Mechanism of expanding swept volume by nano-sized oil-displacement agent

The effect of expanding swept volume by iNanoW1.0 nanoparticles in ultra-low permeability core was studied by low-field nuclear magnetic resonance(LF-NMR)technology,and the mechanism of expanding swept volume was explained by oxygen spectrum nuclear magnetic resonance(17O-NMR)experiments and capillarity analysis.The results of the LF-NMR experiment show that the nano-sized oil-displacement agent iNanoW1.0 could increase the swept volume by 10%-20%on the basis of conventional water flooding,making water molecules get into the low permeable region with small pores that conventional water flooding could not reach.17O-NMR technique and capillary analysis proved that iNanoW1.0 nanoparticles could weaken the association of hydrogen bonds between water molecules,effectively change the structure of water molecular clusters,and thus increasing the swept volume in the low permeable region.The ability of weakening association of hydrogen bonds between water molecules of iNanoW1.0 nanoparticles increases with its mass fraction and tends to be stable after the mass fraction of 0.1%.

Molecular dynamics simulation study onπ-πstacking of Gemini surfactants in oil/water systems

Whereas theπ-πstacking interactions at oil/water interfaces can affect interfacial structures hence the interfacial properties,the underlying microscopic mechanism remains largely unknown.We reported an all-atom molecular dynamics(MD)simulation study to demonstrate how the Gemini surfactants with pyrenyl groups affect the interracial properties,structural conformations,and the motion of molecules in the water/n-octane/surfactant ternary systems.It is found that the pyrenyl groups tend to be vertical to the interface owing to theπ-πstacking interaction.Besides,a synergistic effect between theπ-πinteraction and steric hindrance is found,which jointly affects the coalescence of liquid droplets.Therefore,the existence of aromatic groups and a moderate number of surfactants helps to form microemulsion.This work provides a molecular understanding of Gemini surfactants with aromatic groups in microemulsion preparation and applications.

Functionalized Hierarchical ZSM-5 Zeolites for the Viscosity Reduction of Heavy Oil at Low Temperature

Herein,we propose a novel approach to reduce the viscosity of heavy oil by functional hierarchical CTMS-ZSM-5-PTMS zeolites.CTMS-ZSM-5-PTMS zeolites synthesized by asymmetric modification and selective alkali etching can reduce the viscosity of heavy oil through adsorbing asphaltenes.This method can reduce the viscosity of heavy oil from hundreds of thousands mPa·s to about ten thousand mPa·s.The work provides an economical and environmentally friendly candidate for heavy oil viscosity reduction under low-temperature conditions.