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U.S. Department of Energy
Office of Scientific and Technical Information

In-casing hydraulic jack system

Patent ·
OSTI ID:6849165
An in-casing hydraulic jack system for operating well bottom pumping units via a sucker rod string and polish rod is described, comprising a jack unit having a hydraulic cylinder with top and bottom ends and a piston positioned for reciprocation within the hydraulic cylinder, mounting means connected to the jack unit for suspending the jack unit fully within a well casing, sealing means carried by the jack unit for producing a seal between the jack unit and the interior of the well casing, connecting means at the bottom end of the hydraulic cylinder for connecting the jack unit to a top end of a well fluid delivery tubing, attaching means for attaching a top end of a polish rod to the piston of the jack unit so as to be displaceable in conjunction therewith and access means disposed above the jack unit for enabling insertion and removal of the polish rod while the jack unit is suspended in the well casing. There are also hydraulic fluid supply means connected to the hydraulic cylinder for producing reciprocation of the piston within the cylinder by delivery of hydraulic fluid to the hydraulic cylinder in a manner to as to produce an upward stroking of the polish rod, and discharge means in the jack unit for enabling well fluid delivered by the well fluid delivery tubing to bypass the sealing means so as to be discharged from the well casing at a location above the seal means.
Assignee:
NOV; EDB-88-153277; NOV-88-023361
Patent Number(s):
US 4745969
OSTI ID:
6849165
Country of Publication:
United States
Language:
English

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