Progressing Cavity Pump with an Underground Drive

The installed centrifugal submersible pumps, pumpjacks, and progressing cavity pumps can handle local conditions, such as partially deflected boreholes, paraffin mixtures and sand mixtures with varying degrees of effectiveness. Progressing cavity pumps (PCP), as rotary positive displacement pumps, are suitable for particularly demanding media, both viscous and abrasive. However, the pumping rods, which are often up to 3000 meters long, may break, and the piping may wear through.To get more news about Progressive cavity pump part, you can visit brysonpump.com official website.

In comparison, submersible centrifugal pumps do not have pump rods, but they are not very suitable for fluids that contain sand and/or gas. In an effort to reduce the number of pumping installations, the oil field operator has begun to look for an efficient and durable system capable of combining the advantages of both types of pump: a system that combines a submersible motor of a submersible centrifugal pump with a progressing cavity pump. The systems available on the market so far were out of the question, since they are equipped with a planetary gear system that is highly error-prone. The company finally decided in favour of a solution developed by NETZSCH Pumpen Systeme GmbH in Waldkraiburg, which does not use this vulnerable component. It is a progressive cavity pump (PCP) system with underground drive and a permanent magnet motor (PMM). Even with the difficult media described above, it allows higher flow rates than the previously used units. It also lowers operating costs thanks to its lower failure rate.

The company uses three different pump types for conveying operations on its crude oil fields south of Bremen. Due to their different design and functions, the different models work with varying degrees of effectiveness in the specific conditions of production wells. “Each type of pump has specific advantages and disadvantages,” explains Jörg Eitler, Global Business Field Manager for Oil Gas Upstream at NETZSCH. “For example, in the case of pumpjacks and progressing cavity pumps, pump rod fractures occur relatively frequently. Since the rods move constantly during extraction, tubes may become damaged. This is more likely the further the borehole path deviates from the vertical position.” As a result, time-consuming work may be required to repair the damage and resume production. In the case of submersible centrifugal pumps, this risk is much lower. They must be very precisely designed and carefully installed to avoid damaging the underground cable during installation, especially if the borehole path is not vertical. However, once the installation is successfully completed, the cables often have a much longer service life than the rods of progressing cavity pumps and pumpjacks. This is because the cable is not under dynamic load during operation, as is the case with pump rods.

The decision makers considered a combination of progressing cavity pump and submersible centrifugal pump, which combines the advantages of both pump types, to be particularly useful and efficient for the applications in the North German oil fields. What’s more, pumps of this kind have already been developed and assembled. These are the so-called rodless PCP (progressive cavity pumps) or ESPCP (electric submersible progressive cavity pumps) – progressing cavity pumps driven by a submersible motor. Based on the advice from oil field specialists, the company decided on a special model developed by NETZSCH Pumpen Systeme GmbH, which does not require a transmission ratio between the motor revolutions and the pump, since the motor selected specifically for this application can be operated at very low frequency. In addition to the progressing cavity pump, the system consists of a permanent magnet motor, sensors, motor protector, bearing unit and a flexible rod, called FlexShaft. Other components are a check valve, a drain valve and a cable that is used to power the motor and to transfer data from the sensor.