Abstract: A control system governs fluid level in a well system including a pump positioned downhole for pumping fluid upward through a tubular, a rod positioned within the tubular for driving the pump, a prime mover, and a pumpjack to transmit power from the prime mover to the rod to reciprocate the rod. A sensor senses a position of the rod or a member of the pumpjack and outputting signals in response thereto. A controller receives the signals and computes a plurality of time intervals, each time interval being between signals and occurring during at least a portion of an upstroke of the rod. The controller selectively decreases power output from the prime mover in response to an increase in the computed time interval.

Abstract: A control system controls a progressive cavity pump driven by a rod. The rod is powered by a prime mover, such as a variable speed drive. A proximity sensor outputs signals responsive to rotational positioning of the rod. A controller receives the signals and computes a time interval between selected signals corresponding to a selected number of rod rotations. The controller references a data set, compares the computed time interval with the data set, and selectively increases, decreases, or cycles power to the prime mover in response thereto, thereby controlling the fluid level within the well.