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Description of
Productive Intervals Using Shear 
Wave
Velocity in
Mohammadnia, Mohammad, Ali Mohammad Bagheri, Research Institute of Petroleum Industry (RIPI),
The analysis of shear wave velocity and its relationship with
reservoir properties provides an opportunity to include a detail investigation
of reservoir rock and patterns of flow behavior. Sonic travel time of compressional wave is generally used as porosity tool for
given lithology. Introducing shear wave travel time
is very helpful in determining mechanical rock properties and fluid type. In
many developed oil fields, only compressional wave
velocity may be available through old sonic logs or seismic velocity check
shots. Therefore estimation of shear wave velocity in reservoir
characterization is essential.
In this paper for the 40 core plugs taken from 4 wells in sarvak and gadvan formations
porosity, and permeability, compressional and shear
wave velocities were measured. Elastic wave velocity measurement conducted in
both dry and saturated samples under reservoir condition. Experimental and
artificial intelligence technique such as fuzzy logic and neural networks were
employed to estimate shear wave velocity using log data.
A new statistical methodology was also developed for shear wave
velocity estimation based on core measurements, and wire-line log data from 4 wells,
then results of this method and previous method were compared with shear wave
velocity has been obtained from dipole sonic log in an other well that it was
show good correlations. The velocity ratio (Vp/Vs)
was then used as a physical basis to direct hydrocarbon detection and fluid
delineation and behavior of acoustic waves in productive intervals was
studied.