Paper: Selecting A Progressive Cavity Pumping System

The Progressive Cavity (PC) Pump is being used in various types of applications worldwide, particularly because of its simplicity of operation and increased mechanical efficiency over other methods of artificial lift. As with all fluid lift methods, the proper selection of the pumping system's size and materials of construction is most important to ensure increased operating life and overall efficiency. The selection process for a pc pump system is relatively easy due its simple design. The down hole pump consists of only two parts: the single helix rotor and the double helix stator. See figure 1. The rotor is normally alloy steel machined to an exact tolerance and chrome plated. The stator consists of a steel tube into which an elastomer is injected and chemically bonded. The selection process involves selecting the rotor base metal with the type of plating or coating and the stator elastomer type. Included in the following text is a step-by step procedure for sizing a PC pump system including selecting: a pump model based on production rates, pressure and fluid characteristics; the rod string size and grade based on proven combined stress calculations and well conditions; the surface drive system based on the pump and rod size; and specific ancillary equipment.