Contact interaction between bottom drillstring and borehole wall and its effect on drillstring failure;

In this paper,the basal contents and methods of the SVM technology are introduced and a drill stem failure learning model based on the SVM technology is established by learning small data samples to optimize the model in order to study the drill stem failure in drilling engineering.

The frequent drill stem failures were very important reasons for this phenomenon inthe oilfield after investigating.

Research on vibration problems which is the main reason causing bottom drilling tool failure,can reduce drilling tool damage and emergence of underground accidents.

This paper introduces the characteristics and the reasons of drilling tool failure, the judgment of downhole condition when drilling tool failure, fishing method of fish and prevention measure of drilling tool failure in drilling process of the nappe structure.

According to the statistical analysis of drilling pipe breaking accident in gas drilling in Puguang gas field, the results showed that drilling tool failure form in gas drilling was breaking, rifler drilling tool failure frequency was higher than air hammer drilling, .