Control apparatus and method for controlling the rate of liquid removal from a gas or oil well with a progressive cavity pump

摘要

A method and apparatus for controlling the level efficiently, and rate of removal of water from an oil or gas well using a progressive cavity pump operated by a rotating drive shaft extending downwardly from ground level to the pump comprises a sensor that detects the downward force on the shaft produced by the dynamic operation of the pump; and a control mechanism responsive to the output from the sensor that correlates the downward force on the pump with liquid depth in the casing and controls pump speed in order to achieve a desired rate of liquid removal from the casing and a desired ultimate depth level of liquid in the casing above the pump. A novel fluid pressure sensing mechanism mounted on the shaft at ground level permits the shaft to rotate while providing an accurate reading of the downward force on the shaft. Computerized controls receive the pressure signals from the sensing mechanism and control the rate of operation of the pump motor in order to achieve a desired rate of pump operation to efficiently produce a desired rate of pump down and a desired liquid depth in the casing. Preferably, all of these elements are installed and maintained above ground.