Critical Gas Flow Rate Analysis for Mitigating Liquid Loading in the MnaziBay Gas Field, Tanzania.

Liquid loading is a prevalent production challenge in mature gas wells, occurring when declining reservoir pressure prevents sufficient gas flow from lifting co-produced liquids, leading to accumulation, increased backpressure, and potential well shut-in. This study investigates the minimum critical gas flow rate required to prevent liquid loading in the Mnazi Bay Gas Field, Mtwara, Tanzania, using Well MB#01 as a case study. Three approaches were employed: the empirical Turner et al. (1969) method, nodal analysis via PIPESIM, and wellbore-centric modeling with PROSPER. Turner’s model estimated a critical flow rate of approximately 14.96 MMSCFD, while PIPESIM predicted a minimum threshold of 3.8 MMSCFD, and PROSPER highlighted potential loading risks below 9 MMSCFPD. Current production levels indicate that MB#01 operates safely above these thresholds; however, ongoing reservoir pressure decline may increase the risk of liquid loading. Mitigation strategies, including surface compression, gas velocity strings, and multiple completions, are recommended to maintain safe flow rates and prolong well life. The study demonstrates that integrating empirical methods with simulation-based modeling provides a more accurate and practical framework for predicting critical flow rates and managing liquid loading in mature gas wells. These findings offer valuable insights for field operators in Tanzania and other Sub-Saharan gas-producing regions facing similar challenges.