Novel Fresh Water-Based Mud System in Highly Reactive Shale Formation: Experimental and Case Studies

Abstract

Abstract This paper investigates a novel water-based mud (NWBM) system for drilling in reactive shale formations. Laboratory experiments were conducted to evaluate the performance of NWBM with the Novel Polymeric Additive (NPA). Tests measured rheology, shale swelling, and high temperature/high pressure (HTHP) filtration loss. The results showed that NWBM with NPA significantly reduced mud filtration loss by over 78% compared to traditional water-based mud (TWBM). It also inhibited shale swelling by 40% and increased the rate of penetration by 28%. A case study in Bahrain demonstrated the successful field application of NWBM in reactive anhydrite formations. Despite wellbore stability challenges, the NWBM system enabled faster drilling with zero non-productive time (NPT). This research indicates that NWBM with NPA is a promising drilling fluid for reactive shale drilling. It can enhance drilling performance, reduce risks, and achieve operational efficiency. Further work is needed to optimize NWBM formulations for specific shale plays and evaluate environmental impacts. Field trials in different shale formations will help demonstrate the technology. This study provides a comprehensive overview of NWBM for drilling in reactive shales. The fluid system has great potential to overcome issues like wellbore instability, fluid loss, and NPT in challenging shale wells.