ADJUSTABLE SPEED DRIVES (ASD'S) FOR ARTIFICIAL LIFT SYSTEMS
For years we have known that "Long and Slow" is considered a Best Practice for rod pumped wells and that continuous running is best for ESP"s. In a perfect world we would have the ability to slow down or speed up a pump unit or ESP to match fluid inflow and to vary the speed of the up and down stroke of the rod pump system to minimize rod buckling. In reality, we design a rod pump system for 80 to 85% run time and minimize pump off pounding with a POC. Our ability to do this is often limited by pump unit or sheave size. Fluctuating production results in high fluids or cycling of the artificial lift system. For ESP's we usually adjust the operating frequency based on monthly fluid shots. The industry recently took a step toward that "Perfect World" with Adjustable Speed Drives (ASD"s).