Influence of primary composition and diagenetic mineralization on natural gamma-ray and density logs of Carboniferous sandstones of the Dęblin Formation

The Carboniferous sandstone of the Dęblin Formation is one of the targets for the petroleum industry in the Lublin Basin in southeastern Poland. The formation’s primary and diagenetic composition makes it difficult to estimate its reservoir properties. Based on a detailed analysis of core and petrographic samples, normalization of gamma-ray and density logs was made with respect to the grain-framework of the rock. Recounted logs were used for distinguishing 4 different sandstone petrofacies. For these petrofacies, ranges of gamma-ray and bulk density values were determined and the impact of primary and diagenetic mineral composition was estimated. The application of this petrofacies method can upgrade the level of reservoir characterization and support the interpretation of uncored intervals.