渤海典型稠油活性组分对油水界面性质及乳状液稳定性的影响

Effect of Active Components in Bohai Heavy Oil on Water-oil Interfacial Properties and Emulsion Stability

华 朝 张 健 李 浩 宋 夏 靖 波 王金本

HUA Zhao ZHANG Jian LI Hao SONG Xia JING Bo WANG Jinben

为了揭示原油组分分子组成与各组分界面性质、 乳化性能间的关系， 阐明油水界面性质变化和原油乳化机理， 用极性分离法将渤海某油田稠油分离为沥青质、 胶质、 剩余分三个组分， 含量分别为 5.45%、 26.5%、 57.13%。通过红外光谱、 元素分析和高分辨质谱分析了三组分的分子组成， 采用界面张力仪、 界面黏弹性仪测定了各组分与模拟水间的界面特性。研究结果表明， 沥青质、 胶质中含有大量酸性化合物， 其中沥青质中酸性化合物的相对分子量高、 缩合度高且富集多杂原子化合物。0.55%沥青质、 5%胶质、 5%剩余分模拟油与模拟水间界面张力分别为 11.5、 20、 28 mN/m， 说明酸性化合物是原油中主要活性物质， 且多杂原子酸性化合物的界面活性更强。原油三组分模拟油的剪切黏度随剪切速率增加而下降， 在剪切速率为 0.02～0.4 rad/s时， 原油三组分/模拟水界面剪切黏度排序为沥青质>胶质>剩余分， 说明各组分形成的界面膜具有明显的结构特性， 沥青质尤为明显。原油与乙醇胺溶液能形成稳定的W/O型乳状液， 一周后仍无水相析出； 除去原油中沥青质后， 乳状液稳定性明显变差， 11 h后油水完全分层； 除去沥青质、 胶质后， 不能产生乳化现象， 说明沥青质、 胶质是渤海某油田稠油乳化的活性组分。图 6表1参 14

In order to reveal the relationship between the molecular composition of oil fractions and interfacial properties，emulsifying properties and clarify the mechanisms of oil-water interfacial properties change and crude oil emulsification，Bohai heavy oil was separated into asphaltene，resin and remaining fraction according to polarity difference，mass percents of three fractions being of 5.45%，26.5% and 57.13%，respectively. Molecular composition of three fractions was investigated by infrared spectrum，element analysis and high-resolution mass spectrometry. Moreover，interfacial tensiometer and interfacial viscoelastic instrument were used to study the interfacial properties. The results demonstrated that the asphaltene and resin was rich in acidic compounds. Moreover，the relative molecular weight，the degree of condensation and the content of heteroatom of acidic compounds in asphaltene were higher than that of resin. The interfacial tensions between model formation water and model oil of 0.55% asphaltene，5% resin，5% remaining oil，was 11.5 mN/m，20 mN/m，28 mN/m，respectively，which indicated that the acidic compounds in crude oil were the main interfacial active materials，which with heteroatoms exhibited stronger interfacial activity. The interfacial shearing viscosity of three fractions model oils decreased with increasing shear rate，meantime，at shear range of 0.02—0.4 rad·s-1，three fractions was arranged according to the interfacial shearing viscosity as follows：asphaltene>resin > remaining fraction，which indicated that the interfacial film formed had obvious structure，especially for asphaltene. The W/O emulsion formed by crude oil and ethanolamine solution presented high stability for more than a week. The stability decreased obviously by removing the asphaltene in crude oil，and the oil-water separated completely after 11 h；while，the emulsification did not appear as both of asphaltene and resin were removed，which suggested that the asphaltene and resin were the main active components for emulsification of Bohai heavy oil.

10.19346./j.cnki.1000-4092.2017.04.012