Progressing cavity pump control using pump fillage with PID based controller

A method of controlling operation of a positive displacement pump at an oil and gas well, comprising:

• obtaining, at a pump control system, a current fluid flow rate for fluids being produced from the oil and gas well, the fluids being pumped from the oil and gas well by the positive displacement pump;
• obtaining, at the pump control system, a current pump speed for the positive displacement pump, the current pump speed corresponding to the current fluid flow rate for fluids being pumped from the oil and gas well by the positive displacement pump;
• calculating, at the pump control system, a theoretical fluid flow rate based on the current pump speed and one or more pump characteristics;
• calculating, at the pump control system, a pump fillage based on the theoretical fluid flow rate and the current fluid flow rate;
• comparing, at the pump control system, the calculated pump fillage to a target pump fillage using a pump control algorithm and one or more tuning parameters;
• generating, at the pump control system, a corrected pump speed using the pump control algorithm and the one or more tuning parameters;
• and
• controlling, at the pump control system, a motor speed of the positive displacement pump using the corrected pump speed to optimize production of fluids from the oil and gas well while minimizing wear on the positive displacement pump.

A computer-readable medium comprising computer-readable instructions for causing a controller to:

• obtain a current fluid flow rate for fluids being produced from an oil and gas well, the fluids being pumped from the oil and gas well by a positive displacement pump;
• obtain a current pump speed for the positive displacement pump, the current pump speed corresponding to the current fluid flow rate for fluids being pumped from the oil and gas well by the positive displacement pump;
• calculate a theoretical fluid flow rate based on the current pump speed and one or more pump characteristics;
• calculate a pump fillage based on the theoretical fluid flow rate and the current fluid flow rate;
• compare the calculated pump fillage to a target pump fillage using a pump control algorithm and one or more tuning parameters;
• generate a corrected pump speed using the pump control algorithm and the one or more tuning parameters;
• and
• control a motor speed of the positive displacement pump using the corrected pump speed to optimize production of fluids from the oil and gas well while minimizing wear on the positive displacement pump.