Cause Analysis and Safety Measures for Borehole Sloughing Type of Collapsing

The borehole sloughing type of collapsing is very common in the drilling process. And this condition may result in drill string sticking and enlarged hole and induce other underground complex conditions, which may affect the successful drilling and underground safety. This thesis analyzes the elements resulting in borehole sloughing, components and properties of the drilling fluid system, and drilling engineering factors; and it proposes the niche targeting but feasible prevention measures of instability from components and properties of drilling fluid to drilling process and operation channels through elements analysis of borehole sloughing type of collapsing; in addition, the thesis describes the implementation of multiple coordination and comprehensive measures for valid prevention of such collapsing in actual drilling process.