Downhole Backspin Retarder for Progressive Cavity Pump

A backspin retarder for a progressive cavity pump having a drive string, the retarder comprising:

• a shaft disposing downhole and connecting to rotation of the drive string for the progressive cavity pump;
• and
• an impeller disposed on the shaft,
• the impeller having a disengaged condition and being rotatable relative to the shaft at least when the shaft rotates in a drive direction, and
• the impeller having an engaged condition and being rotatable with the shaft at least when the shaft stops rotating in the drive direction.

A progressive cavity pump, comprising:

• a drive;
• a pump unit deploying downhole of the drive and coupling thereto by a drive string;
• and
• a retarder deploying downhole and coupling to rotation of the drive string, the retarder permitting the rotation of the drive string relative to the retarder at least when the drive string rotates in a drive direction, the retarder retarding backspin rotation of the drive string at least when the drive string stops rotating in the drive direction.

A progressive cavity pumping method, comprising:

• lifting fluid in a tubing string by rotating a downhole pump unit with a drive string in a drive direction;
• disengaging a retarder from the rotation of the drive string at least when the drive string rotates in the drive direction;
• and
• retarding backspin of the drive string at least when the drive string stops rotating in the drive direction by engaging the retarder to the rotation of the drive string and producing drag with the retarder against the fluid in the tubing string.