System for monitoring oil well performance

Abstract

A system for monitoring performance of a pumping unit of an oil well includes a first sensor for measuring the inclination angle of a beam forming part of the pumping unit, a second sensor for measuring the load on the beam, and a third sensor for measuring the load on an electrical motor used in conjunction with the pumping unit. The first sensor includes a cantilevered pendulum member which moves in response to changes in the beam inclination angle and strain gauges affixed to the pendulum member for generating an electrical signal indicative of the instantaneous inclination angle. The second sensor includes a deformable sensor plate mounted to the beam and piezoresistive gauges attached to the plate for providing a signal indicative of the load on the beam. The third sensor includes a sensor head attached to a cable for supplying electrical power to the motor. The sensor head includes a sensor coil spaced from the cable so that the magnetic field surrounding the cable induces a current flow in the sensor coil. By measuring the voltage across the ends of the sensor coil, a signal indicative of the load on the motor is generated.

Dependencies are inferred from the claim text.