Friction-reducing drill pipe component

A friction-reducing drill pipe component for forming part of a drill string, the component comprising a tubular mandrel having first and second ends for connection to adjacent components of a drill string, a sleeve mounted on the mandrel, and spring-mounted lock dogs mounted on the mandrel and operatively associated with the sleeve for releasably retaining the sleeve on the mandrel, the released sleeve being removable over the first end of the mandrel.

A friction-reducing drill pipe component for forming part of a drill string, the component comprising a unitary tubular mandrel having first and second ends for connection to adjacent components of a drill string, a sleeve directly mounted on the mandrel, first and second stops on the mandrel for restraining the sleeve against axial movement relative to the mandrel, at least the first stop being moveable to a retracted position while being retained on the mandrel, wherein an outermost diameter described by the first stop in the retracted position and the mandrel in combination is less than an inner diameter of the sleeve to permit the sleeve to be removed from the mandrel, the sleeve being rotatable relative to the mandrel, and the sleeve and the mandrel each defining plane bearing surfaces.

A friction-reducing drill pipe component for forming part of a drill string, the component comprising a tubular mandrel having first and second ends for connection to adjacent components of a drill string, a sleeve mounted on the mandrel, and first and second stops on the mandrel, intermediate the first and second ends, for restraining the sleeve against axial movement relative to the mandrel, at least the first stop being movable to a retractable position wherein an outermost diameter described by the first stop in the non-operative position and the mandrel in combination is less than an inner diameter of the sleeve to permit the sleeve to be removed over the first end of the mandrel, and wherein the sleeve is rotatable relative to the mandrel and bearings are introduced into a gap between the sleeve and the mandrel through a port in the sleeve.

A friction-reducing drill pipe component for forming part of a drill string, the component comprising a tubular mandrel having first and second ends for connection to adjacent components of a drill string, a sleeve mounted on the mandrel, and first and second stops on the mandrel, intermediate the first and second ends, for restraining the sleeve against axial movement relative to the mandrel, at least the first stop being movable to a retractable position wherein an outermost diameter described by the first stop in the non-operative position and the mandrel in combination is less than an inner diameter of the sleeve to permit the sleeve to be removed over the first end of the mandrel, and at least one opening is provided in one of the sleeve and mandrel to permit drilling fluid in the bore to enter a gap between the sleeve and mandrel and serve as a lubricant therebetween.

A friction-reducing drill pipe component for forming part of a drill string, the component comprising a tubular mandrel having first and second ends for connection to adjacent components of a drill string, a sleeve mounted on the mandrel, and first and second stops on the mandrel, intermediate the first and second ends, for restraining the sleeve against axial movement relative to the mandrel, at least the first stop being movable to a retracted position wherein an outermost diameter described by the first stop in the retracted position and the mandrel in combination is less than an inner diameter of the sleeve to permit the sleeve to be removed over the first end of the mandrel, wherein the first stop is in the form of a collar retained on the mandrel by retractable connectors.