Erik Torseke, Tom Polk, & Steve Boren, ABB Inc.
The use of Variable Speed Drives to control Rod Pumps has been tried with varying results. The success has been limited due to issues such as surface equipment reliability, regeneration, voltage and current harmonics, poor power factor, and premature Rod, Tubing, and Pump failure. This paper describes a unique technology that combines the latest advances in power electronics with patented firmware and application software solutions resulting in optimized production and reduced maintenance and energy costs for heavy oil, high gas content and "problem" wells. The technology eliminates pump-off and allows the operator to maintain the fluid level at a predefined level above the pump, maximizing pump fillage, while accurately controlling the rod speed at all times preventing premature rod failure. This new technology also produces a near unity power factor and a minimum of voltage and current harmonics and allows the use of more cost efficient high efficiency NEMA B motors.