Performance Evaluation of the Types of Polymers Used as Water-Based Mud Viscosifiers for Drilling Operations in Elevated Temperature Environment

The rising demand for energy resources pushes drilling operations into increasingly challenging environments, prompting the need for efficient and environmentally friendly drilling fluid formulations. This study investigates the performance of three commonly used polymers: starch (natural), carboxymethyl cellulose – CMC (modified) and partially hydrolyzed polyacrylamide – PHPA (synthetic) as viscosifiers/fluid loss additives in water-based drilling muds at elevated temperatures (80°C – 160°oC). Results revealed a nuanced interplay between temperature and mud performance. All polymers exhibited decreased rheological properties with increasing temperature, with starch mud showcasing the highest overall viscosity but a significant drop in yield point. Gel strength analysis showed PHPA mud excelling in cuttings suspension due to its superior cross-linking ability. The lowest fluid loss was observed in starch mud, suggesting its potential for better wellbore stability. However, environmental considerations favor starch due to its biodegradability, while higher cost and persistent nature pose challenges for PHPA and CMC, respectively. This study highlights the importance of tailoring drilling mud formulations to specific temperature profiles and wellbore requirements. Each polymer offers unique advantages and disadvantages, requiring careful consideration of rheological behavior, fluid loss control, and environmental impact for optimal drilling performance in high-temperature conditions.