2010-02 SUCKER ROD COUPLNG FRICTION IN HDPE LINED TUBING
Sucker rod coupling friction values are used by rod design software to calculate rod loads for bare steel tubing on steel couplings. The friction values for sucker rod couplings on HDPE lined tubing is not known or defined. Therefore, rod load calculations in HDPE lined tubing are problematic. Tests were performed to compare the coupling friction in HDPE lined tubing compared to bare steel tubing at various temperatures and side loads. The objective was to find the drag ration of rod couplings on HDPE lined tubing to that of bare steel tubing at various termperatures. The data was used to develop an equation to calculate the drag in HDPE lined tubing to that of bare steel tubing as a function of temperature. Although not quantitatvely analyzed in this study, a significant side load capacity difference between HDPE lined and bare tubing was also observed.