Drill-pipe tool joints in extended reach wells often suffer a shear failure.In view of this,an ultra-high torque double-shoulder pipe joint was designed according to the deformation compatibility relation of the drill...Drill-pipe tool joints in extended reach wells often suffer a shear failure.In view of this,an ultra-high torque double-shoulder pipe joint was designed according to the deformation compatibility relation of the drill-pipe tool joint under torque.It is structurally characterized by long primary and secondary shoulders,small thread taper and largefillet radius of bottom tooth.First,a 3D numerical simulation model was established for this type of joint,named the XSJ joint here,based on the principle of virtual work,the Von Mises yield criterion and the nonlinear contact theory.Second,orthogonal optimization was performed on its key structural parameters by means of the orthogonal opti-mization method.The optimal combination of key structural parameters of the XSJ joint is taper 1:16,thread pitch 6.55 mm,guiding surface angle 29,bearing surface angle 28,and tooth height 3.755 mm.Finally,the bearing performance and fatigue performance of this tool joint and the API tool joint were calculated and compared using the Simulia Abaqus fe-safe software.Compared with the API tool joint,the XSJ joint is better,and its tensile strength,torsion strength,bending strength and compression strength increase by 10.65%,62.5%,2.75%and 52%,respectively.Its tension compression fatigue life,bending fatigue life,torsion fatigue life and composite fatigue life increase by 1.19 times,1.74 times,550 times and 28.79%,respectively.It is concluded that the designed XSJ joint is significantly improved in term of torsion capacity while its tension strength,bending strength and compression strength are not decreased,so it can better meet the drilling conditions of extended reach wells.展开更多
Joints between two different grades of aluminium alloys are need of the hour in many light weight military structures.In this investigation,an attempt has been made to join the heat treatable(AA 6061) and non-heat tre...Joints between two different grades of aluminium alloys are need of the hour in many light weight military structures.In this investigation,an attempt has been made to join the heat treatable(AA 6061) and non-heat treatable(AA 5086) aluminium alloys by friction stir welding(FSW)process using three different tool pin profiles like straight cylindrical,taper cylindrical and threaded cylindrical.The microstructures of various regions were observed and analyzed by means of optical and scanning electron microscope.The tensile properties and microhardness were evaluated for the welded joint.From this investigation it is founded that the use of threaded pin profile of tool contributes to better flow of materials between two alloys and the generation of defect free stir zone.It also resulted in higher hardness values of 83 HV in the stir zone and higher tensile strength of 169 MPa compared to other two profiles.The increase in hardness is attributed to the formation of fine grains and intermetallics in the stir zone,and in addition,the reduced size of weaker regions,such as TMAZ and HAZ regions,results in higher tensile properties.展开更多
Based on the three-dimensional elastic-plastic finite element analysis of the 8"(203.2 mm)drill collar joint,this paper studies the mechanical characteristics of the pin and box of NC56 drill collar joints under ...Based on the three-dimensional elastic-plastic finite element analysis of the 8"(203.2 mm)drill collar joint,this paper studies the mechanical characteristics of the pin and box of NC56 drill collar joints under complex load conditions,as well as the downhole secondary makeup features,and calculates the downhole equivalent impact torque with the relative offset at the shoulder of internal and external threads.On the basis of verifying the correctness of the calculation results by using measured results in Well GT1,the prediction model of the downhole equivalent impact torque is formed and applied in the first extra-deep well with a depth over 10000 m in China(Well SDTK1).The results indicate that under complex loads,the stress distribution in drill collar joints is uneven,with relatively higher von Mises stress at the shoulder and the threads close to the shoulder.For 203.2 mm drill collar joints pre-tightened according to the make-up torque recommended by American Petroleum Institute standards,when the downhole equivalent impact torque exceeds 65 kN·m,the preload balance of the joint is disrupted,leading to secondary make-up of the joint.As the downhole equivalent impact torque increases,the relative offset at the shoulder of internal and external threads increases.The calculation results reveal that there exists significant downhole impact torque in Well SDTK1 with complex loading environment.It is necessary to use double shoulder collar joints to improve the impact torque resistance of the joint or optimize the operating parameters to reduce the downhole impact torque,and effectively prevent drilling tool failure.展开更多
文摘Drill-pipe tool joints in extended reach wells often suffer a shear failure.In view of this,an ultra-high torque double-shoulder pipe joint was designed according to the deformation compatibility relation of the drill-pipe tool joint under torque.It is structurally characterized by long primary and secondary shoulders,small thread taper and largefillet radius of bottom tooth.First,a 3D numerical simulation model was established for this type of joint,named the XSJ joint here,based on the principle of virtual work,the Von Mises yield criterion and the nonlinear contact theory.Second,orthogonal optimization was performed on its key structural parameters by means of the orthogonal opti-mization method.The optimal combination of key structural parameters of the XSJ joint is taper 1:16,thread pitch 6.55 mm,guiding surface angle 29,bearing surface angle 28,and tooth height 3.755 mm.Finally,the bearing performance and fatigue performance of this tool joint and the API tool joint were calculated and compared using the Simulia Abaqus fe-safe software.Compared with the API tool joint,the XSJ joint is better,and its tensile strength,torsion strength,bending strength and compression strength increase by 10.65%,62.5%,2.75%and 52%,respectively.Its tension compression fatigue life,bending fatigue life,torsion fatigue life and composite fatigue life increase by 1.19 times,1.74 times,550 times and 28.79%,respectively.It is concluded that the designed XSJ joint is significantly improved in term of torsion capacity while its tension strength,bending strength and compression strength are not decreased,so it can better meet the drilling conditions of extended reach wells.
基金the support extended by the Centre for Materials Joining & Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar, India to carry out this research
文摘Joints between two different grades of aluminium alloys are need of the hour in many light weight military structures.In this investigation,an attempt has been made to join the heat treatable(AA 6061) and non-heat treatable(AA 5086) aluminium alloys by friction stir welding(FSW)process using three different tool pin profiles like straight cylindrical,taper cylindrical and threaded cylindrical.The microstructures of various regions were observed and analyzed by means of optical and scanning electron microscope.The tensile properties and microhardness were evaluated for the welded joint.From this investigation it is founded that the use of threaded pin profile of tool contributes to better flow of materials between two alloys and the generation of defect free stir zone.It also resulted in higher hardness values of 83 HV in the stir zone and higher tensile strength of 169 MPa compared to other two profiles.The increase in hardness is attributed to the formation of fine grains and intermetallics in the stir zone,and in addition,the reduced size of weaker regions,such as TMAZ and HAZ regions,results in higher tensile properties.
基金Supported by the National Natural Science Foundation of China(52174003,52374008).
文摘Based on the three-dimensional elastic-plastic finite element analysis of the 8"(203.2 mm)drill collar joint,this paper studies the mechanical characteristics of the pin and box of NC56 drill collar joints under complex load conditions,as well as the downhole secondary makeup features,and calculates the downhole equivalent impact torque with the relative offset at the shoulder of internal and external threads.On the basis of verifying the correctness of the calculation results by using measured results in Well GT1,the prediction model of the downhole equivalent impact torque is formed and applied in the first extra-deep well with a depth over 10000 m in China(Well SDTK1).The results indicate that under complex loads,the stress distribution in drill collar joints is uneven,with relatively higher von Mises stress at the shoulder and the threads close to the shoulder.For 203.2 mm drill collar joints pre-tightened according to the make-up torque recommended by American Petroleum Institute standards,when the downhole equivalent impact torque exceeds 65 kN·m,the preload balance of the joint is disrupted,leading to secondary make-up of the joint.As the downhole equivalent impact torque increases,the relative offset at the shoulder of internal and external threads increases.The calculation results reveal that there exists significant downhole impact torque in Well SDTK1 with complex loading environment.It is necessary to use double shoulder collar joints to improve the impact torque resistance of the joint or optimize the operating parameters to reduce the downhole impact torque,and effectively prevent drilling tool failure.
