Method for prolonging service life of screw pump by blending water into casing pipe sleeve of heavy oil well

The invention relates to a method for prolonging the service life of a screw pump by blending water into a casing pipe sleeve of a heavy oil well, comprising the steps of: adopting a same heat ratio computing method to compute a concrete water blending and temperature reducing scheme according to concrete conditions, i.e. known oil reservoir well conditions, production modes, and the like; and effectively reducing the temperature of generated liquid inside a wellhole by directly blending the water into a casing pipe so as to achieve the purpose of effectively protecting the rubber of a rotor of the screw pump and protecting the screw pump to normally and continuously produce. The water blending and temperature reducing method of the casing pipe sleeve of the heavy oil well has reasonable design, easy implement and good effect, can effectively reduce the temperature of the bottom liquid of a gasoline well and the heavy oil well and the damage of the rotor of the screw pump, prolong the service life of the scre