Method for calculating critical discharge of horizontal well cement slurry

The invention discloses a method for calculating the critical discharge of horizontal well cement slurry, and belongs to the technical field of oil and gas cementing. The method includes the following steps of: determining the temperature of a well bottom of a horizontal well and the pressure of the well bottom of the horizontal wellaccording to well track data and temperature log data; calculating a value range of a revolving speed corresponding to a value range of a shearing speed according to an instrumental constant of a rheometer on the premise of the known value range of the shearing speed of the cement slurry; selecting a revolving speed level of the rheometer in the value range of the revolving speed; measuring readings corresponding to different revolving speed levels, of the cement slurry under the temperature of the well bottom and the pressure of the well bottom; calculating the shearing speed and the shearing stress of the cement slurry; calculating rheological parameters according to the types o