| 摘要 |
PCT No. PCT/GB94/02236 Sec. 371 Date Sep. 16, 1996 Sec. 102(e) Date Sep. 16, 1996 PCT Filed Oct. 12, 1994 PCT Pub. No. WO95/10685 PCT Pub. Date Apr. 20, 1995A drill pipe protector comprises an annular body (820) adapted to surround a drill pipe (824) in a borehole to protect the drill pipe and borehole (or borehole casing) against damage caused by contact between the two, such that the drill pipe may rotate freely within the annular body upon contact between the body and the borehole (or borehole casing), so as to reduce the torque and drag produced by such contact. The assembly may further include annular clamps (822) secured to the drill pipe (824) to restrict the longitudinal movement of the body along the pipe. Various features of such assemblies are disclosed including features of the shape and configuration of the annular body and clamps, the use of bearing members on the internal and external surfaces of the annular body and between the body and the clamps or drill pipe joints, and materials for use in the fabrication of the body and bearings. These are particularly concerned with optimising the bearing arrangements to promote thin film lubrication and to employ sacrificial self-lubrication when such thin film lubrication breaks down, configuring the assembly to promote fluid flow around and through the assembly and the avoidance of snagging of the assembly on downhole obstructions.
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