Simulation of single-phase liquid flow in Progressing Cavity Pump

Abstract

Progressing Cavity Pump (PCP), also known as Moineau pump, is an artificial lift method often used for pumping high viscosity and high solids content fluids from producing wells. Although, PCP has been effectively adopted in oil industry for decades, there is a lack of understanding the effect of its design parameters and operating conditions on the pump performance. The objectives of this study are to develop a model for predicting an actual multi-lobe PCP performance, and to investigate pump performance through simulating single-phase liquid flow behavior. The proposed model is a combination of two existing models in the literature, namely an analytical model to predict the theoretical pump performance, and a slippage model. The proposed model can be used not only to predict the actual multi-lobe PCP performance, but also to optimize pump design under given operating conditions. To validate the modeling results, an experimental study was carried out using a commercial PCP. The experiments were conducted with liquid viscosities ranging from 0 to 450cp, rotational speeds ranging from 0 to 300RPM, and pump differential pressures ranging from 0 to 300psi. The validation study revealed satisfactory results and reasonable match between the model predictions and experimental results. Using the developed model, an extensive sensitivity analysis was performed, which suggested that higher viscosity, in most of cases, minimizes pump slippage. In addition, if the pump clearance is smaller than a specific value, then the effects of differential pressure and liquid viscosity on the pump performance are minimal. Similarly, if the pump clearance is less than a specific value, then a pump with higher stator lobe number will deliver higher actual pump rate. The results of this study are not only important for manufacturers to optimize PCP design, but also for operators to improve PCP operational pump performance and pump efficiency.