Petrophysical Evaluation of Flow units of the Agbada-Akata Formations in the Niger Delta

Abstract

Clastic reservoirs may be heterogeneous and exhibit lateral and vertical variations in porosity and permeability. Therefore, the spatial distribution of the petrophysical properties within the reservoirs is important to provide a reliable reservoir description. An improved understanding of clastic reservoirs has led to more detailed reservoir description by flow unit delineation. In this study, six active wells which cut across zone D3000 in the Tertiary Niger Delta clastic reservoir were used for the petrophysical analysis. The study tests the applicability of the RQI method as a tool for identifying and characterizing reservoir flow units in the Agbada-Akata formations. Gamma ray log, caliper log, density log and core data from the offshore Tertiary Niger Delta field were used in the petrophysical evaluation of the flow units. Based on the petrophysical data generated, the characteristics, variability and distribution patterns of porosity, permeability and facies within the flow zones were analyzed for the reservoir sands of the formations. The properties (porosity, permeability, and facies) were distributed stochastically within a 3D grid using Sequential Gaussian Simulation, Sequential Gaussian Cosimulation, Sequential Indicator Simulation and Kriging Algorithms to describe the flow characteristics of the study reservoir. This study has demonstrated the effectiveness of the RQI method coupled with 3D geostatistical modeling technique, as a tool for better understanding the spatial distribution of continuous and discrete reservoir properties, hence it has provided the framework for the future prediction of performance and production behavior of the Agbada-Akata petroleum system.