Closing the Water Loop in Under Balance Coiled Tubing Operations

Abstract This paper reviews the implementation of Closed Loop Drilling (CLD) in Under Balanced Coiled Tubing Drilling (UBCTD). It highlights the methods, results, and lessons learned during the project execution. The aim is to showcase the feasibility and benefits of combining CLD with UBCTD. Literature reviews and case studies identified best practices and potential pitfalls. Pre-job planning included risk assessments. Monitoring and control systems ensured optimal drilling parameters. KPIs were tracked to measure success. A multi-component process for separating solids, removing H2S, and maintaining drilling fluids’ operational limits was developed and implemented, enabling efficient handling of drill cuttings and fluids to increase recycling and reuse. Implementing CLD in UBCTD significantly reduced chemical consumption and water usage. Due to optimized drilling fluids and recycling, chemical consumption decreased by 70% for lubricant chemicals and 90% for H2S control chemicals. Water usage decreased by 97%, minimizing the footprint; the savings mentioned above have also been associated with the reduction of Scope-3 carbon emissions. The absence of a dedicated water pit benefited well site construction and reclamation efforts. Other benefits include hole stability and wellbore quality due to maintaining the drilling fluids’ properties with recycling. This study documents one of the first instances of applying CLD principles to UBCTD operations. Sharing the methodology, results, and learnings expands the understanding of CLD applicability beyond conventional drilling environments. Insights gained from this experience can guide future projects adopting similar sustainable drilling practices