Long-stroke pumping unit
First Claim
Patent Images
1. A pumping unit, comprising:
- a prime mover for reciprocating a rod string;
a tower;
a counterweight assembly movable along the tower;
a crown mounted atop the tower;
a belt having a first end connected to the counterweight assembly and having a second end connectable to the rod string; and
a dynamic control system for controlling a speed of the prime mover and comprising;
a load cell for measuring force exerted on the rod string;
a sensor for detecting position of the rod string, wherein the sensor is operable to detect a position of the rod string by detecting a position of the counterweight assembly;
an accelerometer for measuring vibration of the rod string or of a production string;
a meter for measuring power consumed by the prime mover; and
a controller operable to;
determine position of and load on a downhole pump connected to the rod string and the production string;
determine acceptability of two or more parameters of the pumping unit;
select a prime objective based on a hierarchy of the parameters and the acceptability of the parameters;
determine an upstroke speed, a downstroke speed, and turnaround accelerations and decelerations for the prime objective; and
monitor for failure of the rod string or belt and control descent of the counterweight assembly in response to detection of the failure.
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Accused Products
Abstract
A long-stroke pumping unit for driving rod includes a tower and a counterweight assembly movable along the tower. A crown is mounted atop the tower, and a sprocket is supported by the crown and rotatable relative to the crown. A belt connects the counterweight assembly to the rod. The unit further includes a motor having a stator mounted to the crown and a rotor torsionally connected to the sprocket. A sensor is used to detect a position of the counterweight assembly. The pumping unit may include a dynamic control system for controlling a speed of a motor.
46 Citations
19 Claims
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1. A pumping unit, comprising:
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a prime mover for reciprocating a rod string; a tower; a counterweight assembly movable along the tower; a crown mounted atop the tower; a belt having a first end connected to the counterweight assembly and having a second end connectable to the rod string; and a dynamic control system for controlling a speed of the prime mover and comprising; a load cell for measuring force exerted on the rod string; a sensor for detecting position of the rod string, wherein the sensor is operable to detect a position of the rod string by detecting a position of the counterweight assembly; an accelerometer for measuring vibration of the rod string or of a production string; a meter for measuring power consumed by the prime mover; and a controller operable to; determine position of and load on a downhole pump connected to the rod string and the production string; determine acceptability of two or more parameters of the pumping unit; select a prime objective based on a hierarchy of the parameters and the acceptability of the parameters; determine an upstroke speed, a downstroke speed, and turnaround accelerations and decelerations for the prime objective; and monitor for failure of the rod string or belt and control descent of the counterweight assembly in response to detection of the failure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A pumping unit, comprising:
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a prime mover for reciprocating a rod string; a tower; a counterweight assembly movable along the tower; a crown mounted atop the tower; a belt having a first end connected to the counterweight assembly and having a second end connectable to the rod string; and a dynamic control system for controlling a speed of the prime mover and comprising; a load cell for measuring force exerted on the rod string; a sensor for detecting position of the rod string, wherein the sensor is operable to detect a position of the rod string by detecting a position of the counterweight assembly and wherein the sensor is a linear variable differential transformer (LVDT) comprising; a string connected to the counterweight assembly and wound onto a spool; a screw shaft engaged with a thread of the spool; an LVDT core mounted to the screw shaft; and an LVDT body at least partially receiving the LVDT core; an accelerometer for measuring vibration of the rod string or of a production string; a meter for measuring power consumed by the prime mover; and a controller operable to; determine position of and load on a downhole pump connected to the rod string and the production string; determine acceptability of two or more parameters of the pumping unit; select a prime objective based on a hierarchy of the parameters and the acceptability of the parameters; and determine an upstroke speed, a downstroke speed, and turnaround accelerations and decelerations for the prime objective. - View Dependent Claims (17, 18, 19)
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Specification