Speaker
Description
Matrix acid stimulation in carbonate rocks is governed by coupled acid–rock interactions that control reactive transport, wormhole formation, and the enhancement of pore connectivity, all strongly influenced by pore-scale heterogeneity. Mineralogical variability, particularly between calcite and dolomite, plays a key role due to their distinct dissolution kinetics, directly impacting reactive flow behavior. However, the influence of grain size and mineral spatial distribution on these processes remains not fully understood. In this study, a highly dolomitized carbonate sample from the Piauí Formation (Parnaíba Basin) was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and porosity measurements, followed by static dissolution experiments in 1 M HCl. The results confirm preferential dissolution of calcite relative to dolomite and highlight the strong control of mineralogical heterogeneity on dissolution patterns. Notably, differences in mineral distribution observed by Backscattered Electron (BSE) SEM images, crystal size observed by distribution observed by secondary electron (SE) SEM images, and the presence of resistant phases such as quartz, affecting local flow pathways, impact the reactive behavior of the sample. Under unpressurized conditions and short reaction times, limited acid penetration led to transport-limited, surface-controlled dissolution, restricting the evolution of porosity within the pore network. These findings demonstrate that, beyond bulk mineralogy, textural and pore-scale heterogeneity exert a fundamental control on reactive transport, emphasizing the need to incorporate such features into predictive models of dissolution in heterogeneous porous media.
| Country | Brasil |
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