Boundary Conditions Used With Dynamic Models Of Beam Pump Performance

Several studies have appeared in the literature concerning details of dynamic models of beam pump and rod string performance. Many of these studies deal with the equations and models presented by S. G. Gibbs.*-" Also, some other work has indicated techniques of modeling and solutions to governing equations. An equation is developed here which is used to generate a "diagnostic" and a "design" type of beam pump analysis program. The equations needed at the interface of rods of different properties are presented and discussed. This method allows an explicit statement of the equal force boundary condition at the interface of rods of different properties. No averaging of properties is required across the interface. Also, any change in the speed of sound from one rod to another is accounted for.