DRILL STRING WITH BEND RESISTANT COUPLING

摘要

A drill string rod forms part of a drill string having one end configured with a male spigot portion to be received within a corresponding rod female sleeve end. To minimize stress concentrations within the threaded male and female coupling, the male spigot is configured with a large diameter or cross-sectional area being at least equal to the cross sectional area or diameter of the main length section.

主权项

1. A drill string rod to form a part of a drill string, the rod comprising:
a hollow elongate main length section extending axially between a first end and a second end; a male spigot portion provided at the second end having an externally threaded section and a non-threaded shank positioned axially intermediate the threaded section and a shoulder; the threaded section including at least one helical ridge and trough extending axially from the shank; the shoulder axially separating and projecting radially outward relative to the main length section and the spigot portion, the shank extending axially from an annular side surface of the shoulder, an axial length of the spigot portion being configured such that the annular surface is arranged to abut an annular end surface of a female end portion of a neighbouring rod of the drill string; and an outside diameter or width of the spigot portion including the shank and the helical ridge in a direction perpendicular to a longitudinal axis of the rod being equal to or more than the outside diameter of the main length section along a full axial length of the shank and the helical ridge.