Ultra-low interfacial tension self-assembly carbon dioxide foam oil-displacing agent suitable for low-permeability reservoir as well as preparation method and application of oil-displacing agent

The invention provides an ultralow interfacial tension self-assembly carbon dioxide foam oil displacement agent suitable for a low-permeability reservoir. The oil displacement agent is prepared from the following components in percentage by weight: 0.2-0.3% of {bis [N-methyl-N-(3-dodecyloxy-2-hydroxyl) propyl-N-(2-hydroxy-3-sodium sulfonate) propyl] ammonium chloride} ethane, 0.2-0.3% of cocamidopropyl betaine, 0.2-0.3% of sodium dodecyl benzene sulfonate and the balance of water. The cleaning agent is prepared from the following components in percentage by weight: 0.1 to 0.35 percent of dodecyl dimethyl amine oxide, 0.02 to 0.07 percent of sodium salicylate, 0.04 to 0.14 percent of chelating agent, 5 to 7 percent of inorganic salt and the balance of water. The invention also provides a preparation method and application of the self-assembled carbon dioxide foam oil-displacing agent with ultralow interfacial tension. The self-assembled carbon dioxide foam oil-displacing agent is good in salt resistance and ac