Electrical Motor Power Measurement as the Key for Optimized Rod Pumping

McCoy, J.N. (Echometer Co.) | Podio, A.L. (University of Texas at Austin) | Ott, Russ (Mobil Exploration and Production U.S.) | Woods, Mike (Mobil Exploration and Production U.S.)


The development of accurate digital measurement of instantaneous powerduring a pump stroke has made possible a very quick and detailed analysis ofthe efficiency of the pumping system. The efficiency is then used as thebenchmark for determining whether a complete well performance analysis iswarranted from the standpoint of making best use of personnel and economicresources to increase oil production.

In addition, power measurement provides direct information about liftingcost per barrel of fluid and barrel of oil produced, electrical and mechanicalloading of the prime mover, peak power demand, power factor and minimumrequired ratings. These results give operating personnel information regardingpotential problems and give to management a complete picture of thedistribution of pumping costs.

The power measurements are also converted, by the software, to instantaneoustorque and presented as continuous torque curves for the upstroke anddownstroke. This allows determination of the existing level of counterbalanceand provides the most rapid and accurate method for counterbalance adjustmentto achieve lower torque loading on the gear box and reduced energy utilization.One of the principal advantages of this balancing method is that counterbalanceadjustment can be made without need for an accurate description of the pumpingunit's geometry which is often unknown or inaccurate. The effect ofcounterweight displacement on torque and power is observed immediately byrepeating the power measurement after relocating the counterweights.

This paper presents a series of case studies showing the Application ofpower measurement to a variety of pumping systems and components, includingconventional, Mark II, Rotaflexunits and high efficiency motors.