Research on the Interface Structure during Unidirectional Corrosion for Oil-Well Cement in H₂S Based on Computed Tomography Technology

Abstract

The disruption of interface layer occurring in cement stones during corrosion was investigated using three-dimensional (3D) X-ray computed tomography (CT). This study was conducted using this characterization technique by continuously examining the air-void within a sample. Examination of the obtained CT images shows that air-void distribution of the interface layer of the cement stone exposed in humid H2S gas exhibits a clear difference from the distributions found in unexposed samples. To confirm this difference, a dense layer was found using scanning electron microscopy, which was in good agreement with the CT image analysis showing that the air-void of the dense layer was much smaller than that in the unexposed sample. The compositions of the interface layer were further investigated using several characterization techniques such as scanning electron microscopy (SEM), SEM-energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD).