Flood Plain and Channel Sand Reservoir in Deepwater Environment - A Case Study of ‘Oyo-Dw’ Field Niger Delta, Nigeria

Abstract

The Deepwater environment of the Niger Delta Basin is one of the hydrocarbon exploration frontiers believed to be promising and highly prolific if properly harnessed. Some of the reservoir units are affected by multi-scale compartmentalization resulting from structural, stratigraphic and/or diagenetic processes. Reservoir compartmentalization can compromise the lateral and vertical connectivity of other micro reservoirs thus having significant impact on the estimation of oil-in place and / or recoverable reserves, as well as the placement of exploration development and production wells. “OYO 10” was drilled within the northwest part of the field, all reservoir levels predicted using Amplitude as Direct Hydrocarbon Indicator analysis draped on structural maps. Disappointedly, all reservoir levels show poor sand development with poor hydrocarbon columns. A 3D seismic dataset and geological data from Oil Mining License 121 in the Deep-water environment of Niger Delta was analyzed to assess and quantify the architectural elements that influence the compartmentalization of delineated reservoir units. The key aim of this study was to delineate the reservoir sands in deepwater environmental Niger Delta as it is applicable to channel reservoirs and flood plain. This study involved calibration of seismic-to-well tie, determination of spatial distribution patterns of submarine channels; establishment of hydrocarbon control; evaluation of the reservoir compartmentalization and trapping mechanism over the prospect area. It is important to understand the spatial distribution of Submarine channels because they are made up of important potential reservoir strata. Large channels with numerous smaller channels are laterally scattered across the study area. Attribute analysis revealed the degree of compartmentalisation within the sub-channel and the sand development pattern within the channels and the floodplain. Variance attributes reveal that previous producing wells drilled within the study area were all located within the channel compartments which are also made of micro channels. The results of this study can provide significant contributions to further hydrocarbon exploration in the deep-water area of Niger Delta and hence lead to more discovery and increase in the crude oil reserve.