Estimation of acoustic wave velocities in miocene reservoir rocks based on theoretical model

Seismic interpretation applications, especially AVO analysis and bright spot analysis, require knowledge of the distribution of P-wave and S-wave velocities with depth. This is of particular importance in gas-bearing zones. Elastic wave velocities in hydrocarbon-saturated rocks (especially gas-saturated) are different than those observed in water-saturated rocks. Seismic survey, acoustic full wavetrain logs, and laboratory tests verify this. Based on the Kuster and Toksöz’s relations (1974, Toksöz at al.,1976), which were modified by the author of this paper (Bała, 1989, 1994, 1997), P-wave and S-wave velocities and corresponding acoustic impedances, ZP and ZS, were calculated as functions of different mineral composition, matrix parameters and porosity of rocks from selected Miocene horizons from borehole P-6.