Using Electrical Wireline Logs For Aquifer Characterization In Parts Of Anambra Basin, Southeastern Nigeria
Interpretation by use of quantitative methods of electric log dataset was successfully applied to sandstone aquifers in parts of Anambra Basin of Nigeria. Depth to aquifers varies between 67 and 213m above mean sea level, porosity ranges between 13 and 55%. Transverse (unit) resistance T changes between 0.037 and 6.80 ohm-m2. Specific Conductance ranges between 312 and 794 micromhos/cm, Transmissivity varies between 0.54 and 3.36 m2/s while Total dissolved solids varies between 4.16 to 176.89 ppm.
Variation in borehole elevations above sea level showed that the aquifers are not at the same surface in most part of the basin but undulating. This variation in aquifer heads is assumed to have key controls in underground water divide and direction of water flow within the basin. There was also evidence that variations in porosity are directly related to lithofacies and grain size.
Keywords: Electrical logs, Resistivity, Formation factor, aquifer parameter, Anambra Basin
Global Journal of Geological Sciences Vol. 6 (1) 2008: pp. 33-40