Unlocking High-Temperature Drilling Performance in Remote Offshore: A Case Study of Novel Synthetic-Based Mud in Anambas Offshore Exploration Well

This paper outlines the successful implementation of an advanced synthetic-based mud (SBM) system for drilling the A-2X exploration well in a high-temperature, offshore remote environment. The well encountered bottomhole static temperatures (BHST) exceeding 365°F and so required stable fluid properties under extreme thermal and wellbore instability prone conditions. The objective is to highlight engineered SBM formulation, thermal resilience, wellbore stability performance, and best practices in fluid management, especially considering the complex logistics at the remote offshore area during pandemic situations. An innovative SBM formulation was developed to withstand high thermal loads while maintaining rheological stability, low filtrate loss, and minimal emulsion separation at temperatures exceeding 365°F. The thermal loads also give significant impact with cumulative temperature-induced degradation mechanisms to the Synthetic Based Mud system such as emulsion breakdown, chemical instability of additives, accelerated base-oil thinning, and post-circulation cooling effects on rheology. The mud system was subjected to HTHP testing, continuous thermal aging, and hydraulic simulation to validate its field resilience. Wellbore stability geomechanics modeling supported mud density selection, while real-time monitoring ensured optimal hole cleaning and ECD management. All critical mud additives, including temperature-stable emulsifiers and organoclays, were mobilized via tight offshore logistics to a remote offshore rig site in Anambas Field (Fig 1) during COVID restrictions, ensuring uninterrupted fluid maintenance throughout the well sections.