Temperature-resistant and salt-resistant reversed-phase emulsification viscosity reducer suitable for offshore oilfield and preparation method of temperature-resistant and salt-resistant reversed-phase emulsification viscosity reducer

The invention discloses a temperature-resistant and salt-resistant reversed-phase emulsification viscosity reducer suitable for offshore oilfields and a preparation method of the viscosity reducer. The viscosity reducer is obtained by sequentially adding a natural surfactant, a nonionic surfactant, a washing performance improver, an auxiliary agent and water into a reaction kettle and stirring at a low speed until a uniform single-phase liquid is obtained. According to the invention, the reversed-phase emulsification function and the washing function are combined, so that one agent has multiple functions; in the aspect of single agent selection in the formula, a high-performance single agent is adopted as a main agent, and auxiliary agents with anti-freezing, flowability improvement and mutual dissolution functions are adopted as auxiliary agents, so that a high-performance reversed-phase emulsification viscosity reducer system is formed. In addition, the environment-friendly requirement is considered, a natu