Centre Universitaire de Recherche et d’Application en Télédétection (CURAT), UFR des Sciences de la Terre et des Ressources Minières, Université Félix Houphouet-Boigny, Abidjan, Côte d’Ivoire
In the present work, the cement and/or matrix, pores, and grains present in sandstones were quantified by tele-petrography. The selected sandstones come from the superficial formations of Ivorian onshore basin and the deep formations of offshore basin. A total of six sandstones, three from each part of Ivorian basin, were analyzed. The tele-petrographic analysis consisted of processing the images of these sandstones taken under the natural light from petrographic microscope to the R software using the «terra» package. The results show that the quantification of sandstone components depends on the magnification of the microscope image, the grain size, and the sorting. At low and medium magnifications, a small number of images per rock is sufficient to evaluate the proportions of the components. At high magnifications, however, a large number of images are required as they tend to overestimate the proportions of grains at the expense of other components (porosity, cement, matrix) if the grains have a poorly sorted. The presence of phenocrysts accentuates these variations. However, if the sandstones have a well sorting, the proportions of components hardly vary from one image to another, whatever the magnification. The density curves and histograms reveal that the number of components on these curves depends on the proportions; the higher the proportion of a component the better it is represented. Low proportions remain invisible on the density curves. Remote sensing is therefore promising for the evaluation of the petrophysical properties of reservoir rocks.