Abstract
We investigated the usage of two silica nanomaterials (surface-modified) and alkali in enhanced oil recovery through Amott spontaneous imbibition tests, interfacial tension (IFT) measurements, and phase behavior. We evaluated the wettability alteration induced by the synergy between nanomaterials and alkali. Moreover, numerical analysis of the results was carried out using inverse Bond number and capillary diffusion coefficient. Evaluations included the use of Berea and Keuper outcrop material, crude oil with different total acid numbers (TAN), and Na2CO3 as alkaline agent. Data showed that nanomaterials can reduce the IFT, with surface charge playing an important role in this process. In synergy with alkali, the use of nanomaterials led to low-stable IFT values. This effect was also seen in the phase behavior tests, where brine/oil systems with lower IFT exhibited better emulsification. Nanomaterials’ contribution to the phase behavior was mainly the stabilization of the emulsion middle phase. The influence of TAN number on the IFT and phase behavior was prominent especially when combined with alkali. Amott spontaneous imbibition resulted in additional oil recovery ranging from 4% to 50% above the baseline, which was confirmed by inverse Bond number analysis. High recoveries were achieved using alkali and nanomaterials; these values were attributed to wettability alteration that accelerated the imbibition kinetics as seen in capillary diffusion coefficient analysis.
Highlights
The authors showed that the highest additional recovery can be achieved by using NPs in secondary mode. They attributed the findings to various mechanisms, namely interfacial tension (IFT) reduction, the formation of micro emulsions and, most importantly, wettability alteration
To evaluate the effects of nanoparticles combined with alkali on wettability changes and IFT, we followed a series of steps that are described below and serve as a structure for understanding the results: 1
This work is complemented by the data presented by Neubauer et al [9]; Amott spontaneous imbibition experiments: Performed to evaluate wettability alteration and oil recovered over time by the imbibed fluid
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Investigated the rheology of oil-in-water emulsion formed by combining surface-modified NPs and hydrolyzed polyacrylamide (HPAM) polymer. Their results revealed that partially hydrophobic silica NPs have more favorable mobility from the bulk phase towards the oil–water interfaces, making them more effective in lowering IFT. The authors showed that the highest additional recovery can be achieved by using NPs in secondary mode They attributed the findings to various mechanisms, namely interfacial tension (IFT) reduction, the formation of micro emulsions and, most importantly, wettability alteration. With this study we aim to bridge knowledge gaps on the impact of surface-modified silica nanomaterials on enhanced oil recovery with a special focus on wettability alteration, by conducting interfacial tension measurements, phase behavior tests, and spontaneous imbibition tests. (2) the description of materials and methods; (3) the general approach of the paper; (4) the presentation of laboratory and modeling result; and (5) a summary and conclusions of the findings are presented
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