In-Plane Bending of a Drill String During its Compression in a Horizontal Borehole.

The stress-strain state of a drill string during its compression in a horizontal borehole is considered. The function of the elastic axis of the drill string as a wave curve is obtained, which enables one to improve the analytical models: evaluation of decrease of axial force depending on the drill string elastic axis shape, determination of the force of pressing of the string to borehole walls, and calculation of normal stresses in the cross section of drill pipes. [ABSTRACT FROM AUTHOR]