Description of Productive Intervals Using Shear Wave Velocity in Southwest Iran

Mohammadnia, Mohammad, Ali Mohammad Bagheri, Research Institute of Petroleum Industry (RIPI), Tehran, Iran

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.