【作者】 刘建敏；

【导师】 曲占庆；

【作者基本信息】 中国石油大学 ， 油气田开发工程， 2008， 硕士

【摘要】 近年来,抽油机井杆管偏磨井数在国内各油田均呈逐年增加的趋势,杆管偏磨已成为影响油井检泵作业的主要因素之一。影响杆管偏磨的主要因素有井眼弯曲、抽油杆柱失稳、含水率高、产出液具有腐蚀性、抽油杆柱振动等。不论是定向井还是直井,其井眼轨迹都是三维空间曲线,抽油杆柱在抽油井中的受力变形均具有三维特征。因此,准确地认识抽油杆三维受力状况对减少抽油杆事故、降低油气开采成本具有重要意义。研究井下抽油杆柱在三维井眼中的屈曲变形问题,能够为有效的解决杆管偏磨问题提供理论依据。通过理论分析建立了三维井眼中抽油杆柱受力模型,利用静力平衡法考虑杆柱所受浮力,推导了两端受压有重抽油杆柱在垂直井、斜直井、弯曲井眼中的屈曲微分方程和接触力方程。所得的屈曲微分方程和接触力方程均为四阶非线性常微分方程,利用解析方法对抽油杆柱在垂直井、斜直井和弯曲井眼中的屈曲微分方程进行了求解,得到了抽油杆柱在这三种情况下发生正弦屈曲和螺旋屈曲的临界载荷。并且得出了抽油杆柱在不同井眼中的变形规律及发生杆管偏磨的临界条件。明确了三维井眼中抽油杆柱的受力及变形形态后,提出了基于实际井眼轨迹的抽油杆柱设计方法及采用加重杆时的杆柱设计方法。实例计算表明,优化后的设计方法以抽油杆柱的实际受力及变形为基础,设计出的杆柱组合更合理。更多还原

【Abstract】 In recent years, the number of eccentric attrition oil well is large in domestic giant oilfield, and the eccentric attrition between the sucker rod and tubing becomes one of the factors which affect pump inspection operation. There are many reasons which affect eccentric attrition, for example, crooked drilling hole, buckling of the sucker rod, high water content, produced fluid with corrosiveness, rod string vibration and so on. No matter controlled directional well or straight well, the well courses are all 3D curves. The stress and deformation of the sucker rod string in oil well present 3D features, therefore accurate understanding of 3D force state is of great significance to reduce accidents and the cost of development. Studying the sucker rod string buckling in 3D wellbore can provide theoretical basis for effectively solving eccentric attrition. The sucker rod force model in 3D wellbore is established through theoretical analysis. The buckling differential equations and contact force equations of the sucker rod string suffered gravity, buoyancy and pressure at both ends in vertical well, slant hole, crooked hole are fetched by means of static balance. The equations fetched are all fourth-order nonlinear differential equations. The two critical loads of the differential equations of the sucker rod in different wellbore are computed using analytical method. The two critical loads are sinusoidal and helix buckling critical loads of sucker rod. The deformation laws of sucker rod in different wellbore and critical conditions of eccentric attrition are obtained. The sucker rod design method and designation adopting weight rod based on the 3D wellbore are proposed. The revised method is based on actual force and deformation, so it is more reasonable.更多还原