INVESTIGATING ELECTRICAL RESPONSE TO WATER SATURATION OF AGBADA SANDSTONE IN AN X-FIELD NIGER DELTA, NIGERIA

Kelvins Ugbena,Cyril Nwankwo,Aurelius Omali

doi:10.35180/gse-2019-0015

Kelvins Ugbena, Cyril Nwankwo + Show 1 more

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https://doi.org/10.35180/gse-2019-0015

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Abstract

In an attempt to characterize a reservoir in a field, importance is given to living models as it serves critical function in estimating if the reservoir under study is economically viable. Having a good knowledge of electrical response to reservoir rocks is important in characterizing and modeling the behavior of fluids at the subsurface. In this study, core plugs extracted from core barrels in a Niger Delta oil field were analyzed in the laboratory in order to determine the electrical properties of the samples and their relationship with each other and formation fluid. This was achieved by using a brine of a known concentration for simulation of core plugs. Results obtained show that for the unconsolidated sandstone, Formation resistivity factor increases with an increase in confining pressure. This characteristic depends on the porosity of the Formation and type of fluid present. Resistivity values in a reservoir will increase with an increase in capillary pressure and decrease with water saturation. The decrease in cementation exponent increases the rate of permeability in reservoir sand. However, resistivity values decrease with clay presence in reservoir sand.Keywords: Core plug, reservoir, resistivity, water saturation DOI 10.35180/gse-2019-0015

Highlights

Once an exploration well has been drilled, the “living model” begins to serve more critical function, determining whether or not the well is a commercial success and defining the initial characterization of the reservoir
As observed from the results of the various plugs (Tables 2-7), Formation resistivity factor increases with an increase in confining pressure from 500-2900 psi; for all plugs as fluid content is lost due to increasing pressure
Formation factor is a fundamental measurement for reservoirs fluid saturation, which is a function of porosity, type of fluid and type of rock

Summary

Introduction

Once an exploration well has been drilled, the “living model” begins to serve more critical function, determining whether or not the well is a commercial success and defining the initial characterization of the reservoir. Model studies in geophysics have become a very important tool in the interpretation of geophysical and electrical data. Electrical modelling studies involve the generation of electrical response over regular objects which are buried in a medium with contrasting physical properties. The use of models in electrical method of exploration such as electrical resistivity is a useful aid in the interpretation of electrical responses within a medium in different fields [1]. For a critical reservoir parameter determination, it is best to characterize the property of a rock type. The rising interest in understanding some basic properties of reservoir rocks such as electrical properties has led to the extraction of more data from the earth subsurface [3]

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