Patent ID: 8863834

Claim:
A method of reducing friction between a tubular string and a bore, comprising: receiving a first sleeve bearing having a first longitudinal end to slidably engage a first interior shoulder within a first bore portion of a rotating element; receiving a second sleeve bearing having a first longitudinal end to slidably engage a second interior shoulder within a second bore portion of the rotating element; receiving the rotating element and the first and second sleeve bearings onto a tubular segment; receiving a first stop collar, having a first longitudinal end onto the tubular segment, wherein the first stop collar first longitudinal end contacts a second longitudinal end of the first sleeve bearing, preventing an external shoulder of the first stop collar from contacting a first axial end of the rotating element; receiving a second stop collar, having a first longitudinal end onto the tubular segment opposite the first stop collar, such that the first stop collar and the second stop collar together straddle the first and second sleeve bearings, wherein the second stop collar first longitudinal end contacts a second longitudinal end of the second sleeve bearing, preventing an external shoulder of the second stop collar from contacting a second axial end of the rotating element; and securing the first and second stop collars to the tubular segment, wherein the tubular segment is rotatable relative to the rotating element and is configured to be disposed in the bore as part of the tubular string.