Controller and method of controlling a rod pumping unit
AssigneeRavdos Holdings Inc.
InventorsOmar Al Assad, Rogier Sebastiaan Blom, Gary Hughes, Justin Edwin Barton, Peter Westerkamp
Life of this patent
Estimating the term…
Abstract
A controller for operating a rod pumping unit at a pump speed. The controller includes a processor configured to operate a pump piston of the rod pumping unit at a first speed. The processor is further configured to determine a pump fillage level for a pump stroke based on a position signal and a load signal. The processor is further configured to reduce the pump speed to a second speed based on the pump fillage level for the pump stroke.
Claims18
A controller for operating a rod pumping unit, said controller comprising a processor configured to:
- determine a pump fillage level for the pump stroke based on a position signal and a load signal;
- establish an average pump speed based on the pump fillage level;
- operate a pump piston of the rod pumping unit on a downstroke of a pump stroke;
- decelerate the pump piston on the downstroke as the pump piston approaches a fluid surface in a barrel of a pump of the rod pumping unit;
- detect if an overstress caused by the deceleration of the pump piston is present, wherein if the overstress caused by the deceleration of the pump piston is detected during the downstroke, the deceleration of the pump piston is reduced to mitigate the overstress;
- and
- increase the pump speed on the downstroke after the pump piston contacts the fluid surface in said barrel of said pump to achieve the established average pump speed.
A method of controlling a rod pumping unit, said method comprising determining a pump piston position and a pump piston load;
- computing a pump fillage level based on the pump piston position and the pump piston load;
- operating the rod pumping unit at a pump speed equal to a first speed on a downstroke of the rod pumping unit;
- reducing the predetermined pump speed on the downstroke to a second speed based on the pump fillage level and the pump piston position as the pump piston approaches a fluid surface in a barrel of the rod pumping unit,
- detecting if an overstress caused by the reduction in the predetermined pump speed is present, wherein if the overstress is detected during the downstroke, modulating the reduction of the predetermined pump speed on the downstroke to mitigate the overstress;
- and
- increasing the pump speed to a third speed on the downstroke after the pump piston contacts the fluid surface within the barrel of the rod pumping unit.
A rod pumping unit, comprising:
- a pump comprising a pump piston and a barrel, said pump piston operable within said barrel;
- a rod coupled to a motor and said pump, said rod configured to operate said pump at a pump speed;
- and
- a controller coupled to said motor and configured to:
- set a target average pump speed for the stroke based on the pump fillage level;
- drive said pump piston on a downstroke at the pump speed, the pump speed equal to a first speed;
- decelerate said pump piston on the downstroke to make the pump speed equal to a second speed as the pump piston approaches a fluid surface within said barrel,
- detect if an overstress is present while the pump piston is decelerated, wherein if the overstress is detected during the deceleration, the deceleration is reduced to mitigate the overstress;
- and
- accelerate said pump piston on the downstroke after said pump piston contacts the fluid surface within said barrel, wherein the pump piston is accelerated to a speed to achieve the target average pump speed for the pump stroke.
Dependencies are inferred from the claim text.