Azimuthal resistivity survey for anisotropy studying.
The first aim of resistivity survey is a study of any inhomogeneities.
Frequently in practice the effect of anisotropy is displayed together with
that of layering or inhomogeneities. 
It
complicates data interpretation within the framework of anisotropic models,
and distorts results of interpretation in the framework of layered or inhomogeneous
media. Ignoring of anisotropy results in wrong data interpretation. At
the same time anisotropy studying can give valuable geological information.
That means that anisotropy itself and the mutual influence of anisotropy
and inhomogeneities needs to be studied. On definition, rock anisotropy
is displayed in apparent resistivity values as dependence on array orientation
and as independence on coordinates. Azimuthal (or circular) resistivity
survey (ARS) is the best field technology for anisotropy studying.
There are several problems of anisotropy which were considered in this
study.
0. Origin of resistivity anisotropy in rocks.
1. Choice of array, which is more sensitive
to anisotropy.
2. Type of array rotation to find the difference
between anisotropy and inhomogeneity influence.
3. Visualization of azimuthal resistivity survey
(ARS) data.
4. Data processing and interpretation.
5. Signs of anisotropy and that of inhomogeneity
in spectra of ARS data.
6. Anisotropic and pseudo-anisotropic models.
7. Forward problem calculation for different
anisotropic models.
8. Field ARS measurements in areas with high
and low anisotropy.
9. Software for anisotropy modeling and interpretation.
10. References.
119899, Russia, Moscow, Moscow State University, Geological Faculty,
Department of Geophysics.
V.A. Shevnin, I.N.Modin
Tel. & fax: (7-095) 939 49 63
E-mail: sh@geophys.geol.msu.ru
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your comments.