Reservoir Study Analysis Using Petrophysical Properties of Reservoir Rocks of an Offshore Field in Niger Delta Basin

Abstract

A qualitative and quantitative reservoir study of an offshore field (BAK field), was carried out using the analyses of the petrophysical properties of the reservoir rocks in the field for proper planning and optimum production development of the field. Five wells data from the field were utilized for the study and from the analyses of these wells, three reservoir intervals were identified through quantitative interpretation, while reservoir correlation was performed to identify the lithostratigraphic sand unit within the well formations, with the top and base markers distinguishing the respective reservoirs mapped within the wells, the sand bodies of the reservoirs were found to be heterogeneous and continuous. The three reservoir intervals identified were named: BAK_1, BAK_2, and BAK_3 reservoirs respectively, the reservoir sedimentology revealed that the reservoirs were predominantly sands with intercalated shale within the formations. The results of petrophysical analysis revealed that the Net-to-Gross (N/G) values within the identified reservoir were 83%, 86%, and 85% for BAK_1, BAK_2, and BAK_3 reservoirs respectively, while the total porosity and effective porosity were found to be 28%, 27%, 28% and 24%, 24%,18% for BAK_1, BAK_2 and BAK_3 respectively. The permeability values were found to 2279.558 mD, 2178.738 mD, and 2760.678 mD while the water saturation estimated was 45%, 48%, and 48% for BAK_1, BAK_2, and BAK_3 reservoirs respectively. From the results of reservoir study of petrophysical properties, the reservoir can be said to have a low shale volume, excellent porosity, high permeability and low average water saturation. The field can thus be classified as a good candidate for development and optimum production of hydrocarbon.