Abstract:Statistics of drilling complex events indicated that all kinds of complex events totally happened 129 times in group 6, group 601 and group 7 wells, and seriously affected safety and progress of drilling engineering in Qunkuqiake area. In this paper, through analyzing rock mineral composition and physical and chemical conditions of the rock, combining with practical problems encountered in drilling,main influencing factors of sidewall instability, the function and importance of drilling fluid in the drilling process have been analyzed. It will provide a reasonable basis for the research of sidewall stability in this area.