Sonic logs provide key data for seismic velocity models and have application in a broad range of drilling, completions and production challenges related to rock deformation. A new small diameter wireline-style sonic logging tool with memory capability reduces acquisition risk and extends the application of data into wells that are technically or commercially challenging for conventionally-sized tools (such as slim and/or high dogleg severity wells, and wells where logging out of drill pipe may be the only cost-effective evaluation option). Innovations in the design of the flexural wave transmitter, acoustic attenuator and receiver assemblies allow compressional and shear velocities and shear anisotropy to be determined from a uniquely small package that is not constrained by wireline data transmission rates (and can therefore be combined with the micro-resistivity imager and other high data density tools without compromising logging speed).

Performance is reviewed from operations around the world. Logs from shallow and deep reservoirs, including both conventional and unconventional reservoirs, demonstrate the robustness of the data over a broad range of common environments. The ability to accurately characterize slow formations (including from enlarged borehole intervals) is demonstrated, and minimum horizontal stress orientations inferred from the tool are shown to be consistent with independent analysis from image log data.

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