Temperature-resistant and salt-resistant foaming agent for thermal recovery of offshore oilfield thickened oil and preparation method thereof

The invention discloses a temperature-resistant and salt-resistant foaming agent for offshore oilfield thickened oil thermal recovery and a preparation method thereof, and the temperature-resistant and salt-resistant foaming agent is obtained by sequentially adding an anionic surfactant, a nonionic surfactant, a salt-resistant stabilizer, a temperature-resistant stabilizer, an auxiliary agent and water into a reaction kettle and stirring until a uniform single-phase liquid is obtained. According to the invention, high foaming performance, temperature and salt resistance, oil washing performance and emulsification viscosity reduction performance are combined, so that one agent has multiple functions; in the aspect of selection of single agents in the formula, a single agent with high foaming performance is adopted as a main agent, and an auxiliary agent with temperature tolerance, salinity tolerance function improvement and mutual solubility enhancement functions is adopted as an auxiliary agent, so that the t