Preparation method of supercritical carbon dioxide thickener for tight oil and gas reservoir

A method for preparing a supercritical carbon dioxide thickener for a tight oil and gas reservoir, comprising following steps:

• (1) preparing P-toluene perfluoroalkyl ethylenesulfonates (TFES), which further comprises following sub-steps:
• after adding a perfluoroalkyl alcohol and a P-toluenesulfonyl chloride in a three-neck flask, wherein a molar ratio of the perfluoroalkyl alcohol and the P-toluenesulfonyl chloride is 1:1.1-1.2, and adding a pyridine;
• forming a system;
• wherein the system has reacted for 3 h under stirring thoroughly;
• maintaining a temperature at 0-20° C.;
• adding filter paper and carrying out ultrasonic dispersion for 1 h after a reaction is over;
• after removing unreacted residue P-toluenesulfonyl chloride and the filter paper;
• forming a system;
• washing the system with 15% dilute hydrochloric acid many times to remove the pyridine and collect a white solid;
• washing the white solid with distilled water for multiple times, drying the white solid by a vacuum drying oven at 40° C. for 3 h to prepare an intermediate product (I) TFES;
• (2) preparing intermediate product (II) (1,3-bis(perfluoroalkyl ethoxy) isopropyl-2-tertbutyl carbamate) (PFEIT), which further comprises the following sub-steps:
• adding a 1,3-dihydroxy-propane-2-tert-butyl carbamate and the intermediate product (I) TFES in a three-neck flask, wherein a molar ratio of the 1,3-dihydroxy-propane-2-tert-butyl carbamate and the TFES is 2.1-2.2:1;
• then adding potassium carbonate and N,N-dimethylformamide;
• forming a system;
• wherein the system has been reacted for 4 h under stirring thoroughly at 40° C.;
• washing a reaction liquid with distilled water repeatedly after a reaction process is over;
• then carrying out vacuum drying to collect an intermediate product (II) PFEIT;
• and
• (3) preparing a final product (III) 1,6-bis[1,3-bis(perfluoroalkyl ethoxy) isopropyl-2-urea] hexane (PFEIUH), which further comprises the following sub-steps:
• adding a mixture of methylene chloride and trifluoroacetic acid in a three-neck flask;
• wherein a volume ratio of the methylene chloride and the three trifluoroacetic acid is 2:1;
• adding the intermediate product (III) PFEIT to the mixture;
• maintaining a temperature at 45° C.;
• reacting for 2 h;
• adding the methylene chloride for extracting for 3 times to form an organic layer;
• drying the organic layer with a Na2SO4;
• adding 1,6-hexamethylene diisocyanate (HMDI), wherein a molar ratio of the HMDI and the PFEIT is 1:2.05-2.10, reacting under a temperature of 50° C. for 2 h, washing a crude product with a mixture of ethyl acetate and benzene for multiple times;
• filtering and carrying out vacuum drying to collect a final product (III) PFEIUH, wherein a perfluoro alkyl is one from these groups C5F11, C6F13, C7F15, C8F17, C9F19, C10F21.