关键词: 井壁失稳, 坍塌压力, 强度准则, 钻井速度, 准噶尔盆地

Abstract: There is a lack of theoretical guidance and practical optimization method for the selection of strength criteria in wellbore stability evaluation in field，which may lead to the deviation of the drilling fluid density used. The collapse pressure calculated by six strength criteria widely used in rock engineering had been compared. The results show that the collapse pressure calculated by D-Pi criterion is the highest，followed by M-C criterion，H-B criterion and D-Pc criterion；the collapse pressure calculated by LAm criterion and W-Cm criterion is in the middle. Through field practice，a set of method for strength criteria optimization and application has been summarized. Applying the optimized strength criterion to the wellbore stability evaluation in later drilling to optimize the design and use of drilling fluid density can not only ensure the wellbore stability，but also improve the drilling speed and oil and gas discovery. This method has been applied in some blocks and strata of Junggar Basin，and achieved good results，which is proved to be of popularization and application value.

Key words: wellbore instability, collapse pressure, strength criterion, drilling speed, Junggar Basin