Method for predicting fatigue life of high-temperature, high-pressure and high-yield tubing string

The invention discloses a method for predicting the fatigue life of a high-temperature, high-pressure and high-yield tubing string. The method comprises the steps: obtaining alternating stress Si of different positions of the tubing string according to a tubing string dynamic model; according to the alternating stress Si of different positions of the tubing string and the corrected fatigue curve of the tubing string, obtaining the cycle index Ni; according to the alternating stress Si of different positions of the tubing string, carrying out statistics by adopting a rain flow method to obtain an alternating stress cycle index ni; according to the cycle index Ni and the alternating stress cycle index ni, calculating the fatigue life L'of the tubing stringbased on the Miner fatigue theory. The tubing string vibration response and the tubing S-N curve are combined, the Miner linear cumulative damage theory is introduced,the three-high gas well tubing string fatigue life prediction method is formed, the three-hig