Synthesis and molecular simulation of terpolymer viscosity reducer for heavy oil

doi:10.11949/0438-1157.20241489

Abstract

Abstract:

Oil-soluble viscosity reducers are considered to be promising viscosity reducers in heavy oil production and transportation due to their low energy consumption and simple operation. However, they have problems such as low viscosity reduction efficiency and unclear viscosity reduction mechanism. By employing octadecyl methacrylate, benzyl methacrylate and maleic anhydride as monomers, a terpolymer viscosity reducer SBM was synthesized through free radical polymerization. The terpolymer was characterized by FTIR, ¹H NMR, and TGA to determine the structures and properties. The viscosity reduction effect on different heavy oils at 50℃ was investigated and compared with that of two commercial viscosity reducers. Furthermore, the mechanism of viscosity reduction in heavy oil with different asphaltene was studied by molecular dynamics simulation. The research shows that the viscosity reducer has the best viscosity reduction effect on Shengli heavy oil, with an apparent viscosity reduction rate of 66.67% and a net viscosity reduction rate of 27.34%. The viscosity reduction effect of oil1 is better than oil 2. In oil 1, SBM destroys the asphaltene structure of parallel stacking by breaking π-π interaction. In oil 2, SBM break up large aggregates by breaking hydrogen bonds.

Key words: heavy oil, oil-soluble viscosity reducer, kinetics, molecular simulation, polymers, synthesis

摘要：

油溶性降黏剂因能耗低、操作简便，被认为是稠油开采和运输过程中极具应用前景的降黏剂，但存在降黏效率低、降黏机理尚不明确等问题。以甲基丙烯酸十八酯、甲基丙烯酸苄酯和马来酸酐为单体，通过自由基聚合反应合成了三元共聚物降黏剂SBM，探究其降黏效果，采用分子动力学模拟方法对其在不同类型稠油中的降黏过程进行微观机理研究。研究结果表明，该降黏剂对胜利稠油降黏效果最好，表观降黏率可达66.67%，净降黏率可达27.34%；对原油1的降黏效果优于原油2，在原油1中降黏效果主要与π-π相互作用有关，在原油2中降黏效果主要与氢键相关。

关键词: 稠油, 油溶性降黏剂, 动力学, 分子模拟, 聚合物, 合成

CLC Number:

TE 39

Liang QIAO, Shang LI, Xinliang LIU, Ming WANG, Pei ZHANG, Yingfei HOU. Synthesis and molecular simulation of terpolymer viscosity reducer for heavy oil[J]. CIESC Journal, 2025, 76(7): 3686-3695.

乔亮, 李尚, 刘新亮, 王明, 张沛, 侯影飞. 三元共聚物稠油降黏剂的合成及分子模拟研究[J]. 化工学报, 2025, 76(7): 3686-3695.

Figures/Tables 13

Table 1 Physical properties of heavy oil

原油	黏度/(mPa·s)	饱和分/%(质量)	芳香分/%(质量)	胶质/%(质量)	沥青质/%(质量)
胜利稠油	9828	22.47	25.21	32.78	12.69
辽河稠油	7392	23.69	27.47	27.25	14.97

Fig.1 Synthesis flow diagram and reaction route of SBM

Fig.2 Schematic diagram of simulation box model and molecular structure

Table 2 Molecular composition of each simulated heavy oil system

系统	饱和分	芳香分	胶质	沥青质1	沥青质2	SBM
Oil1	60	80	80	20	—	—
Oil1+SBM	60	80	80	20	—	20
Oil2	60	80	80	—	30	—
Oil2+SBM	60	80	80	—	30	20

Fig.3 FTIR spectra (a)， TGA curves (b) and 1H NMR spectra (c) of SBM

Table 3 Effect of SBM addition on different heavy oil

原油	表观降黏率/%	净降黏率/%
胜利稠油	66.67	27.34
辽河稠油	58.60	21.78

Fig.4 Viscosity reduction effect of different viscosity reducers

Fig.5 Viscosity changes and corresponding viscosity reduction rate of each system before and after addition of SBM

Fig.6 Snapshots of each system (only SBM, asphaltenes and resins are shown)

Fig.7 Total interaction energy between asphaltene and resin in each system

Fig.8 Changes in number of hydrogen bonds before and after addition of SBM in each system

Fig.9 RDF curves and CN between asphaltene and resin in each system

Fig.10 MSD curves and diffusion coefficients in each simulated system

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