부산대학교 도서관

Sedimentary facies, petrographic, textural, and mineral analyses of sections of conglomerates/pebbles and sandstone facies of the Lokoja and Patti Formations in southern Bida Basin, Ajali and Abeokuta Formations in the Anambra and Dahomey Basins in Nigeria respectively were carried out. These analyses aimed at deciphering the paleo-environment and reservoir potential of the formations. The study entailed field observations, petrographic, mineralogical (using X-ray diffractogram), granulometric, and pebbles morphological analyses. The fifteen lithofacies were identified and grouped into three main facies associations. The petrological results revealed that the dominant minerals are quartz, feldspar, and clay. The mineral analysis (XRD) also shows that quartz is predominant; the granulometric result shows that the formations are characterized by poor to well-sorted, strongly coarse to strongly fine skewed, and mesokurtic to leptokurtic sandstone grains. Pebble morphometric indices indicate fluvial to shallow marine fields. The integration of the sedimentary facies and textural analyses is suggestive of the shallow marine subtidal channel, subtidal wave, and estuarine mudflat environments with strong fluvial influences. Based on textural statistical and mineral analyses, the sandstones are moderately matured to immature, and the reservoir quality of sandstone facies is classified as good to very good in Lokoja, Ajali, and Abeokuta Formations and very poor to poor in Patti Formation. The areas that are potential and non-potential hydrocarbon reservoirs have been identified which will be beneficial to petroleum industries.