| 摘要 |
The invention relates to an oil well comprising a production tubular with a pump barrel attached to its lower end, a reciprocable oil pump having a plunger located within the pump barrel, a sucker rod string extending downwardly from ground level to the plunger for reciprocating the plunger, means for cyclically raising the sucker rod string, a chamber located and arranged so as to be open to oil pressure immediately above the plunger, wherein the chamber is located externally of the production tubular, the chamber is in communication with the interior of the production tubular and the chamber contains a resilient bladder member arranged to occupy normally substantially the whole volume of the chamber to be connected to a source of pressurized gas through a non-return valve, to contain and maintain gas at the static oil pressure and to occupy a reduced volume of the chamber when the oil pressure immediately above the plunger increases due to pressure surges arising from elastic deformation of a column of oil.
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