Paul Bradley Rhodes
Engineering at Omeara Dr, Houston, TX

5089989, Feb 18, 1992

Oct 30, 1990

7/609026

Mathew G. Schmidt - Houston TX
Peter C. Masak - Katy TX
Paul B. Rhodes - Houston TX

Western Atlas International, Inc.

G01N 904, G01V 140

367 35

A new "radial" cement bond instrument is disclosed for measuring the quality of cement to casing bond. The instrument is capable of measuring the quality of the cement bond both vertically and circumferentially. Four arrays of sectored transmitters and receivers are arranged longitudinally along the instrument body and provide a compensated radial bond measurement with high azimuthal resolution. The sectored transmitter excites both a compressional wave and a shear wave in the casing, with the beam pattern of the transmitter focused in a radial direction. The sectored receiver provides additional directivity for enhanced detection of channels in cement. The disclosed apparatus provides measurement of the quality of cement bond in eight radial segments. The resolution of the instrument provides 5 to 10 percent overlap to insure "full" coverage of the borehole. In its normal operational mode, amplitude information is recorded from the sectored receivers, an acoustic signature from a five-ft spaced transmitter-receiver is recorded, and a two-axis orientation measurement is acquired.