Investigation of Sandstones Wetting by X-ray Microtomography

Abstract

X‐ray microtomography is a non‐destructive imaging technique. It consists in cross‐sections object reconstruction based in the linear attenuation coefficient maps achieved through the object illuminating by a X‐ray beam at different angular positions. It has been used by various researches to supply microstructural informations of materials as ceramic filters, pills, titanium prosthesis and reservoir rocks. An item of great interest has been the characterization of the liquid phase presence in porous space. This paper shows the X‐ray microtomography methodology employed to achieve qualitative and quantitative results about Botucatu sandstones wetting. It was used a Skyscan, 1172 model, which employs an X‐ray tube with W anode and a cone beam. This laboratory based equipment is able to provide images of until 1 μm spatial resolution. The employed samples were two cores of layered Botucatu sandstone, named ARN1 and ARN 2. These samples were scanned in two situations each one, dried and wet. 2D images, porosity values for each 2D image, total average porosity and pose size distribution for the dried and wet situation were compared. H20‐NaCl‐KI solution was employed for the samples wetting procedure. The two samples were scanned with 4.84 μm spatial resolution. The total average porosities obtained for ARN1 sample before and after wetting were 4.4±0.7% and 1.8±0.4%, respectively.