System classification of failures in drilling

The problem of failures classification in drilling is considered in the paper. The following classification signs are used: failure source, object of failure, factors influencing the process of occurrence and liquidation of failures, scales and consequences. Detailed elaboration on various groups of objects of failures is done for the most important sources of failures. The received results can be used in the course of the analysis of emergencies for selecting a way of struggle against failures and complications in drilling.