复杂结构井钻杆接头三维力学特性及结构改进研究

【作者】 张智；

【导师】 祝效华；

【作者基本信息】 西南石油大学 ， 机械工程， 2016， 硕士

【摘要】 随着超深井、水平井、定向井、大位移井以及大斜度井钻井技术在石油钻井工程中的广泛应用,由井下复杂工况引起的钻杆接头过早失效问题日益突出,导致钻井周期增长,成本增加,成为制约钻井工程效益的主要内素之一。目前国内使用的钻杆接头大部分是直接从国外引进或引进国外结构、国内生产,需支付大量进口费或专利费,导致国内钻杆接头加工企业投资高、风险大、利润低。近年来,国内外不少学者对钻杆接头进行了大量研究,多数采用二维轴对称模型,少数采用三维力学模型,但并未同时考虑螺纹升角和井眼弯曲作用等因素的影响,针对复杂结构井钻杆接头力学特性及超高抗扭双台肩钻杆接头研究鲜见报道。针对上述问题,基于虚功原理、Von Mises屈服准则及接触非线性理论,考虑螺纹升角和井眼弯曲作用的影响,建立钻杆接头的三维数值仿真模型与井眼曲率到加载弯矩的转换模型,研究钻杆接头的上扣特性,分析内外压差、井眼温度、摩阻扭矩、均匀磨损及井眼曲率对钻杆接头安全性的影响,考虑预紧力、弯曲载荷及动载安全系数,计算钻杆接头的极限承载能力。计算钻杆接头的最大应力集中系数,分析摩擦系数对应力集中系数的影响。基于材料S-N曲线,确定钻杆接头的弯曲疲劳S-N曲线理论模型,建立精确的疲劳有限元计算模型。运用多轴疲劳算法,计算钻杆接头在复合交变载荷下的疲劳寿命,分析残余应力与表而质量对疲劳寿命的影响。基于钻杆接头受扭时的变形协调关系,利用正交优化方法,设计一种超高抗扭双台肩钻杆接头。对比计算超高抗扭双台肩钻杆接头、普通双台肩钻杆接头及API钻杆接头的承载性能和疲劳性能,分析超高抗扭双台肩钻杆接头的上扣特性及其在弯曲井段的力学特性。研究结果表明:上扣扭矩给钻杆接头提供一定的初始接触压力,保证钻井作业时的连接强度与密封性能,上扣扭矩控制不当会降低钻杆接头的安全性。摩肌扭矩、均匀磨损及井眼曲率对钻杆接头的连接性能影响较大,考虑服役时的随机振动与冲击,复杂结构井钻杆接头的设计和选型应着重考虑摩阻扭矩、磨损及井眼曲率的影响。针对设计的每种钻杆接头,都应考虑常见的井眼曲率和轴向拉伸载荷进行极限工作拉力与极限工作扭矩的精细化数值计算,以确保其安全工作。在钻杆接头螺纹表而引入残余压应力和改善表而质量,可以大幅提高其疲劳寿命。超高抗扭双台肩钻杆接头各参数优组合为:锥度1:16、螺距6.55mm、导向而角度29°、承载而角度28°、牙高3.755mm。与API钻杆接头和普通双台肩钻杆接头相比,超高抗扭双台肩钻杆接头的抗拉性能提高10.65%和9.26%,抗扭性能提高62.50%和21.35%,抗弯性能提高2.75%和1.38%,抗压性能提高52.00%和5.56%。超高抗扭双台肩钻杆接头比API钻杆接头和普通双台肩钻杆接头的拉压疲劳寿命提高1.19倍和0.92倍,弯曲疲劳寿命提高1.74倍和1.22倍,扭转疲劳寿命提高550倍和57倍,复合疲劳寿命提高28.79%和15.45%。更多还原

【Abstract】 With the wide application of ultra deep well,horizontal well,directional well,large displacement well and highly deviated well drilling technologies in petroleum drilling engineering,the premature failure problem of drill pipe joint caused by underground complex working conditions is increasingly prominent,resulting in the increase of drilling period and drilling cost.Such problem has become one of the main factors to restrict drilling efficiency.Currently,many drill pipe joints serving in China,are foreign product or foreign technology structure.It needs a lot of fee and royalty payment,causing the processing enterprises of drill pipe joint to high investment,high risk and low profit.In recent years,many domestic and foreign scholar have conducted a lot of research on drill pipe joint,but are mainly focused.on the 2D axisymmetric model,a few use of 3D mechanical model and it does not consider the influence of the angle of thread and the bending of the hole at the same time.Rare research has been reported on mechanical property of drill pipe joint in complex structural well and the super high anti twist double shoulder drill pipe joint.In view of the above problems,a 3D numerical simulation model of drill pipe joint and the converted model of borehole curvature to loading moment have been established based on the principle of virtual work,Von Mises yield criterion and nonlinear contact theory.It considers the influences of the angle of the thread and the bending of the hole.So as to study the make-up property and the influences of internal and external pressure difference,wellbore temperature,friction torque,uniform wear and borehole curvature on safety of drill pipe joint.To calculate the ultimate bearing capacity of drill pipe joint by considering preload,bending load and dynamic load safety factor.The max stress concentration factor of drill pipe joint is calculated,and the effect of friction coefficient on the stress concentration factor is analyzed.Based on the material S-N curve,the theoretical model of the bending fatigue S-N curve of drill pipe joint is determined,and the accurate fatigue finite element calculation model is established.To calculate fatigue life of drill pipe joint under composite alternating load by using the multi axis fatigue algorithm,and analyze the influences of residual stress and surface quality on fatigue life.Based on the deformation coordination relationship of drill pipe joint,a kind of excellent performance of the super high anti twist double shoulder drill pipe joint is designed by using the orthogonal optimization method.Compared with the bearing performance and fatigue performance of the super high anti twist double shoulder drill pipe joint,ordinary double shoulder drill pipe joint and API drill pipe joint.So as to analyze the make-up property of the super high anti twist double shoulder drill pipe joint and its 3D mechanical property in the curved section.Research results have shown that the make-up torque can provide a certain initial contact pressure for drill pipe joint to ensure its connection strength and sealing performance in drilling operation.The make-up torque improper control can reduce the safety of drill pipe joint.The friction torque,uniform wear and borehole curvature have great influences on the connection performance of drill pipe joint.In consideration of random vibration and shock of service,the drill pipe joint used for complex well should be designed and selected based on the influences of friction torque,wear and borehole curvature.For each kind of drill pipe joint to be designed,the accurate numerical calculation of the ultimate working pull and the ultimate working torque should be conducted on the corresponding borehole curvature and axial tensile load to ensure work safety.The introduction of residual compressive stress and improving the surface quality can significantly improve the fatigue life of drill pipe joint.The optimal combination of parameters of the super high anti twist double shoulder drill pipe joint is taper 1:16,pitch 6.55mm,guiding plane angle 29°,bearing surface angle 28°,tooth height 3.755mm.Compared with API drill pipe joint and ordinary double shoulder drill pipe joint,the super high anti twist double shoulder drill pipe joint tensile strength increase 10.65%and 9.26%,torsion strength increase 62.50%and 21.35%,bending strength increase 2.75%and 1.38%,compression strength increase 52.00%and 5.56%.The super high anti twist double shoulder drill pipe joint tension compression fatigue life increase 1.19 times and 0.92 times,bending fatigue life increase 1.74 times and 1.22 times,torsion fatigue life increase 550 times and 57 times,composite fatigue life increase 28.79%and 15.45%.更多还原