Study on the mechanism of drill string uplift during emergency shut-in of blowout preventer

To clarify the mechanism of drill string uplift during emergency blowout preventer (BOP) shut-in, integrated theoretical mechanics and finite element simulation models were established. Results indicate that while uplift force trends remain consistent regardless of internal BOP presence, drill strings without internal tools exhibit significantly higher uplift speeds. Sensitivity analysis reveals that increasing drill string length, fluid density, or clamping force mitigates uplift risks; conversely, higher uplift speeds, friction coefficients, and drill string dimensions enhance both peak and stable clamping forces. This study characterizes the dynamic drill string-BOP interaction and proposes anti-uplift criteria, providing theoretical support for well-control hazard warning and emergency response optimization.