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Knowledge of reservoir evaluation is helpful in the
interpretation of well-logging data, where the hydrocarbon
saturation is expected as the final result by Archie
equation. It is calculated from the deep resistivity, water
formation resistivity and porosity. Porosity is calculated
from the bulk density, neutron and sonic are measured
directly in the well. The Archie evaluation, in the low
resistivity layers, is characterized by high water
saturation. The MDT tests in the low resistivity pay prove
several oil samples. For this incompatibility interpretation
of low-resistivity-contrast pay zones needs an analysis of
the reservoir composition in the study area. The divergence
results between Archie and well test allow integrating a new
evaluation approach. However, the proposed interpretation
framework does allow the incorporation of new logging
technology as this becomes established. Nuclear magnetic
resonance (NMR) is a useful tool in reservoir evaluation.
The objective of this study is to predict petrophysical
properties from NMR T2 distributions. The evaluation of NMR
relaxation time distributions estimates of pore-size
distributions. Irreducible water-saturation estimates from
NMR-based pore-size distributions. In this study, we look at
the down hole NMR measurements to determine pore geometry
and volumetrics within a reservoir (free fluid index). NMR
measures the net magnetization of a hydrogen atom (H) in the
presence of an external magnetic field. Hydrogen has a
relatively large magnetic moment and is abundant in both the
water and hydrocarbons that exist in the pore space of
sedimentary rocks. NMR measurements provide information
about the pore structure (Sp), the amount of fluid in situ
(FFI), interactions between the pore fluids, and surface of
pores and provide important information for evaluation of
low-resistivity layers.
Keywords:
reservoir
evaluation, well-logging data, hydrocarbon saturation,
Archie equation. MDT tests, Nuclear magnetic resonance
(NMR).
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