On the problem of stability of rotation of the drill string in the process of destruction of rock
The paper deals with the problems of stability of rotation of a nonuniform drill string during deep well drilling. On the basis of the analysis of the developed mathematical model of interaction of the drill tool with a bottom hole taking into account dynamic processes proceeding in a nonuniform drill string, relations for determination of borders of steady rotation and a time stop ("spells") of the rock-crushing tool are received. This made it possible to solve the problem of identifying different zones in the field of control parameters (<i>P</i><sub>0</sub>, <i>n</i><sub>0</sub>) associated with the patterns of rotation of the drill tool, which, in turn, makes it possible to select the optimal mode parameters (<i>P</i><sub>0</sub>, <i>n</i><sub>0</sub>) taking into account the depth of the well <i>H</i>.