Evaluation method for simulating oil-water interface characteristics of alkylbenzene sulfonate surfactant based on molecular dynamics

Abstract

The invention discloses an evaluation method for simulating oil-water interface characteristics of an alkylbenzene sulfonate surfactant based on molecular dynamics. The method comprises establishing amolecular structure model of alkylbenzene sulfonate by adopting software; then, performing quantum chemistry calculation by utilizing software to obtain optimized molecular conformation and all-atomic structure charge parameters of alkylbenzene sulfonate; optimizing the molecular structure of alkylbenzene sulfonate to obtain optimized molecular topological structure parameters of the bond length,the bond angle and the dihedral angle; establishing a system model of oil-phase molecules, water molecules and alkylbenzene sulfonate by utilizing molecular accumulation software; and finally carrying out molecular dynamics calculation on a simulation system by utilizing molecular dynamics calculation software to evaluate the oil-water interface characteristics of alkylbenzene sulfonate. According to the method, the oil-water interface microcosmic action mechanism of the alkylbenzene sulfonate surfactant for chemical flooding can be clarified from molecular and atomic scales, and certain theoretical guidance is provided for application of alkylbenzene sulfonate in the field of oilfield chemical flooding.

Description

technical field [0001] The invention relates to the research field of oil-water interface and self-assembly characteristics of alkylbenzene sulfonate surfactants used in chemical flooding, in particular to an evaluation method for oil-water interface characteristics of alkylbenzene sulfonate surfactants based on molecular dynamics simulation. Background technique [0002] Due to its unique amphiphilic structure, surfactants can greatly increase oil recovery by changing rock wettability, reducing oil / water interfacial tension, and improving imbibition process. Agent / polymer binary flooding, surfactant / polymer / alkali ASP flooding and other chemical flooding stimulation technologies play an extremely important role. The research and development of high-efficiency and low-cost surfactants has always been a hot spot and difficult problem for chemical flooding surfactants. The ability of surfactants to reduce oil / water interfacial tension is an important basis for evaluating and s...

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Problems solved by technology

[0003] Due to the complexity of the chemical flooding surfactant application system, it is difficult to distinguish the interface and the bulk phase for research by experimental methods, and it is impossible to characterize and describe the characteristics and self-assembly behavior of the surfactant oil / water interface at the molecular level

Moreover, traditional experimental methods and thermodynamic analysis methods cannot obtain microscopic information at the molecular level, and can avoid the influence of unfavorable factors in actual experimental research. It is difficult to distinguish the interface from the bulk phase for research, and obtain alkylbenzene sulfonate relatively quickly. Characteristics and Microcosmic Action Mechanism of Surfactant Oil-Water Interface

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