WELL PUMPING UNIT Russian patent published in 2001 - IPC

FIELD: manufacture of pumps; oil production industry; operation of vertical inclined directional wells, marginal wells in particular at complicated characteristics of oil stratum. SUBSTANCE: well pumping unit is provided with flexible shaft. Tubing string is provided with seal (contact seal, for example) in its upper portion and with cap in its lower portion. Electric motor is located on earth surface at wellhead; power pump, hydraulic motor and working pump are located in cap of tubing string; power drive and hydraulic motor are combined in common unit; flexible shaft is located in tubing string between electric motor and power pump for passage through seal. Electric motor is provided with converter for control of rotational speed. EFFECT: enhanced operational reliability and increased service life of equipment. 2 cl, 1 dwg