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SPE 37499
Motor Power/Current Measurement for Improving Rod Pump Efficiencies
This paper was prepared for presentation at the 1997 SPE Production Operations Symposium, held in Oklahoma City, OK 9 – 11 March 1997.
The development of accurate digital measurement of instantaneous power during a pump stroke has made possible a very quick and detailed analysis of the efficiency of the pumping system. The efficiency is then used as the benchmark for determining whether a complete well performance analysis is warranted from the standpoint of making best use of personnel and economic resources to increase oil production.
In addition, power measurement provides direct information about lifting cost per barrel of fluid and barrel of oil produced, electrical and mechanical loading of the prime mover, peak power demand, power factor and minimum required ratings. These results give operating personnel information regarding potential problems and give to management a complete picture of the distribution of pumping costs.
The power measurements are also converted, by the software, to instantaneous torque and presented as continuous torque curves for the upstroke and downstroke. This allows determination of the existing level of counterbalance and provides the most rapid and accurate method for counterbalance adjustment to achieve lower torque loading on the gear box and reduced energy utilization. One of the principal advantages of this balancing method is that counterbalance adjustment can be made without need for an accurate description of the pumping unit’s geometry which is often unknown or inaccurate. The effect of counterweight displacement on torque and power is observed immediately by repeating the power measurement after relocating the counterweights.
This paper presents a series of case studies showing the application of power measurement to a variety of pumping systems and components, including conventional, Mark II, Rotaflex units and high efficiency motors.
Copyright 1997, Society of Petroleum Engineers, Inc.
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