Special Oil & Gas Reservoirs ›› 2023, Vol. 30 ›› Issue (1): 161-168.DOI: 10.3969/j.issn.1006-6535.2023.01.023

• Drilling & Production Engineering • Previous Articles     Next Articles

Study of Macroscopic Aggregation Mechanism of Oil Droplets and Microscopic Interactions Between Oil Film Molecules

Huang Bin1,2, Nan Xiaohan1, Wang Yizhu3, Fu Cheng4, Zhu Yueming5, Zhang Lu1, Guo Wei1, Wang Siqi1   

  1. 1. Northeast Petroleum University, Daqing, Heilongjiang 166318, China;
    2. PetroChina Daqing Oilfield Co., Ltd., Daqing, Heilongjiang 163413, China;
    3. PetroChina Yumen Oilfield Company, Jiuquan, Gansu 735000, China;
    4. Chongqing University of Science and Technology, Chongqing 401331, China;
    5. PipeChina Harbin Company, Harbin, Heilongjiang 150010, China
  • Received:2022-04-24 Revised:2022-07-04 Online:2023-02-25 Published:2023-03-24

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Abstract: In order to study the microscopic interactions between oil droplets in the process of oil droplet coalescence, the coalescence behavior of emulsified oil droplets in oil well recovery fluid was studied by finite element simulation method, in combination with the emulsion stability experiments and molecular dynamics simulation technology, and the influencing factors of oil droplet coalescence were analyzed. The study results show that the fluid flow rate is relatively high at the location of the liquid film during the coalescence of the 2 oil droplets, and reaches stability after the coalescence is completed. There is no obvious correspondence between the size of oil droplets and the coalescence time, and when the radii of 2 oil droplets are different, the larger droplets move less; at the initial moment, there is an obvious boundary between oil film and water phase; the longer the carbon chain, the more stable the emulsion; under the condition of the same number of carbon atoms, the influence of crude oil components on the stability of emulsion is from small to large for saturated hydrocarbons, carbon-carbon double bonds, carbon-carbon triple bonds, and cycloalkanes; the increase of asphaltene content is the main reason for the increase of emulsification capacity and emulsion stability of emulsion system. This study is of great significance to improve the oil-water separation efficiency of crude oil and reduce the cost of crude oil storage and transportation.

Key words: emulsion, emulsified oil droplet, coalescence mechanism, microscopic characteristics, crude oil components, molecular dynamics

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