Oil Well Monitoring System Using Current Signature Analysis

Abstract

The Pump Jack systems at oil wells are used to extract oil from the well. The changes in well characteristics and equipment wear affect the production of the oil. The un- necessary pump off condition due to breakdown will affect on the efficiency of the pump, reduce the production and increases the cost of production. So to avoid the unnecessary pump off conditions, continuous monitoring system is necessary. Also to increase the production, the pump is kept on to run continuously at optimal speed. In the ideal situation, the electrical system monitors the oil extraction and then matches the pump's speed via a sensors mounted on the well rod. Today's pump-off controller monitors the amount of oil being extracted, and then uses those measurements to match the speed of the motor/pump to the reservoir. With the industrial growth, it has become necessary to monitor the condition of the machine/system In the cur- rent signature analysis the motor is used as a transducer, no external transducer is required. The load on the rod is analysed using the motor current. The displacement capacity of a pumping system is designed to meet or exceed the fluid in flow from the reservoir. The load on the well rod is not constant but varies with the time. The load on the rod string and beam position is continuously measured and this relationship is plotted to produce the "dynagraph" for each stroke of the pump. Various techniques are used to control the speed of three phase induction motor such as Direct Torque Control, Vector Control and Closed Loop Feedback Control etc. In this study, the main emphasis will be given at first stage on the simulation and testing of the Vector Control Three Phase Induction Motor Drive. At the second stage, the software is designed for monitoring of SRP Wells. Then LCD display is interfaced with the drives for plotting the "dynagraph" which is used for signature analysis.