الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The Progressing Cavity Pump was a success story from the start. Integrating a new concept and patented invention, it was rapidly adopted throughout the industry for transferring many types of fluid. During the 1980s, progressing cavity pumps started to be used to lift oil wells and are used worldwide today. PC pumps have developed their own unique line of products. As a result, each manufacturer of At present, there are several different manufacturers which produce more than one hundred distinct downhole PC pump geometries. When combined with variations in rotor and stator materials, this results in an enormous array of different pump models. Bench tests are used to quantify the performance characteristics of new and used PC pumps. In the case of a new pump, the test results are used to appropriately ”size” the pump (i.e. match the rotor and stator to obtain a specified ”fit” or volumetric efficiency at the rated pressure of the pump) for its intended application. Tests are completed on used pumps to establish their suitability for reuse or to help identify the mechanisms that may have led to its failure. Proper testing and sizing is essential to ensure that a pump will operate effectively downhole. In general, volumetric efficiency always decreases with increasing pressure. This decrease is due to fluid slippage, which can be defined as the leakage of fluid across the rotor/stator seal line from higher to lower pressure cavities. The larger the pressure differential between two adjacent cavities, the higher the slippage rate will be across the intermediate seal line.