Research on the Mechanical Behavior of the Heavy-Load Suspension Slip With Variable Tooth Height for the Liner in Ultradeep Wells

Summary Large-sized, ultralong, overweight liners are critical components of ultradeep wellbore structures, with liner hanging technology serving as the key method to overcome rig load limits. However, under heavy-load working conditions, stress concentration at the front contact area between hanging slips and casings severely impairs hanging capacity. In this study, we analyze the mechanism of stress concentration and propose a variable-tooth-height heavy-duty hanging slip. Using elastoplastic multibody contact dynamics, a 3D finite element model was developed to investigate key structural parameters. Results show that the variable-tooth-height design reduces front tooth stress, enhances rear tooth casing contact, equalizes tooth loading, and mitigates casing damage. Optimization achieves an 8.7% reduction in average stress on the upper casing inner wall, a 45.5% decrease in casing plastic strain, and increases yield state teeth from 5 to 13. This work provides theoretical support for heavy-load-liner hanging mechanisms in ultradeep wells.