Evaluation of Petrophysical Properties of a Reservoir in Kolo Creek Field, Niger Delta, Using Well Log Analysis.

Abstract

The main petrophysical parameters needed for the evaluation of a reservoir are porosity, permeability, hydrocarbon saturation, thickness and area. Other parameters such as the reservoir geometry, formation temperature & pressure and Lithology, can play vital roles in the evaluation, completion and production of the reservoir. In the study area which is within the Kolo Creek field in the Niger Delta, the method adopted for the evaluation utilized gamma ray logs to differentiate potentially porous and permeable reservoir rock (sands, sandstones and siltstones) from non-permeable clays and shales. Also, neutron and density log combination, were used principally to delineate porous formations, determine the porosity as well as differentiate gas and oil zones. Resistivity logs were used to assess water and hydrocarbon saturations. The quantitative analytical data show average porosity values in the three wells (X, Y and Z) as 16.44%, 16.38% and 17.48%, respectively. Also observable results indicate that wells X, and Z have high hydrocarbon saturation values of 70.18%, 81.46 % and 78.38%, respectively and average water saturation values of 38.27%, 18.55% and 21.62%, respectively. The three wells (X, Y, and Z) have good average permeability values of 326.58md, 274.85md and 310.38Md, respectively. Directly deriving from their petrophysical attributes, it may be inferred that the hydrocarbon producibility of the three wells are of commercial value.