Corrosion inhibitors in drilling mud: Advances, challenges, and future Directions

Corrosion remains a persistent challenge in drilling operations, particularly under high-pressure, high-temperature (HPHT) conditions, resulting in economic losses and safety risks. While conventional corrosion inhibitors have been effective to varying extents, their limitations, particularly in terms of toxicity, biodegradability, and compatibility with drilling fluid properties, necessitate exploring sustainable alternatives. Recent advances have focused on green inhibitors, notably plant-derived extracts, due to their biodegradability and low toxicity. However, a critical gap remains: few studies holistically evaluate both corrosion inhibition efficiency and the resultant impact on drilling fluid performance. To address this, the present review introduces an Integrated Screening and Corrosion Inhibition Modelling (I-SCIM) framework. This review comprehensively synthesizes recent research on corrosion inhibitors used in water-based, oil-based, and synthetic-based fluids. It categorizes inhibitors, evaluates their performance, and discusses their integration into complex mud systems. Key findings highlight that while conventional inhibitors achieve 70–85% efficiency, emerging green and hybrid formulations often exceed 90% inhibition. Furthermore, the paper explores the emerging class of smart and responsive inhibitors that adapt to environmental stimuli such as pH and temperature, highlighting their potential in dynamic wellbore conditions. By adopting the I-SCIM framework, this paper bridges the fragmented assessment approaches in current literature and proposes a unified strategy for evaluating corrosion inhibitors beyond inhibition efficiency alone. The review culminates in future research recommendations for inhibitors that are sustainable, efficient, and compatible with the evolving demands of HPHT drilling.