Eccentric fluid displacement sleeve.

摘要

An eccentric fluid displacement sleeve (40',40'') is disclosed for use with a measurement-while-drilling instrument (10), to convert the instrument for use in different size boreholes. The sleeve is made eccentric by either increasing or decreasing the thicknesses of positioning blades (44',44'',46',46'') on the periphery of the sleeve, while maintaining the thickness of the fluid displacement blade (42',42'') aligned with the detectors (14,16).