Lithofacies and Environmental Analysis of Reservoir Sandstones in the “ABOM” Oilfield of Eastern Niger Delta, Nigeria

Abstract

Facies of part of the Coastal swamp depobelt was analyzed using well log. Electrofacies was defined based on well log signatures. The defined facies were inter-related to define a facies association. The facies association were related to deltaic depositional cycles. 10 of such facies association or deltaic cycles were seen in the interval studied. The facies association or deltaic cycles have a different composition of facies related to the level of preservation of the components of the association. The component of the facies association seen include marine clay facies, lower shoreface facies, upper shoreface facies, prograding mouth bar facies and fluvial facies. The marine clay facies underlie each facies association and the channel / prograding mouth bar cap the association where it is preserved. The lower shoreface facies, upper shorefacies, prograding mouth bar and fluvial facies form the Reservoir sandstones. The identified facies association was seen to be repeated in the interval studied though with different composition. This reflects different deltaic depositional cycles with different component of facies due to the prevailing depositional processes occurring at the period of deposition and those affecting the deposit of the cycles after deposition. The arrangements of the different components of the facies within the facies association will help in the prediction of reservoir sand bodies in any deltaic depositional cycle.