A core-based XRF scanning workflow for continuous measurement of mineralogical variations in clastic reservoirs

Clastic reservoir core is routinely characterized using conventional, destructive spot sampling techniques. Whilst spot sampling provides useful textural and compositional information, the samples are typically widely spaced (∼ 25 cm), and hence continuous variation in rock composition/texture is not fully captured. It is therefore important to develop higher-resolution rock characterization techniques. In this paper, compositional data from a micro x-ray fluorescence (µXRF) scanner (hereafter Itrax) was used to demonstrate near-continuous (at 200 µm resolution) mineralogical variations in an ancient sandstone core. Traditionally, Itrax was used for compositional profiling of soft sediment cores, with limited use of this technology with rock cores. The acquired XRF data reveal subtle but systematic vertical compositional/textural trends, that may reflect distribution of major sandstone forming mineral grains, clay minerals, diagenetic carbonate cements and identification of new textural subdivisions in sandstones, which would not otherwise be seen with conventional plug analysis, implying the importance of high-resolution core scanning techniques for continuous measurement of mineralogy in clastic reservoirs. • Limited literature could be found whereby the capability of Itrax scanning has been extended to ancient, clastic cores. • Itrax is a non-destructive technique, where elemental composition is obtained directly at the surface of a split core at resolution significantly higher than conventional plug based techniques. • Itrax data acquisition is a quick process (few hours) and mineral distribution trends can be used as guide for further specialized sampling and detailed investigation of clastic reservoirs.