned three parameters from existing wells were modeled to estimate depth and lithological thickness once resistivity is known. The two equations (models) can be used especially to estimate borehole depth and validate it, in and around the study area of Ogbomoso. Statistical was used in the analysis of data pooled from all the wells visited and the result obtained showed that both borehole depths and soil resistivity are moderately correlated with correlation coefficient of 0.31. In the study area, two models were developed, same was tested and it was established to be okay though with minimal error, it is recommended that the models should be used after survey work has been carried out and correlate model results with that of geophysical survey carried out by the geologist.

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