Reservoir Characterization using Petrophysical Evaluation of W-Field, Onshore Niger Delta

Abstract

Reservoir characterization of W-field, onshore Niger Delta was carried out using petrophysical evaluation of well logs. Three reservoir sand intervals (A, B, C) were identified and correlated across four wells (W1, W2, W3, W4) in W-field using the gamma ray, while the fluid identification of each reservoir was achieved using the resistivity log. The reservoir C interval was selected and utilized for petrophysical interpretation was penetrated at depths 11741-11945ft, 11933-12173ft, 11658-11847ft and 11926-12095ft across all wells respectively.The average values of gross thickness, volume of shale, effective porosity, total porosity, permeability, water saturation and hydrocarbon saturation of the delineated reservoir sand are 200.5ft for gross thickness, 18% for shale volume, 21% for effective porosity, 26% for total porosity, 1071.74mD for permeability, and 28% for water saturation and 77% for hydrocarbon saturation. Petrophysical evaluation revealed that porosity and permeability are very good to excellent in the field. The reservoir is classed as clean sands based on the high net to gross ratio (>70%) and the low shale volumes (<30%). Consequently, the low value of shale volume, low value water saturation, high value of hydrocarbon saturation and the good porosity and permeability properties of the reservoir of interest suggest economical and commercial quality and viability of the wells within this field.

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“…Petrophysical evaluation plays a crucial role in determining various reservoir rock properties such as porosity, shale volume, and water saturation [ [44] , [45] , [46] ]. This process often necessitates the use of dedicated petrophysical software, like Geolog, for proper data management and quality control.…”

“…This method's efficacy is particularly pronounced in the case of unconventional reservoirs, where conventional log interpretation methods might be insufficient [ 44 ]. Once the computations are complete, the results are calibrated against core measurements for validation.…”