Finite Element Analysis on Influence of Carburizing Layer Depth of Slips on the Occlusal Behavior and Damage Degree of Casing

The slip is a critical component of the packer, ensuring stable sealing performance under high differential pressure conditions. To enhance the surface hardness and enable more effective engagement with the casing during the setting process, carburizing treatment is commonly applied. However, studies on the interaction mechanism between the slip and the casing, particularly concerning the effect of carburized layer depth, remain limited. In this work, a coupled finite element analysis (FEA) model of the slip–carburized layer–casing system was developed to model carburized layers of varying depths on the slip surface. The model was used to systematically investigate the influence of carburized layer depth on casing engagement behavior and damage evolution. Simulation results show that the central region of the slip teeth is more prone to local collapse under setting loads. The equivalent stress within the casing decreases radially from the inner wall to the outer wall. Carburized layer depth significantly affects casing damage, the depth of the stress attenuation zone within the casing first decreases and then increases as the carburized depth increases from 0.6 mm to 0.9 mm. When the carburized layer depth is 0.7 mm, the damage of casing is minimized, with a sharp drop in equivalent stress occurring approximately 3 mm from the inner wall and a slower decline observed beyond 6 mm, indicating optimal structural compatibility. Furthermore, adopting a setting mechanism in which the upper and lower cones move synchronously in opposite directions enhances anchoring performance and further reduces the risk of casing damage. This study provides a theoretical basis for the optimized design of the depth of the carburizing layer of the slips, which is an important engineering reference value for improving the integrity of the pipe column and extending its service life.