2-D纳米黑卡油水界面微观驱油机理分子动力学模拟

Molecular Dynamics Simulation Research on Microscopic Mechanism of Two-dimension（2-D）Black Nanosheet at Water/Oil Interface

冯阳 侯吉瑞 杨钰龙 王栋森 王立坤 程婷婷 刘彦伯

FENG Yang HOU Jirui YANG Yulong WANG Dongsen WANG Likun CHENG Tingting LIU Yanbo

新型纳米材料2-D 纳米黑卡已被证实可有效提高低渗-致密油藏采收率，展现出优异的油水界面特性。但是2-D 纳米黑卡与油水界面相互作用的微观机理仍不明确。应用Lammps 建立2-D 纳米黑卡油水界面模型，针对常温常压（298 K，1 atm）条件下2-D 纳米黑卡在油水界面的特性进行分子动力学模拟，分析2-D 纳米黑卡个数对不同分子在油水界面的密度分布、油水界面厚度、油水界面覆盖率、分子间相互作用能和界面张力变化率等5个关键参数的影响规律。模拟结果表明：当2-D纳米黑卡界面覆盖率近似为1 时，界面处油水及纳米片分子密度分布基本达到稳定，2-D纳米黑卡界面密度峰值几乎不再增长，密度峰变宽；油水界面厚度为24.4 ?，油水界面相互作用能为-4164 kcal/mol，界面张力比率为0.767，且这3 个量达到相对稳定状态。本研究可对2-D 纳米黑卡室内实验和矿场应用浓度优选提供理论依据和指导，为纳米片驱油机理的研究奠定理论基础。

A flaky two-dimensional（2-D）black nanosheet has been proven to be effective in enhancing oil recovery in low permeability and tight reservoirs， showing excellent water/oil （W/O） interface characteristics. However， the microscopic mechanism of 2-D black nanosheet interaction with W/O interface is still unclear. A molecular dynamics study was presented to reveal the characteristics of 2-D black nanosheet at W/O interface which was performed using the Lammps package at room temperature and atmospheric pressure（i.e.，298 K and 1 atm）. The influence of the number of 2-D black nanosheet on the density distribution of different molecules at the W/O interface，the thickness of the W/O interface，the rate of interface coverage（RIC）， the intermolecular interaction energy，and the rate of interfacial tension，was analyzed. The results showed that when the 2-D black nanosheets number was four，that is，RIC was approximately one，the W/O interface density distribution was stable in the MoS2 nanosheets W/O interface model. The peak density of the 2-D black nanosheets’interface almost did not increase，but the peak density became wider. Moreover，the interface thickness was 24.4 ?；the interaction energy was ? 4164 kcal/mol，and the interfacial tension ratio was 0.767 at the W/O interface，which was relatively stable. The study of 2-D black nanosheet can provide theoretical basis and guidance for their laboratory experiment and concentration optimization of field application，and lay a theoretical foundation for the study of nanosheet oil displacement mechanism.

10.19346/j.cnki.1000-4092.2022.02.021