Abstract

Petrophysics transforms well log measurements into reservoir properties i.e. porosity, saturation, permeability, mineral component volumes etc. Rock-physics transform petrophysical results into elastic properties that can be used for seismic interpretation. This complementary nature of Petrophysics and Rock physics requires a tight integration for seismic reservoir characterization. Well log data plays a crucial role in this process of integration. During drilling process log data are affected by borehole rugosity, invasion, mud cake formation, salinity, temperature & pressure etc. and even some times logs could be entirely missing or not usable due to bad hole conditions. In general, most of the times petrophysical evaluation, petro - elastic modeling and synthetic to seismic tie are done separately prior to integration. This approach increases uncertainty and inconsistency across the geoscientific data. Ideally, Petrophysics and Rock physics modeling should be an integrated process that can produce a greater consistency between all the data and lead to reduced uncertainty. This paper highlights various issues pertaining to log conditioning, synthetic curve generation, petrophysical evaluation results for rock physics modeling and the various scenarios of fluid effects on rock properties as applied in the study of a gas field in Cauvery basin of ONGC, India.