| 摘要 |
An automatic pump for deep wells comprises a long stroke reciprocating pump having its piston normally in its bottom position and an automatic control dependent upon the collection of a predetermined amount of liquid in the pump cylinder above the piston for actuating the piston to pump the liquid into a production line. The automatic control includes an electric motor driven hydraulic pump and a reservoir of hydraulic fluid which is actuated upon filling of the reciprocating pump chamber to supply hydraulic fluid to a closed chamber below the piston and force the piston upwardly to discharge liquid from the pump cylinder. Gas collected in the top of the pump cylinder results in low starting current and a saving of energy. The hydraulic pump is reversed automatically upon completion of the pumping stroke of the piston. The assembly may be inserted in a well casing on a wire line and positioned in the casing, a packer being provided between the assembly and the casing. When the assembly is to be removed, if the packer has become bonded to the casing, release may be facilitated by use of ultrasonic energy.
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