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Abstract Sonic logging is essential for seismic calibration, pore-pressure prediction, geomechanics assessment, gas detection, and wellbore stability analysis, particularly in ultra-deepwater environments. In riserless sections, logging-while-drilling (LWD) tools serve as a highly effective measurement platform. However, the reliable extraction of shear slowness remains a significant challenge, especially in slow and unconsolidated formations, which must be addressed to enhance analytical capabilities. This paper showcases field-proven results from multi-well applications of an azimuthal LWD sonic tool, integrated with advanced multi-mode dispersion processing using quadrupole excitation (AMDPQ). Operating in the frequency domain, this innovative methodology harnesses full-spectrum dispersion responses from quadrupole-generated screw waves. By constructing a differential phase frequency-slowness semblance map to capture vital dispersion trends, we transform these insights into slowness-density representations. Shear slowness is identified through edge-detection techniques and refined with dispersion-based auto-matching, leveraging adaptive frequency and slowness stretching. This study clearly demonstrates a significant operational advancement through the implementation of downlink-enabled firmware, which empowers real-time adjustments to tool firing sequences, acquisition parameters, and processing windows during drilling. This capability ensures proactive optimization of data acquisition in response to changing formation conditions, a necessity in riserless deepwater drilling where intervention is limited. Field deployments clearly demonstrate that the integration of AMDPQ processing with real-time tool control delivers exceptionally reliable shear slowness measurements, often exceeding 400 µs/ft, in formations where traditional methods falter. The results consistently align with wireline data from adjacent sections, affirming the accuracy of the approach. This study shows that LWD sonic measurements, empowered by real-time adaptability and advanced dispersion analysis, are the most effective solution for shear characterization in riserless ultra-deepwater intervals. This capability significantly enhances early formation evaluation and profoundly reduces drilling uncertainty.