Abstract
Casing removal operations in oil and gas wells, particularly during the critical processes of Plug and Abandonment (P&A) and subsea slot recovery, frequently encounter significant challenges due to the presence of settled barite in the annulus. This accumulation of barite, which is a heavy mineral used in drilling fluids to control pressure and stabilize the wellbore, can lead to a considerable increase in the pulling force required to remove the casing. As a result, operators often face higher operational costs and extended intervention times, which can affect overall project timelines and budgets. In response to these challenges, this study presents a novel and innovative approach aimed at effectively reducing the pipe pulling force required during casing removal operations. The proposed method involves the introduction of strategically placed holes above the casing collar, which serves a critical function by allowing the barite debris to escape into the borehole. This design modification not only facilitates the removal of accumulated barite but also helps in alleviating the excessive forces that would otherwise be necessary to extract the casing. To validate this approach, a downscaled experimental setup was meticulously designed to mimic the conditions associated with settled barite in the annulus. Through this experimental framework, pulling force measurements were conducted under a variety of scenarios to assess the effectiveness of the hole placements. In addition to the experimental work, comprehensive numerical analysis was carried out to optimize various parameters, including the placement, size, and number of holes, all while ensuring the integrity of the casing is maintained throughout the process. The results of the study are promising, demonstrating a substantial reduction in the pulling force required when the strategically placed holes are introduced. This reduction not only indicates a more efficient approach to casing removal but also suggests a pathway towards more cost-effective operations in the field. By addressing the issue of settled barite and enhancing the removal process, this innovative solution offers significant potential benefits for operators engaged in P&A and subsea slot recovery activities, ultimately contributing to the overall efficiency and effectiveness of oil and gas well abandonment operations.