US 5,281,100 A · Well pump control system

Abstract

A well pumping system includes a pivotally mounted walking beam and "horsehead" connected to a downhole pump by a pump rod in the conventional manner. A hydraulic lift piston and cylinder and a pneumatic balance piston and cylinder are connected to the walking beam. A process control computer controls input signals to a hydraulic control valve for controlling the hydraulic cylinder rate and direction of travel to provide corresponding control over the motion of the walking beam. The computer receives input information from a position sensor indicating the displacement of the beam in its range of travel. The computer program also is responsive to a timer for determining actual stroke rate and acceleration of the beam. The computer monitors and controls operation of the hydraulics and pneumatics as the pumping unit produces the lift necessary to extract fluid from the well. The computer controls acceleration and deceleration of the walking beam assembly in accordance with a desired acceleration-versus-time and deceleration-versus-time waveform. Closed loop control is used to cause actual beam displacement, displacement rate and acceleration to follow a desired displacement, rate, and acceleration profile. As a result, any sudden movement or directional change is eliminated, and the system reduces energy consumption and wear and tear on the pumping equipment.

Claims23

Dependent claims

A well pumping system comprising:

a pivotally supported beam connected to a pump rod extending to a downhole pump in which the pump rod reciprocates when the beam pivots cyclically;
a drive piston and cylinder connected to the beam for displacing the beam cyclically over a stoke length in response to reciprocating motion of the drive piston;
piston drive means responsive to an input control signal for reciprocating the drive piston to control corresponding cyclical motion of the beam over the beam stroke length;
and
closed loop control means for producing the input control signal to the piston drive means as a function of time through out each cycle of beam displacement to control beam motion during the cycle, the closed loop control means including (a) means for sensing the actual positive of the beam throughout each cycle of beam displacement and producing a position signal representing the displacement of the beam during each cycle of beam motion;
(b) means responsive to the position signal for producing a velocity signal representing the actual velocity of the beam during each cycle of beam motion;
(c) means for producing a velocity control signal representative of a predetermined desired velocity-versus-time waveform representing desired velocity of the beam during each cycle of beam motion;
and (d) means for adjusting the input control signal to the piston drive means in accordance with a measured deviation between the velocity signal and the velocity control signal throughout the cycle of beam motion for causing the beam displacement to follow the desired velocity-versus-time waveform throughout each cycle of beam motion.

5 more elements

A well pumping system comprising:

a pivotally supported beam connected to a pump rod extending to a downhole pump in which the pump rod reciprocates when the beam pivots cyclically;
a drive piston and cylinder connected to the beam for displacing the beam cyclically over a stroke length in response to reciprocating motion of the drive piston;
piston drive means responsive to an input control signal for reciprocating the drive piston to control corresponding cyclical motion of the beam over an adjustable beam stroke length at an adjustable beam stroke rate;
closed loop control means for producing the input control signal to the piston drive means as a function of time throughout each cycle of beam displacement to control beam motion during the cycle, the closed loop control means including (a) means for sensing the actual position of the beam throughout each cycle of beam displacement and producing a position signal representing the displacement of the beam during each cycle of beam motion;
(b) means responsive to the position signal for producing a velocity signal representing the actual velocity of the beam during each cycle of beam motion;
(c) means for producing a velocity control signal representative of a predetermined desired velocity-versus-time waveform representing desired velocity of the beam during each cycle of beam motion;
and (d) means for adjusting the input control signal to the piston drive in accordance with a measured deviation between the velocity signal and the velocity control signal throughout the cycle of beam motion for causing the beam displacement to follow the desired velocity-versus-time waveform throughout each cycle of beam motion,
means for producing a first input signal representing an adjustable beam stroke length;
and
means for producing a second input signal representing an adjustable beam stroke rate;
in which the closed loop control means are responsive to the first and second input signals for adjusting the predetermined desired velocity-versus-time waveform.

8 more elements

Dependencies are inferred from the claim text.

Well pump control system

Life of this patent

Well pump control system

Life of this patent

Abstract

Claims23