Structural and morphological evaluation of three types of carbonate hydrocarbon-bearing rocks from Tampico-Misantla basin: Structural effects after CO₂ injection

The analysis of organic compounds within a rock allows understanding its potential to transform into hydrocarbons. This study employs characterization techniques, primarily spectroscopic methods such as Fourier Transform Infrared (FT-IR) and Ultraviolet–visible (UV–vis) spectroscopies, to analyze three samples from different geological formations in the Tampico-Misantla basin: Zuloaga (S1), Agua Nueva (S2) and Abra (S3). The rocks are predominantly composed of calcite with slight impurities of other chemical elements. X-ray diffraction (XRD) and scanning electron microscopy/elemental dispersive spectroscopy (SEM/EDS) confirmed a high calcium percentage, and UV–vis spectra revealed the presence of naphthenic and aromatic compounds. Despite intracrystalline porosity in all samples, S2 and S3 exhibited more defined grain shapes. It was observed the decrease in crystallinity as % and crystal size in S3 after CO₂ injection, highlighting the structural alterations induced by this process, emphasizing the importance of understanding these changes for optimization of capture technologies. This work examines the potential morphological and structural impacts of CO₂ injection on carbonate rocks, anticipating an exploration of rock-fluid interactions, contributing to the development of CO₂ capture technologies in Mexican petroleum reservoirs.