Paper: Improved Method of Sucker Rod String Design

Beam pumping units have been the principal means of artificial lift in the oil field for many years. In recent times, stimulation in secondary recovery projects and encroaching water in water-drive reservoirs have made it necessary to lift more fluid than ever before. There have been several improvements in beam pumping equipment, causing it to remain the best method of artificial lift in most of our wells. A few of these improvements are unique pumping unit geometry, high-slip motors, rolled sucker-rod threads, and sprayed metal couplings. In several heavily loaded wells, Union Oil Company noted a large percentage of rod failures occurring in the lower section of the tapered rod strings. This triggered an evaluation of the current methods of tapered rod string design to see if improvements could be made in this area.