Abstract A new methodology for evaluating the risk of gun jump during post-perforating surge is proposed and tested against field data. This methodology is corroborated by an advanced mathematical model of transient flow into the wellbore triggered by the creation of perforation tunnels under static underbalance and fully coupled with evolving transient flow inside the wellbore containing the gun string. The model predicts the viscous drag on the tool string and the gun string dynamics, which may induce cable tangling or breaking owing to gun jump. This model is used to mitigate the risk of gun jump by varying perforating job design options such as shot density, thickness of the perforated interval, and height of the liquid cushion. Examples of model application to the analysis of field data from Indonesia are provided.