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The gas sector in Indonesia holds significant importance for the economic and social well-being of the country. However, with the majority of large gas fields in Indonesia now in the mature stage, where a substantial portion of the recoverable gas volume has already been extracted, new challenges arise. One of the prominent issues faced by mature gas wells is the phenomenon of liquid loading, which significantly restricts gas production. In some cases, losses attributed to liquid loading account for as much as 30% of the total production. Therefore, it becomes crucial to address this issue to maximize the productivity of mature gas wells. To mitigate the impact of liquid loading, various technologies and methods are available, with surfactant injection, particularly foam injection, emerging as a cost-effective solution. Foam agents serve as foaming agents, facilitating the removal of liquids from gas wells. The effectiveness of foam injection is influenced by several factors, including the gas production rate, gas-liquid ratio, and dosage of surfactant (concentration of foaming agent). Optimal foam concentration is crucial for achieving efficient liquid removal and enhancing gas production. To address liquid loading challenges, it is imperative to conduct a deliquification implementation study before a gas field reaches its mature or declining stage. Early identification of liquid loading issues allows for timely interventions to mitigate the problem, ensuring continuous production and preventing well shut-in. This research aims to investigate the behaviour of mature gas wells and identify the optimal timing for intervention to address liquid loading. The study will analyze the impact of foam injection as an intervention method and perform a sensitivity analysis on varying surfactant concentrations to determine their effectiveness in mitigating liquid loading issues. Through gaining insights into the behaviour of mature wells and determining the ideal foam concentration, this research seeks to contribute to the development of strategies for effectively addressing liquid loading challenges in gas wells. Based on the findings of this study, the presence of liquid loading in the gas wells analysed was confirmed, with increased water production and decreased gas production. The calculations demonstrated that the existing condition of the well indicates an inability to remove the accumulated liquid without intervention, leading to the current shut-in status. Increasing the foam concentration showed promising results, reducing the minimum rate of liquid loading and increasing the production rate. Foam injection has emerged as an effective and costefficient method for liquid removal.