Enhanced Casing Wear Assessment: A New Experimental Approach to Wear Factor Evaluation with Insights into Flow Regimes, Tool-Joint Materials, and Presence of Cuttings

Summary Severe casing wear during the drilling of complex, tortuous, and highly deviated well trajectories is a pressing issue, leading to casing wall thickness reduction and consequent tubular degrading. Addressing this problem requires experimental studies on controllable parameters in combination with theoretical tribology analysis. In this work, we investigate the key factors that affect casing wear, describe a closed-loop testing approach, introduce an alternative geometrical model for quantifying wear volume, and provide a more detailed prediction of contact-time-dependent wear depth supported by more granular casing wear factors. Our results show that a contact-time-dependent wear factor should be accounted for as one of the controlling parameters for nonlinear wear penetration. We further investigate the impact of fluid flow regimes on wear profiles under three-body abrasion (inclusive of cuttings), which is critical and has remained a relatively underexplored area. In addition, our work addresses the long-standing discussion on whether wear is more pronounced in water- or oil-based systems, drawing a direct comparison between the two. Finally, it was observed that wear is not uniformly distributed under three-body abrasion; depending on where cuttings accumulate (entry side), wear depth is significantly larger compared with the exit side of the annulus between the tool joint and casing, highlighting the need for a deeper understanding of localized wear mechanisms. The work undertaken in this project offers a closer look into wear factor selections and a framework that could help improve predictions and hence mitigate casing wear.