(2014007) A FULLY TRANSIENT ROD PUMP MODEL WITH HYDRAULIC DAMPING
Mathematical rod pump models are used in the design and optimization of lift systems. Most models are based on the damped wave equation, assuming steady state cyclic behavior and empirical damping factors. Such models cannot be used for fully transient analyses.
This paper extends the rod pump model based on fluid flow into he reservoir, wellbore and tubing. Rod drag is determined from multiphase flow modeling using the full momentum, mass and energy balance equations with friction loss terms based on standard pipe flow correlations. The effect of transient reservoir flow is incorporated by a radial flow reservoir model for inflow to the wellbore.
Development of the model is discussed and shown to predict complex system behavior. The model is then used to evaluate damping factor and suggest the potential for additional surveillance methods based on transient fluid and rod behavior.