Hello friends of steemit. In this opportunity I show you the effects of the anisotropy of the subsoil in the process of seismic interpretation.
Many mathematical models used in seismic exploration suppose idealized or isotropic means which lead in some study areas due to their complexity, to an erroneous interpretation of the subsoil.
This release includes and analyzes the impact of anisotropy on velocity and elastic impedance maps of the subsoil discussed in the first part (Geophysics - Exploration method (Elastic Impedance)) where the models used represent isotropic means.
A medium is called anisotropic with respect to a parameter if its value changes with the direction of measurement (Figure 1).
Figure 1 Source
Thomsen (1986), using velocity functions, defines the anisotropy parameters that control the propagation modes of the P wave (primary), S wave (secondary)
Later Brittan in (1995) derived the parameters of Thomsen Vp, Vs, δ, ε in terms of the elastic properties of the constituent strata of the soil.
where:
The delta parameter dominates the anisotropic response in the horizontal
The epsilon parameter dominates the anisotropic response in La vertical
Elastic modules in function of Velocities Vp and Vs
ρ1 and ρ2 are the respective densities of the two strata, Φ is the fraction of material 1 present in the set of constituent strata, 
the average velocities between the strata and the terms 
represent the square of the slowness of the P wave and the square of the slowness of the S wave in each stratum respectively and are defined as:
Speed depending on the Anisotropy
Thomsem (1986)
Elastic Impedance in function of Anisotropia
Lorenzo Rivero (2015)
These expressions of speed and elasticity impedance generalized by Thomsen (1986) and Lorenzo Rivero (2015) in terms of anisotropy, are used for the construction of new maps of the subsoil in which the anomalies that the isotropic model doesn`t show with greater precision are visualized (Figure 2, 3, 4, 5).
Figure 2 - Speed section of the isotropic model in direction A- B
Figure 3 - Speed section of the anisotropic model in direction A- B
Figure 4 - Section of elastic impedance of the isotropic model in the direction A-B
Figure 5 - Section of elastic impedance of the anisotropic model in direction A-B
There are significant differences between the isotropic and the anisotropic model. Anisotropic models show changes in speed and elastic impedance associated with structural and lithological changes that are not visible in the isotropic models.
The incorporation of the anisotropy in the creation of sections of speed and elastic impedance allows identifying potential areas in which future recordings and perforations are aimed, minimizing and optimizing in this way the processes of the required information and calibrating in turn other existing records. the area.
This also allows a significant reduction in effort and costs, in the task of obtaining a reliable seismic interpretation of the study area.
References
Connolly P., (1999) Elastic impedance, The Leading Edge, Vol 18, No. 4438-452.
John Brittan, Mike Warner, Gerhard Pratt. Anisotropic parameters of layered media in terms of composite elastic properties. Geophysics Vol 60. Julio 1995.
Leon Thomsen. Weak elastic anisotropy. Geophysics vol 51.Octubre 1986.
Lorenzo Rivero. Uso de velocidades sísmicas en la programación de registros sonicos de pozos. Julio 1997.
Lorenzo Rivero. (2015) Generalización De La Impedancia Elástica En Un Medio Transversalmente Isotrópico. Trabajo de ascenso. Facultad Experimental De Ciencias Universidad del Zulia, Maracaibo, Venezuela.
I hope that this publication has given you knowledge about the subject. If you have any questions, please leave your comment and then I will gladly try to clarify them.
Thanks for reading my publication.
the average velocities between the strata and the terms 
represent the square of the slowness of the P wave and the square of the slowness of the S wave in each stratum respectively and are defined as:
Excellent post my friend @lorenzor. Regards!