Thermo-mechanical modelling of progressing cavity pumps and positive displacement motors

The use of Progressing Cavity Pumps (PCPs) and Positive Displacement Motors (PDMs) in oilfield production and drilling capacities is widespread. Both types of machines consist of a steel rotor rotating within a mating elastomeric stator. Cyclic loading of the stator elastomer generates heat that causes the temperature of the elastomer to climb well above the environment temperature, sometimes resulting in failure or poor performance of the pump or motor unit.;An efficient, pseudo-steady-state thermo-mechanical modelling strategy for determining the stabilised downhole elastomer temperature and associated structural response in PCP and PDM stators is presented. Structural, heat generation, and thermal models form the basis for an iterative solution procedure that may be extended to any configuration of PCP or PDM. Full-scale testing using an instrumented stator shows that the modelling strategy provides a reasonable estimate of the stabilised operating temperature.