| 降压脱气对溶CO2原油乳液中水滴稳定性的影响 |
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| 引用本文： | 杨爽,李传宪,刘岱卫,邓志安,杨飞,孙广宇.降压脱气对溶CO2原油乳液中水滴稳定性的影响[J].石油学报(石油加工),2022,38(4):834-845. |
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| 作者姓名： | 杨爽 李传宪 刘岱卫 邓志安 杨飞 孙广宇 |
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| 作者单位： | 1. 西安石油大学 石油工程学院， 陕西 西安 710065;2. 中国石油大学(华东) 储运与建筑工程学院，山东 青岛 266580 |
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| 基金项目： | 国家自然科学基金项目（51704315）资助 |
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| 摘 要： | 通过对CO2在油/水/乳液中的溶解度、溶CO2原油的流动性、溶CO2后油-水间的界面特性、溶CO2原油乳液的稳定性、油-水界面压力变化的测试与计算，分析溶CO2原油乳液在降压脱气过程中水滴稳定性的变化规律。结果表明：溶CO2原油乳液中，沥青质等界面活性物质能够迅速地迁移并吸附于油-水界面，并微弱提高油相对CO2的溶解能力，并使得油-水界面张力快速降低，界面弹性模量增大，降低界面扩张损耗角；溶入CO2能够降低油相黏度，提高水滴沉降速率，使得原油乳液的分油率增大；降压脱气时，水相中CO2气泡的析出、长大，迫使水滴膨胀，降低界面上活性物质的浓度，减小了油-水界面压力，使得水滴的聚结稳定性变差，增大了原油乳液的分水率。
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| 收稿时间： | 2021-04-29 |
Effect of Degassing on Water Droplets Stability in Crude Oil Emulsion With Dissolved CO2 |
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| YANG Shuang,LI Chuanxian,LIU Daiwei,DENG Zhian,YANG Fei,SUN Guangyu.Effect of Degassing on Water Droplets Stability in Crude Oil Emulsion With Dissolved CO2[J].Acta Petrolei Sinica (Petroleum Processing Section),2022,38(4):834-845. |
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| Authors: | YANG Shuang LI Chuanxian LIU Daiwei DENG Zhian YANG Fei SUN Guangyu |
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| Affiliation: | 1. College of Petroleum Engineering, Xi’an Shiyou University, Xi’an 710065, China;
2. College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao 266580, China |
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| Abstract: | Effect of degassing on water droplets stability of crude oil emulsion with dissolved CO2 was investigated with using a high pressure emulsifying apparatus and emulsion stability test instrument. Various properties, including solubility of CO2 in oil/water/emulsion phase, flowability and stability of crude oil with dissolved CO2, interfacial characteristics between oil and water, and interfacial pressure of water droplets, were both tested and calculated. Changes of flocculation sedimentation stability (i.e., oil separation rate) and coalescence demulsification stability (i.e., water separation rate) of crude oil emulsion with dissolved CO2 at both constant and decreasing pressure conditions were analyzed based on interfacial characteristics (interfacial tension and interfacial modulus) and interfacial pressure. It was found that asphaltenes and other interfacial active substances in crude oil emulsion with dissolved CO2 could migrate and adsorb at oil-water interface quickly. They could reduce interfacial tension and improve structural strength of the interfacial film. This could increase interfacial elastic modulus, and reduce interfacial expansion loss angle. Viscosity of oil phase can be reduced after CO2 dissolving, and thus can help increase oil separation ratio of crude oil emulsion. CO2 bubbles can be formed and further developed in water phase during degassing process. This can expand water droplet and reduce the concentration of active substances at oil-water interface. Consequently, interfacial pressure of water droplet can be reduced, and droplet coalescence stability becomes poor, and thus increase crude oil emulsion water separation ratio. |
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