The Structure Design And Finite Element Analysis For Micro-marking Teeth Of Hydraulic Tubing Tong

With the development of oil and gas production,the environment of downhole becomes complex,there exist a large amount of corrosive gas,especially hydrogen sulfide,which cause serious corrosion damage to underground pipe string.In order to reduce the impact of corrosion,oil field has been replaced the ordinary casing by CRA(corrosion resistant alloy casing).Conventional tongs was widely used on casing for on/off operation.The tong teeth destroyed the galvanized layer of CRA at the two ends of the casing surface,where the corrosion easily happened.A cone structure of teeth was designed to improve the conventional wedge clamp structure of teeth.The main research contents of this paper are as follows:(1)By consulting the Chinese and foreign references,ealized that the development status the micro teeth marks and the non teeth marks in recent years,as well as technical features and field applications.Summarized the factors of influencing casing corrosion,analysis of casing corrosion model,aware of the causes and characteristics of hydrogen sulfide corrosion.(2)According to the structure and working principle of hydraulic tong,based on the friction fatigue theory,the causes of wear and wearing process of the casing are explained,the model was built on the teeth contact area.The contact stress and strain function of the casing are obtained.To determine the main factors that affect the depth of teeth marks.Analysis of the elastic-plastic deformation in the on/ff process of the casing pipe.(3)The mechanics model was established for the conventional wedge teeth and cone teeth.According to the theory of elastic plastic mechanics,analysed contact stress between teeth and casing,calculated the stress function,concluded the stress component.During the different stages of on/off operation.Analysis of the tong teeth in the process of gradually tightening the casing,obtained elastic-plastic deformation of casing material surface.(4)In order to get finite element simulation of the teeth,using Pro/E software to build the model of teeth.With the help of ANSYS finite element software,According to the main factors affecting the depth of teeth marks,after the simulation results,comprehensive analysis and comparison,the optimal teeth was recommended.