Chemistry and Technology of Fuels and Oils, Vol.51, No.4, 371-378, 2015
Two Techniques for Reducing Sucker-Rod Loads in Deep Wells
Deep and superdeep reservoirs over 5000 m deep are continually being discovered and developed in Western China, particularly in the Tarim Basin. The low pressure in these reservoirs makes it necessary to run sucker-rod pumps to great depths, which increases the load on the polished rod and creates pumping problems in deep wells. This study examines two rod-load-reduction techniques for deep wells, one using composite fiberglass-steel rods and the other using load reducers for the rods. The effects of these techniques on polished-rod load reduction are evaluated by calculation based on well operation data and comparison of the two techniques. Energy efficiency is analyzed by calculating the torque based on the difference between the maximum and minimum loads on the polished rod. The study results show that composite fiberglass-steel rods reduce the maximum load by 35.7% and that the load reducer decreases the load by an average of 22.8%, which is a significant outcome. The composite fiberglass-steel rod is more energy efficient than the load reducer.
Keywords:deep wells;fiberglass-steel composite rods;load reducers;polished rod;load-reducing effects