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Abstract When drilling wells with a narrow geo-pressure window, Managed Pressure Drilling (MPD) is often the most effective method to safely drill and complete the well. However, maintaining downhole pressure within the safe operational window requires precise control, especially in complex scenarios such as Extended Reach Drilling (ERD). Traditionally, MPD has focused on managing pressure during non-rotational phases, such as connections and stripping. However, it is essential to manage pressure throughout the entire drilling process—including during drilling, connections, downlinks, tripping, and stripping. In addition to pressure-related events, drilling dynamics such as torsional stick-slip, axial oscillations, and whirling must be considered, as they significantly affect downhole pressure stability and overall well success. Recent advances in downhole sensor technology now enable the recording of high-frequency (100 Hz) pressure data and ultra-high-frequency (1220 Hz) mechanical/dynamic data. These measurements have revealed previously unrecognized correlations between high-frequency mechanical movements and pressure fluctuations during drilling. This study presents data from several ERD wells drilled using MPD to maintain narrow pressure margins. In these cases, drilling dynamics—particularly stick-slip—were found to cause pressure variations of up to 8 bar, often pushing the downhole pressure outside the managed envelope. Periods of intense whirling were also recorded, showing high-frequency pressure fluctuations (around 40 Hz) with amplitudes frequently exceeding 15 bar. During stripping operations, even with constant backpressure, connection phases showed pressure drops of approximately 2 bar. These findings highlight the limitations of pressure control precision and underscore the importance of accounting for dynamic effects in MPD planning. Prior to the availability of high-frequency downhole measurements, the impact of drilling vibrations on pressure stability was not fully understood. Over the past decade, however, real-time high-resolution data have revealed that downhole conditions are far more complex than previously assumed. This insight is vital for improving our understanding of drilling dynamics and enhancing the likelihood of success in technically challenging wells. To further investigate the effect of pressure fluctuations on wellbore stability, time-lapse calliper tools were used to monitor hole size and shape during the drilling process. If, for example, the downhole pressure curve falls below the modelled collapse curve for an extended period and no hole collapse is observed, this can aid is calibrating the model.