Abstract

Compressional and Shear wave velocities (Vp & Vs) have been measured on dry and brine saturated core plugs of Gollapalli and Mandapetta sandstones under ambient as well as insitu confining pressure conditions. The data generated under confining pressure conditions shows simple linear relationships between Vp and Vs. For dry core plugs, the Vp-Vs curve passes through zero and the ratio Vp/Vs is constant. However, the linear trend for brine saturated core plugs begins at a value of Vp which is slightly less than the velocity of brine and Vs = 0 and thus the ratio Vp/Vs increases as we approach the water point. The relationships of Compressional and Shear wave velocities with porosity show that the velocities decrease with increase in porosity. Based upon these relationships, the matrix velocities Vp & Vs arrived at for Gollapalli and Mandapetta sandstones are 6700m/sec & 3400m/sec and 5950m/sec & 3500m/sec respectively