Análise Microestrutural de Arenito da Formação Rio do Rasto pela Microtomografia Computadorizada por raios X

Abstract

In this paper, microtomographic images of Rio do Rasto formation’s sandstone are analyzed, obtained by X Ray Micro Computed Tomography methodology. They were were performed with SkyScan 1172 microCI scanner and, some physics properties were obtained, such as: porosity (closed and connected), pore size distribution, REV (Representative Elementary Volume), and 3D reconstruction. This is a nondestructive method and it provides internal information about rocks without destroying them, it’s strongly used by petroleum industries. About image acquisition, the spatial resolution was 5.87 micrometer and the X-ray tube voltage was adjusted to 70 kV. Then, the projections were reconstructed – generating 2D sections – and artifacts were reduced at tomographic images. With Imago and CTAn softwares, physics parameters were analyzed on the Region Of Interest (ROI). When the standard threshold (67) was applied on the 8 bits color scale, we obtained – through Imago software – 13,54(66) % of total porosity, where 12,58(74) % is related to connected pores. Considering the percentage of connected pores and the pore size distribution, it infers that this sample might show a reasonable permeability. VER was reached with a 2,900 mm cube’s edge. Comparing with previous works, it noticed that this rock has a great level of variability.