Determination of The Hydraulic Conductivity, Transmissivity And The Environment of Deposition of Owelli Sandstone, in Anambra Basin, Southeastern Nigeria, Using Grain Size Distribution Analysis

Abstract

This study estimated hydraulic conductivity, transmissivity, and interpreted the environment of deposition of the Owelli Sandstone in Mbanabor area of Anambra Basin, Southeastern Nigeria. These were achieved using grain size distribution analysis, and borehole lithological logs. The results indicated that values of hydraulic conductivity (m/s) and transmissivity (m²/s) range between 2.89 x 10^-2 – 1.52 x 10^-1, and 4.8 x 10^-1 - 5.3 x10^-1, respectively, indicating prevalence of aquifer of good performance. The aquifer units are predominantly unconfined, with variable thicknesses and depth of occurrence. The values of the mean, sorting, skewness and kurtosis, from sieve data range between 0.2 - 0.9Φ, 0.49 - 1.97Φ, -0.05 - 0.21Φ and 0.96 - 1.52Φ respectively. Multivariate discriminate functions revealed that Owelli Sandstone may have been deposited dominantly by beach process, in shallow agitated marine, and shallow marine environment.

Key words: Hydraulic Conductivity, Transmissivity, Owelli Sandstone, Anambra Basin, Depositional Environment.