Hyperbranched polyglycerols derivatives as cetyltrimethylammonium bromide nanocarriers on enhanced oil recovery processes

Abstract

In this work, the efficiency of partially hydrophobized hyperbranched polyglycerols (HPG11 and HPG12) as cetyltrimethylammonium bromide (CTAB) carriers was evaluated to prevent surfactant losses by adsorption on reservoir rocks surface during enhanced oil recovery (EOR) processes. Interactions between surfactant and polymers were studied by conductivity, zeta potential, and particle size measurements showing that complexes were formed between the components. The ability of PG, HPG11, HPG12 and those complexes to reduce the interfacial tension (IFT) was verified and one of the complexes was able to reduce the IFT to values under 1.0 mN/m, suggesting the occurrence of a synergy between the components. Molecular dynamics simulations indicated the preferential sites of interaction between surfactants and HPGs. HPG11:CTAB and HPG12:CTAB complexes' ability to permeate an unconsolidated porous medium and deliver the surfactant at the water–oil interface, increasing oil production, was evaluated through transport and oil displacement tests, and the results showed that the HPG12:CTAB complex led to almost 90% of oil recovery.

Synergistic Interaction of Hyperbranched Polyglycerols and Cetyltrimethylammonium Bromide for Oil/Water Interfacial Tension Reduction: A Molecular Dynamics Study

“…The system with 150 HPG molecules can reduce the IFT of the pure system by almost two times, while the IFT of the CTAB system is ten times lower than that of the pure system. However, when both surfactants are present, either CTAB+HPG­(l) or CTAB+HPG­(h), the IFT of the pure water/oil interface is reduced a hundred times, showing that the CTAB and HPG act synergistically to lower the interfacial tension, as observed experimentally by Ferreira et al…”

“…15 The authors proposed that the high density of functional groups available in the three dimensions for interaction/reaction in the structure of the HPG is one of the main factors for its superior performance in oil recovery when compared with linear polymeric structures. 16,17 We have shown 12 that with more sites available to interact with the surfactant molecules, the HPG can act as a carrier. However, our simulations were then performed in an aqueous solution.…”

“…Here, we include a complex interfacial system to provide insight into the enhanced extraction mechanism. The understanding of the behavior of hyperbranched polyglycerols at the water/oil interface can contribute to the planning of the architecture of new hyperbranched polymers as surfactant carriers, with a performance superior to that observed before Ferreira et al 12 Moreover, this knowledge can also contribute to the design of new compounds that could be applied in other systems, including drug carriers that act at biological water/oil interfaces.…”

“…On the other hand, in a recent work, Ferreira et al obtained a high performance in oil recovery by associating CTAB molecules with partially hydrophobic hyperbranched polyglycerol (HPG), a peculiar structure obtained by anionic, ring-opening multibranching polymerization of glycidol , or glyceryl carbonate . The authors proposed that the high density of functional groups available in the three dimensions for interaction/reaction in the structure of the HPG is one of the main factors for its superior performance in oil recovery when compared with linear polymeric structures. , …”

“…We have shown that with more sites available to interact with the surfactant molecules, the HPG can act as a carrier. However, our simulations were then performed in an aqueous solution.…”