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 (P0, n0) associated with the patterns of rotation of the drill tool, which, in turn, makes it possible to select the optimal mode parameters (P0, n0) taking into account the depth of the well H.