Long-stroke pumping unit

A pumping unit to reciprocate a rod string for a downhole pump disposed in a well, the pumping unit comprising:

• a tower;
• a counterweight being movable along the tower;
• a belt disposed on the tower and being connected between the counterweight and the rod string;
• an electric motor configured to reciprocate the belt on the tower;
• a variable speed driver in electrical communication with the electric motor;
• a plurality of sensors configured to measure a plurality of sensor measurements, the senor measurements at least including a first position associated with the rod string, a force exerted on the rod string, and a power consumed by the electric motor;
• and
• a controller connected to the variable speed driver and the sensors, the controller being configured to:
• determine, for a pumping cycle, at least one parameter associated with operation of the downhole pump based on the sensor measurements;
• determine, for a subsequent pumping cycle, a prime objective associated with the operation of the downhole pump based on the at least one parameter;
• and
• control stroking of the pumping unit by the electric motor with the variable speed driver in the subsequent pumping cycle based on the prime objective.