Startup torque dynamic model of single progressive cavity pump in surface-driven pumping system

Key words:  single progressive cavity pump  startup torque  dynamic model  pumping rod  imperfect elastic collision

Abstract:

Startup torque model of single progressive cavity pump in surface-driven pumping system is the theory base of improving system efficiency of progressive cavity pump well and conducting fault diagnosis. Performance characteristic and stress condition were analyzed in the process of progressive cavity pump well startup and a startup torque dynamic model was established. Contact collision between pumping rod and tubing was considered by the classical collision theory, and the kinematics and kinetic parameters of the whole pumping rod could be calculated by this model. Application of this model in Er-lian Oilfield shows that those torque curves along the well bore sway on both sides of the rod torque curve at stabilization. Prolonging the startup time can reduce the peak value of startup torque. Then the rod breaking problem due to oversize rod torque can be effectively solved while progressive cavity pump instantaneously started up.