A review of stratigraphic surfaces generated from multiple electrical sounding and profiling

摘要

In this work, we investigate the accuracy of stratigraphic surfaces derived from multiple electrical sounding and traversing. Eight (8) VES stations with AB/2 of > 80 m each and three (3) Wenner profiling of > 120 m each were used for this investigation. The three principal surfaces interpreted include conglomeratic sand (top layer}, sandstone (presumably compacted) and clayey sandstone. These rocks are correlated to the Ise Formation of eastern Dahomey Basin. Our result shows that widely-spaced VES are error-prone and may result in misinterpretation of subsurface resistivity and rock boundaries. Smaller spacing between VES stations can effectively detect minute resistivity anomalies. On the other hand, the inversion method used for interpretation of profiling data can influence the final resistivity values. We propose the criteria for generating strati-graphic surfaces to include (a) adequate geological mapping (b) small electrode spacing for profiling (c) closely-spaced VES stations and profiling lines (d) interpolation of thickness and resistivity in multiple direction and (e) the use of drill hole logs to tie VES models.