Study On Corrosion Wear Behaviour Of High Performance Thin-walled Rope Coening Teel Drill Coating

Wire line coring drill pipe is often used in scientific drilling because of its high drilling efficiency,low labor intensity and cost saving,but its complex load state and poor working environment will lead to the failure of drill pipe,which seriously affects the development of drilling engineering.In this paper,the corrosion law of 27 Cr Mo V substrate and WC-10Co4 Cr coating used in real drilling under simulated drilling fluid at different temperatures,flow rates,the friction and wear conditions under different loads are analyzed,and then the measured parameters obtained in the laboratory are used as the boundary conditions of simulation to simulate the electrochemical corrosion and flow erosion of drill pipe under real working conditions of multi physical field coupling simulation The test and simulation verify each other,and get a more reliable physical model,it provides reference for engineering application.The main research contents are as follows:(1)Corrosion resistance of 27 Cr Mo V steel drill pipe with or without WC-10Co4 Cr coating under simulated dynamic condition.This paper studies the corrosion behavior of 27 Cr Mo V drill pipe matrix with or without WC-10Co4 Cr coating at different temperatures of40?,80? and 120? and different flow rates of 0.25m/s and 0.45m/s under the simulated drilling fluid environment of 4MPa.The results show that as the temperature rises,the corrosion of the substrate becomes more serious,but the corrosion begins to slow down at 120?,and when the temperature increases,the protective effect of the coating becomes better.The corrosion resistance of substrate and coating will decrease with the increase of flow rate,but the self-corrosion potential of the coating is still far lower than that of the substrate at each flow rate.(2)Research on wear resistance of 27 Cr Mo V steel drill pipe with or without WC-10Co4 Cr coating.Study the law of wear resistance of 27 Cr Mo V substrate and WC-10Co4 Cr coating under 1000 g,1500g,2000 g load: it is found that with the increase of load,the wearability of top coat is better than that of the matrix.The wear types of 27 Cr Mo V matrix surface are adhesion and a small amount of oxidation,and the WC-10Co4 Cr top coat are grains and fatigue.the coating has not been damaged,and Fe3O4 and Cr oxides were formed after the friction experiment of the substrate and the coating,respectively.(3)Simulation study of downhole corrosion and erosion of drill pipe coupling multi-physics under simulated real working conditionsIn this paper,considering the existence of diffusion,electromigration,flow field,temperature,and stress field,The simulation of drill pipe corrosion shows that the severity of drill pipe corrosion increases with the increase of depth,and the effect of drilling fluid temperature on the corrosion is greater than the stress..At the same time,considering the impact of erosion on the drill pipe on the basis of electrochemical corrosion,it is concluded that the erosion mode of the inner wall of the drill pipe is mainly collision erosion,and the outer wall is the combined effect of collision erosion and cutting erosion.Near the connection between the rod and the drill rod.In the simulation study,the corrosion resistance and erosion degree of the coating are higher than that of the substrate.