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CN-119306883-B - Reverse demulsifier and preparation method and application thereof

CN119306883BCN 119306883 BCN119306883 BCN 119306883BCN-119306883-B

Abstract

The application discloses a reverse demulsifier and a preparation method and application thereof, wherein the reverse demulsifier comprises a compound shown in a structural formula I, n is less than 792, m is less than 447, a is more than or equal to 3 and less than or equal to 10, R 1 、R 2 、R 3 is chain alkyl, and the number of carbon atoms in R 1 is more than or equal to 1 and less than or equal to n 1 ≤12,R 2 、R 3 , and the number of carbon atoms in R 1 is more than or equal to 0 and less than or equal to n 2 and less than or equal to 2. The reverse demulsifier has the advantages that the molecular structure of the reverse demulsifier contains both amphiphilic groups of alkyl ester groups (lipophilic ends) and hydroxyl ammonium groups (hydrophilic ends), the displacement effect is better at an oil-water interface film, the polarity of asphaltene can be reduced, the asphaltene has better dispersion capacity at the oil-water interface, the asphaltene can rapidly migrate from emulsion to the interface and be adsorbed to the oil-water interface, the branched chains and the main chain are shaped like saw teeth integrally, the molecular structure is highly branched, the surface tension of produced water can be effectively reduced, the destabilization of the oil-water interface is promoted, and the water-oil balance is broken.

Inventors

  • CHEN SHUANG
  • LIU HUIE
  • SUN WEIPENG
  • YUAN XIAODI

Assignees

  • 中国石油大学(华东)

Dates

Publication Date
20260512
Application Date
20241012

Claims (10)

  1. 1. A reverse demulsifier, comprising a compound represented by the structural formula I: ; A formula I; in the formula I, n is less than 792, m is less than 447, a is more than or equal to 3 and less than or equal to 10, R 1 、R 2 、R 3 is chain alkyl, wherein the number of carbon atoms in R 1 is more than or equal to 1 and less than or equal to n 1 ≤12,R 2 、R 3 and the number of carbon atoms in R is more than or equal to 0 and less than or equal to n 2 and less than or equal to 2, and the auxiliary agent of the reverse demulsifier is selected from one or more of cationic polyacrylamide, chitosan quaternary ammonium salt and polyaluminium chloride.
  2. 2. The method for preparing the reverse demulsifier of claim 1, comprising the steps of: s1, mixing dimethylaminoethyl enoate and enoate with a solvent, introducing nitrogen, and then adding an initiator for polymerization to obtain a polymer; s2, mixing the polymer obtained in the step S1 with a solvent, and adding halogenated alcohol to react to obtain the reverse demulsifier.
  3. 3. The method for preparing the reverse demulsifier as claimed in claim 2, wherein the initiator is one or more selected from azobisisobutyronitrile, potassium persulfate and ammonium persulfate.
  4. 4. The method for preparing a reverse demulsifier according to claim 2, wherein in the step S1, the volume ratio of dimethylaminoethyl enoate to the enoate is 1:0.5-2, and the volume of the solvent is equal to the sum of the volumes of dimethylaminoethyl enoate and the enoate.
  5. 5. The method for preparing a reverse demulsifier according to claim 2, wherein the polymerization reaction temperature in the step S1 is 45-70 ℃, and/or, The reaction temperature in the step S2 is 70-80 ℃.
  6. 6. The method for preparing a reverse demulsifier according to claim 2, wherein the molar ratio of the polymer to the halohydrin in step S2 is 0.3-1:1, and the volume of the solvent is equal to the volume of the polymer.
  7. 7. The method for preparing the reverse demulsifier as claimed in any one of claims 2 to 6, wherein the material obtained by adding the halohydrin in the step S2 is put into a rotary evaporator to remove the solvent, and washed and dried to obtain the reverse demulsifier.
  8. 8. Use of the reverse demulsifier of claim 1 or the reverse demulsifier prepared by the preparation method of any one of claims 2 to 7 in demulsification treatment of oilfield produced water.
  9. 9. The use according to claim 8, characterized in that the step of applying comprises adding the reverse demulsifier to the oilfield produced water sample to be treated, stirring and adding an adjuvant, and standing.
  10. 10. The use according to claim 9, wherein the weight ratio of the reverse demulsifier to the oilfield produced water sample is 1:2 x 10 4 ～1×10 5 and the weight ratio of the adjuvant to the reverse demulsifier is 1:5 x 10 4 ～1×10 5 .

Description

Reverse demulsifier and preparation method and application thereof Technical Field The application relates to the technical field of demulsifiers, in particular to a reverse demulsifier and a preparation method and application thereof. Background Most of oil fields in China enter a tertiary oil recovery stage, and chemical agents such as polymers, alkali liquor, surfactants and the like are added in the oil recovery process to make the components of crude oil more complex, so that the water content and demulsification difficulty of the crude oil are increased, and the dehydration cost of the crude oil is increased and energy is wasted. Especially, like the crude oil rich in asphaltene, the multi-layer multi-emulsion formed by the method has the characteristics of large viscosity, small oil-water density difference and poor fluidity, is very stable, and causes high demulsification temperature and dosage. The natural surfactants such as asphaltene in the crude oil are adsorbed on the oil-water interface to form an interfacial film with certain strength, so that the difficulty of oil-water separation is increased. At present, a large number of mature and widely applied traditional polyether demulsifiers in China have difficulty in meeting the production requirements of efficient and rapid demulsification of oil fields due to low dehydration rate, low dehydration speed and the like. Disclosure of Invention The invention provides a reverse demulsifier and a preparation method thereof, which are used for solving the technical problems of low dehydration rate and low dehydration speed in the prior art. In order to achieve the above purpose, the technical scheme provided by the invention is as follows: In a first aspect of the invention, there is provided a reverse demulsifier comprising a compound of formula I: in the formula I, n is less than 792, m is less than 447, a is more than or equal to 3 and less than or equal to 10, R1, R2 and R3 are all chain alkyl, wherein the number of carbon atoms in R1 is more than or equal to 1 and less than or equal to 12, and the number of carbon atoms in R2 and R3 is more than or equal to 0 and less than or equal to 2. In a second aspect of the present invention, a preparation method of the reverse demulsifier is provided, including the following steps: s1, mixing dimethylaminoethyl enoate and enoate with a solvent, introducing nitrogen, adding an initiator for polymerization to obtain a polymer, and S2, mixing the polymer obtained in the step S1 with the solvent, and adding halohydrin for reaction to obtain the reverse demulsifier. Further, the initiator is selected from one or more of azodiisobutyronitrile, potassium persulfate and ammonium persulfate. Further, in the step S1, the volume ratio of the dimethylaminoethyl enoate to the enoate is 1:0.5-2, and the volume of the solvent is equal to the sum of the volumes of the dimethylaminoethyl enoate and the enoate. Further, the temperature of the polymerization reaction in the step S1 is 45-70 ℃. Further, the reaction temperature in the step S2 is 70-80 ℃. Further, in the step S2, the molar ratio of the polymer to the halohydrin is 0.3-1:1, and the volume of the solvent is equal to the volume of the polymer. And further, adding a substance obtained after the halohydrin reaction in the step S2, putting the substance into a rotary evaporator to remove a solvent, and washing and drying to obtain the reverse demulsifier. In a third aspect, the invention provides an application of the reverse demulsifier in demulsification treatment of oilfield produced water. Further, the application step comprises the steps of adding the reverse demulsifier into an oilfield produced water sample to be treated, stirring, adding an auxiliary agent, and standing. Further, the weight ratio of the reverse demulsifier to the oilfield produced water sample is 1:2×10 4～1×105, and the weight ratio of the auxiliary agent to the reverse demulsifier is 1:5×10 4～1×105. The reverse demulsifier provided by the invention has the advantages that the molecular structure contains the amphiphilic groups of alkyl ester groups (lipophilic ends) and hydroxyl ammonium groups (hydrophilic ends), the displacement effect is better at the oil-water interface film, the polarity of asphaltene can be reduced, the asphaltene has better dispersion capacity at the oil-water interface, can quickly migrate from emulsion to the interface and be adsorbed to the oil-water interface, the adsorbed asphaltene can not continuously exist on the interface under the action of external force, finally, the interface is unstable, in addition, the branched chain and the main chain are integrally shaped like saw teeth, the molecular structure is highly branched, the surface tension of produced water can be effectively reduced, the instability of the oil-water interface is promoted, and the water-oil balance is broken. The reverse demulsifier contains ammonium ions, can ionize after being dissolved