Research On Effects Of Na~+ On Wear Properties Of NBR/FKM

Recently,the application of electrical submersible-motor-driven progressive cavity pumping technology(ESPCP)expands rapidly in the major oilfield.The core components of the cavity pump consist of rubber stator and metal rotor,in which the stator rubber is particularly important.Although,the wear of stator rubber directly affect the efficiency and service life of cavity pump,but the failure mode、causes of stator rubber material and influencing factor are barely researched by the scientists in China or abroad,which restricts the development of the stator rubber used in cavity pump.From a single point of view,this paper mainly research on effects of Na+,the chemical composition which can be found commonly in crude oil,on the stator rubber of screw pump,and analyze the influencing factors,influencing factors and mechanism of action.In order to better describe the effects of Na+on NBR/FKM better,simulation experiment is carried out in the laboratory,the test is divided into four groups:wear tests under water friction,wear tests under NaCl solution friction,wear tests under Na2SO4 solution friction and swelling tests in water、NaCl and Na2SO4 solution.MVP-600 block ring testing machine was used to test NBR and FKM,which is commonly used as screw pump stator rubber.After the experiment,stereological microscopy specimen was used to observe the surface and the FI-IR was used to analyze element diffusion of the rubber’s surface,which provide theoretical basis of wear mechanism for rubber.Through the analysis and discussion of the experimental results,the conclusion briefly summarized of this paper drew as follows:1)wear performance of two kinds of rubber can be decreased by NaCl solution,wear volume is increased and service life is reduce,at the same time,wear performance of FKM is better than that of NBR in water or NaCl solution;2)Na+is the main component effects wear properties of NBR and FKM in NaCl solution;3)with the increase of the concentration of Na+,wear properties of NBR and FKM decreases;4)abrasion loss of rubber could be aggravated after swelling.