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This is a method and apparatus for controlling an oil-well beam pumping unit in a manner which allows increased oil production. The AC electric motor of the beam pumping unit is supplied power through a variable frequency power supply, whose frequency (and voltage) is controlled by circuitry to auto

This is a method and apparatus for controlling an oil-well beam pumping unit in a manner which allows increased oil production. The AC electric motor of the beam pumping unit is supplied power through a variable frequency power supply, whose frequency (and voltage) is controlled by circuitry to automatically adjust to whatever flow enters the wellbore by varying the speed of the pumping unit to maintain the speed generally proportional to the real power consumed by the pump. As the level in the wellbore can be maintained at an essentially constant minimum level, despite the relatively large hour-to-hour variations in in-flow which normally occur, the total flow from the formation into the wellbore in a given period of time is increased.

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A variable pumping speed control system for a beam pumping unit in which a down-hole pump is actuated by a rod string driven by an AC motor, said system comprising: (a) means for generating a signal indicative of real power supplied to the pump; (b) means for generating a signal which is a function

A variable pumping speed control system for a beam pumping unit in which a down-hole pump is actuated by a rod string driven by an AC motor, said system comprising: (a) means for generating a signal indicative of real power supplied to the pump; (b) means for generating a signal which is a function of pumping speed; (c) a variable frequency power supply having a signal input, a power input and a power output, said power input being connectable to a source of AC power, and said power output adapted to be connected to said AC motor; and (d) control circuitry having inputs adapted to receive said real power signal and said speed signal and an output connected to said signal input of said variable frequency power supply, said control circuitry being adapted to vary the output of said variable frequency power supply to maintain said speed signal essentially directly proportional to said real power signal.