Controlled Pneumatic Well Pumping System, And Method For Optimizing Pump Stroke Speed

摘要

A closed loop pneumatic pumping system is provided. The system uses a gas compressor and a high pressure gas tank to exert pneumatic pressure against a reciprocating piston over a wellbore. The piston is connected to a rod string and downhole pump for pumping formation fluids from a wellbore. The system includes an electronic controller that controls movement, including pump speed of the piston as it cycles between upstrokes and downstrokes within a cylinder over the wellbore. In one aspect, speed is controlled by adjusting a speed of the compressor. In another aspect, speed is controlled by adjusting the position of an upstroke control valve and a downstroke control valve. In one aspect, the pump stroke controller is configured to adjust a speed of the upstroke and a speed of the downstroke in response to signals indicative of pump fillage. A method for optimizing pneumatic pumping speed at a wellbore is also provided herein.

主权项

1. A pneumatic pumping system for a wellbore, comprising:
an elongated cylinder defining a tubular body disposed vertically over the wellbore; an elongated polished rod residing substantially within the cylinder; a piston connected to the polished rod that is movable between upper and lower positions within the cylinder; a rod string that is mechanically connected to and that extends downwardly from the polished rod, the rod string being configured to extend into the wellbore; a positive displacement pump disposed at a lower end of the rod string, the pump being configured to pump formation fluids from the wellbore; a high pressure gas tank; a compressor configured to pump a working gas from one or more low pressure gas tanks into the high pressure gas tank, and then into the cylinder to create an upstroke of the piston and the operatively connected pump; the one or more low pressure gas tanks, wherein the one or more low pressure gas tanks are configured to receive the pumped working gas from the cylinder during a downstroke of the piston and the operatively connected pump, and to return the working gas to the high pressure gas tanks via the compressor, thereby forming a closed loop pumping system; a position sensor disposed along the cylinder to monitor a vertical position of the piston within the cylinder in real time; a pressure transducer configured to monitor pressure within the cylinder in real time; and a controller configured to receive signals from the position sensor and the pressure transducer, and from those signals adjust upstroke speed, downstroke speed, or both.