SEDIMENTOLOGY AND HYDRAULIC CONDUCTIVITY OF OUTCROPPING SANDSTONE FACIES OF THE LOKOJA FORMATION AT KOTON-KARFE, SOUTHERN BIDA BASIN, NIGERIA

Abstract

This study investigates the sedimentological characteristics and hydraulic conductivity of sandstone facies of the Lokoja Formation exposed at Koton-Karfe in the Southern Bida Basin, Nigeria. The study aims to evaluate the grain-size distribution, mineral composition, and permeability of the outcropping sandstone in order to assess its reservoir potential. Methods employed include sieve analysis, petrographic examination, and permeability testing. Results from sieve analysis indicate that the sediments are predominantly medium- to coarse-grained, poorly sorted, very positively skewed, and very platykurtic. Petrographic analysis reveals that quartz and feldspar are the dominant minerals, with quartz occurring in the highest proportion. The mineral composition suggests that the sediments were derived mainly from volcanic-plutonic rocks or pre-existing sedimentary sources. The presence of feldspar and poor sorting indicates that the sandstones are both mineralogically and texturally immature. Permeability test results indicate low hydraulic conductivity, suggesting poor reservoir characteristics. These findings give insight into the depositional environment and reservoir quality of the Lokoja Formation sandstones in the study area.