The subject of rock–fluid interaction is important in cases where flow through porous media is occurring. One special case is when the fluid reacts with the porous matrix. In this case, the mass transfer and reaction rate control the dissolution pattern. This article aimed to study the interaction between an acid nanoemulsion system and a carbonate porous media. Nanoemulsions were developed to retard the rock’s dissolution and to promote the formation of conductivity channels. Nanoemulsions were prepared using ALK100 (alkyl alcohol ethoxylate) and RNX110 (alkylphenol ethoxylate) (nonionic surfactants), sec-butanol (co-surfactant), xylene isomers (oil phase), and a solution of HCl (aqueous phase). The obtained systems were characterized in terms of surface tension, droplet diameter, and reactivity. X-ray fluorescence/diffraction (XRF/XRD) and X-ray microtomography (microCT) were performed on carbonate porous media samples treated with the acid systems in order to observe the effects of the fluid–rock interaction. The results showed that the acid nanoemulsion, presenting a low oil content formulation, showed the low surface tension and droplet size characteristic of nanoemulsions. It was experimentally verified that the reactivity in the nanoemulsion media was mass-transfer-retarded, and that the wormhole pattern was verified under the studied conditions.

Aromatic solvents, such xylene and toluene, are widely used in the organic damage removal operations, although increasing environmental requirements have encouraged the research for new environmental-friendly solutions to replace these solvents. Microemulsions are thermodynamically stable multicomponent systems known by their notable solubilization capability. This paper describes the preparation and investigation of a low-oil-content microemulsion system able to remove the organic damage and restore the permeability. The damage removal efficiency, for the microemulsion systems prepared, was comparable to xylene. The results showed that the proposed microemulsion formulation is a cost-effective and environment-friendly alternative to aromatic solvents.

Optimizing production in the mature fields of heavy oil reservoirs is still challenging. In most cases, conventional recovery techniques are not effective, although they are suitable for applying thermal recovery methods. Steam injection involves injecting steam into the reservoir where the heat exchange with the oil occurs. This promotes a reduction in oil viscosity and thus increases its mobility. One of the challenges of the EOR project is understanding how the presence of regions with contrasting properties, such as fractures, caves, and barriers, could affect the steam flow. This work investigates the impact of low-permeability barriers in the steam injection process. The barriers were created on a semi-synthetic reservoir characteristic of Brazilian onshore mature fields. We used the three-phase pseudo-compositional reservoir simulation STARS (Steam Thermal Advanced Processes Reservoir Simulation) for simulations. Our results show that the shape, number, and arrangement of barriers in a porous medium can affect the amount of oil recovered. They may also be able to anticipate or delay oil production.