A systematic experimental study of different synthetic, outcrop and reservoir rock samples has been carried out to investigate the effect of clay minerals, pressure and temperature on the estimation of in situ rock volumetric parameters from electric logs. This paper outlines the key experimental results and indicates areas for improvement in the determination of hydrocarbon volume in place using the Archie equations for clean sands or a new conductivity model for shaly sands. The following factors have been considered in this study: the effect of pressure, temperature and hysteresis on formation factor and cementation factor, and the influence of temperature and clay distribution on the excess conductivity of the electric double layer associated with clay minerals.

Keywords:
porosity, saturation, resistivity, upstream oil & gas, shaly sand conductivity, reservoir, clay mineral, cementation factor, equation, formation factor
Subjects:
Formation Evaluation & Management, Open hole/cased hole log analysis
Copyright 1991, Society of Petroleum Engineers
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