On May 11th 2007 the following set of logging tools were run in well XXII in the Middle East:

Induction / Micro Resistivity/ GR
Image Log
3D Induction Log
Spectra Log
Sound log
Density/ Neutron

The Open Hole Set:
The main logging tools ( Density/Neutron, and Induction/Micro-Resistivity/GR) were run as per normal practice in
the open hole section and across the reservoir interval.  The Induction Logging tool acquire the resistivity of the formation
and is insensitive to the sequences of low – high resistivity beds within the reservoir.  Therefore, the data from Induction
will read rather “horizontal “ resistivity that will be affected by the presence of high capillary formation water across the low resistivity pay and is also insensitive to the layering.  Therefore, the 3D new resistivity tool was suggested to run that is now provided by the major service companies.
3D Induction - Image Tools:
It was suggested that the 3DInduction Logging tool should be run for the following reasons:
This tool is capable of delivering the anisotropy across the sub reservoirs R1, R2 and R3 if any.
3D Induction can quantify the low resistivity pay intervals.  The accurate vertical and horizontal resistivities are
measured in order to find out any differences that would reflect the real resistivity of the pay zone across the
Differentiates the productive from the unproductive zones across the low resistivity pay zone.  This can be
modeled in both; Carbonate and Sand Stone reservoirs.
Quantify the extra oil in place based on the “real” formation resistivity across the sequence bed zones.
Identifies formation dip and azimuth.
What is Anisotropy ?

Anisotropy means predictable variation of a property of a material with the direction in which it is measured, which can
occur at all scales. For a crystal of a mineral, variation in physical properties observed in different directions is anisotropy.
In rocks, variation in seismic velocity measured parallel or perpendicular to bedding surfaces is a form of anisotropy.
(Compare with homogeneity.)

The figure below depicts the definition of anisotropy;


The figure below depicts the definition of anisotropy;


Anisotropy and isotropy can depend on scale. While a single crystal can be anisotropic, many crystals together can
form an isotropic or homogeneous layer within an otherwise anisotropic rock.

The property of being anisotropic means having a different value when measured in different directions.

In physics, anisotropy means the quality of exhibiting properties with different values when measured along axes in
different directions. Anisotropy is most easily observed in single crystals of solid elements or compounds, in which atoms,
ions, or molecules are arranged in regular lattices. In contrast, the random distribution of particles in liquids, and
especially in gases.


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