Experimental device for evaluating pumping oil polish rod coating for fatigue strength influence

Abstract

The invention discloses a test device for evaluating the effect of an oil pumping polished rod coating upon a fatigue strength, including a three-point bending test machine, a tension-tension fatigue test machine and an analysis sample, the three-point bending test machine includes a pressure adding roller wheel, a pressure head clip, a three-point bending support and a support roller post, the tension-tension fatigue test machine includes an upper fixture, the pressure adding roller wheel and the pressure head clip of the three-point bending test machine which are arranged into integration in the upper fixture, wherein, the upper fixture connects with a control system through a sensor and connecting lines, the analysis sample is horizontally placed on the support roller post of the three-point bending test machine, and the pressure adding roller wheel faces a rod-like fatigue sample. Through combining the control system of the tension-tension fatigue test machine and the support and the pressure head of the three-point bending test machine, a three-point bending test can be carried out to realize the simulation of the bending fatigue process in the scope of 10 centimeters underneath the clip of the oil pumping polished rod in oil field site, when using the device of the invention, the effect of the coating upon the fatigue strength can be effectively evaluated.

Description

technical field [0001] The invention relates to an experimental device in the field of petroleum equipment, in particular to an experimental device for evaluating the influence of the coating of an oil pumping rod on the fatigue strength. Background technique [0002] Pumping wells have always been the main method of oil production in oilfields at home and abroad. With the increasing number of deep oil wells, heavy oil wells and high water cut wells, alloy coated polished rods have been widely used for their excellent corrosion resistance and wear resistance. However, due to the metallurgical bond between the polished rod substrate and the coating due to the preparation process of the alloy coating, the influence of the coating on the fatigue performance of the oil pumping polished rod is becoming more and more critical. More than 80% of the polished rods in the oil field are broken under the clips Bending fatigue fracture within 10 cm. [0003] At present, there is no spe...

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Problems solved by technology

[0004] But in fact, the fatigue performance investigated by this pull-pull fatigue test method is mostly determined by the tensile strength of the polished rod, and this method cannot reflect the real influence of the coating on the fatigue performance

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