POSSIBILITY OF DRILL STEM BUCKLING IN INCLINED HOLE

On the basis of energy method,the possibility of drill stem buckling in inclined straight hole is studied. The model shows that in most cases there is no probability of drill stem buckling. When deviated angle exists,it is not true that the longer the drillstring, the smaller the critical axial load. The critical deviated angles are calculated, which indicate the possibilities of buckling under some classical drill pipe, given axial loads.