Core-Log Integration For A Saudi Arabian Sandstone Reservoir

Abstract

ABSTRACT For a detailed characterization of a reservoir, core-log integration is essential. In this paper, data integration from logs and cores of a Saudi Arabian sandstone reservoir is discussed with particular attention to effects of clay on resistivity logs and water saturation. There are four sources of data, namely, core resistivity measurement, clay study from cores (XRD, CEC), spectral core gamma ray, and well logs. In order to generate continuous cation exchange capacity (CEC) with depth, spectral gamma ray measurements (both from core and downhole log) and CEC from cores are correlated. Qv (CEC per unit pore volume) values are calculated utilizing only well logs by applying Waxman-Smits equation in water bearing zone. Log derived Qv values from water zone were then correlated with porosity to generate Qv values in the oil column and compared with core derived Qv. Finally, data from well logs (porosity, resistivity and qv) and cores (resistivity parameters m, n, and Qv) were integrated for more accurate water saturation calculation. The core-log correlation can be applied to other wells avoiding expensive core analysis, and the technique developed in this project can be used in other sandstone reservoirs.