Abstract: A method and apparatus for managing power demand of a motor in a cyclic load system having a rotational mass is provided. Flat power draw is achieved through continuous manipulation of the motor torque as a function of feedback velocity while using the rotational mass of the cyclic load as a means to store/retrieve energy. Alternatively, reduced variation of power draw is accomplished through continuous manipulation of motor velocity as a function of feedback torque. The methods and apparatus are used in systems where zero or reduced power demand variation is either required or desired, such as in generator powered applications.

Abstract: An apparatus and method for pumping fluids, such as water and/or hydrocarbons, from a subterranean formation or reservoir, include a linear rod pump having a mechanical rack and pinion drive arrangement, adapted for attachment to a pumping mechanism, such as the polished rod at the top of a rod string in a hydrocarbon well. The rack gear, of the rack and pinion drive arrangement, is adapted for connection to, and movement with, the polished rod. The pinion gear does not translate with the rack gear, and is driven by a reversible motor for affecting up and down reciprocating motion of the rack gear and pumping mechanism. Some forms of the invention include a compressible gas counter-balance arrangement. Some forms of the invention include an electronic drive configured for dealing with electric power generated by the motor during a portion of the pumping cycle.

Abstract: A rod pump control system includes a parameter estimator that determines from motor data parameters relating to operation of the rod pump and/or downhole dynamometer card without the need for external instrumentation, such as down hole sensors, rod load sensors, flow sensors, acoustic fluid level sensors, etc. In one embodiment, instantaneous motor current and voltage together with pump parameters are used in determining rod position and load. The rod position and load are used to control the operation of the rod pump to optimize the operation of the pump. Also disclosed in a pump stroke amplifier that is capable of increasing pump stroke without changing the overall pumping speed, or in the alternative, maintaining the well output with decreased overall pumping speed.

Abstract: A rod pump control system includes a parameter estimator that determines from motor data parameters relating to operation of the rod pump and/or downhole dynamometer card without the need for external instrumentation, such as down hole sensors, rod load sensors, flow sensors, acoustic fluid level sensors, etc. In one embodiment, instantaneous motor current and voltage together with pump parameters are used in determining rod position and load. The rod position and load are used to control the operation of the rod pump to optimize the operation of the pump. Also disclosed in a pump stroke amplifier that is capable of increasing pump stroke without changing the overall pumping speed, or in the alternative, maintaining the well output with decreased overall pumping speed.