Patent ID: 11947064
Assignee: SCHLUMBERGER TECHNOLOGY CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A method comprising:
disposing a toolstring in a cased portion of a borehole penetrating a subsurface formation, wherein the cased borehole portion comprises a metal casing, and wherein the toolstring comprises a module comprising a plurality of acoustic transducers distributed azimuthally around the toolstring and each operable to emit and receive acoustic signals;
operating the module to:
emit an acoustic signal, from at least one of the transducers, into fluid surrounding the module in the casing; and
record data indicative of receipt, by a plurality of the transducers, of acoustic waveforms resulting from interaction of the emitted acoustic signal with the casing, including at least a non-specular diffraction head wave excited by a guided wave that is excited by diffraction of the acoustic signal propagating in the casing metal; and

determining acoustic velocity of the guided wave in the casing metal (Vguided) utilizing the recorded data and geometric parameters of the module.