Polyacrylamide (PAM) is a thickener commonly used in drilling fluids, but its high temperature resistance is limited. The thermal stability of PAM is generally around 150°C. When the temperature is higher than this, its molecular structure will degrade, thus affecting its thickening effect. Therefore, in high-temperature drilling operations, it is often necessary to use high-temperature resistant modified polyacrylamide or other thickeners with better high temperature stability, such as starch derivatives, cellulose derivatives or synthetic polymers.