PUMP ROD REPAIR METHOD Russian patent published in 2009 - IPC E21B17/00 B23P6/00 

FIELD: oil and gas industry.

SUBSTANCE: present invention is concerned with oil production, namely technique of pump rod repair. Pump rods are used for transmission of running in rod strings from surface drive unit to oil well pump and working in conditions of wearing and corrosion-fatigue failure. Repair method of pump rods that consist of body and threaded heads on both ends includes removal of defected areas, their replacement, connection of new areas by welding, preliminary treatment of surfaces and joints to the required area sizes, heat treatment and finishing of surfaces and joints to the nominal area sizes with necessary finishing. Before welding open hollow centers should be done on all areas including new ones on pump rod body, if there none. After surface finishing a bar, pre-strained by tension, is put through hollow center. The ends of the bar are fixed at rod ends. Thus, suggested repair method of pump rods permits to settle the problem of total restoration of original features and get some additional technical-economic properties.

EFFECT: reduction of deformation regarding the influence of service loads that allow increasing the efficiency of bottom-hole pump machine with other equal parameters; increase of utilisation factor of defected pump rods via maximum recycling of defect-free areas of pump rod bodies.