一种深海复合采油立管的设计与性能研究

发布时间：2019-06-12 18:45

【摘要】：立管是海上油气开发的重要设备之一。较浅海比,深海立管所处的海洋环境更为恶劣。所以,深海采油立管在设计时,对材料选择、结构形式以及制造安装工艺的要求非常高,一般单层立管很难达到此标准。目前,复合立管由于其结构形式丰富,力学性能良好,在深海采油领域应用日益广泛。由于立管在海下作业时受到的力较为复杂,设计时需要考虑立管在各种载荷作用下的响应情况。本文的研究内容如下:(1)设计了一种具有高抗拉性能的深海采油立管。该立管采用高抗拉强度的钢带作为外层材料包裹在强度级别相对较低的可焊管外壁制成,立管包括内管、轴向钢带层及2层不同角度铺设的螺旋钢带层共4层。该设计采用卡槽式机械连接的方式对两种不可焊高强度钢进行复合,使得立管的结构形式更为丰富。不仅强度高、重量轻而且没有焊缝,大大提高了立管在接头处的强度。(2)提出了复合立管在弯曲载荷下结构响应的分析模型,推导了在极坐标系下钢带层应变与螺旋铺设角度、方位角度坐标之间的关系,通过应变能同外力矩做功相等的原理,得出了复合立管螺旋钢带层弯曲刚度的计算公式,从机理上揭示复合立管的弯曲响应特性。(3)分析了该复合立管在轴对称载荷作用下的响应。首先,给出了轴对称载荷作用下复合立管各层响应的未知变量;然后,根据平衡方程、本构方程和变形协调方程,推导出了与未知变量相对应的方程组;最后,得到复合管在轴对称载荷作用下的响应方程,并探讨了螺旋钢带层的铺设角度与复合立管整体响应的关系。(4)对复合立管模型进行数值模拟,分别分析了复合立管在弯曲载荷、轴向拉力和轴向扭矩作用下的结构响应。先使用ANSYS的APDL语言编写脚本程序对立管的螺旋钢带层进行参数化建模,再将模型导入ABAQUS有限元软件中与内管、轴向钢带层组装成共4层复合立管有限元模型,通过计算得到复合立管的螺旋钢带层的轴向应力沿复合立管纵向的变化关系,得到复合立管整体响应情况,并将刚度计算结果与理论计算结果进行了对比。
[Abstract]:Riser is one of the important equipment for offshore oil and gas development. The marine environment of the deep sea riser is worse than that of the shallow sea. Therefore, in the design of deep-sea oil recovery riser, the requirements for material selection, structure form and manufacturing and installation technology are very high, and it is difficult for single-layer riser to meet this standard. At present, the composite riser is widely used in the field of deep-sea oil recovery because of its rich structure and good mechanical properties. Because the force of riser under sea is more complex, the response of riser under various loads should be considered in the design. The research contents of this paper are as follows: (1) A deep-sea oil recovery riser with high tensile performance is designed. The riser is made of steel strip with high tensile strength as outer material wrapped in the outer wall of weldable pipe with relatively low strength level. the riser consists of four layers of inner pipe, axial steel strip layer and two spiral steel strip layers laid at different angles. In this design, two kinds of non-weldable high strength steel are combined by slot mechanical connection, which makes the structure of riser more abundant. Not only the strength is high, the weight is light, but there is no weld, which greatly improves the strength of riser at the joint. (2) the analysis model of structural response of composite riser under bending load is put forward, and the relationship between the strain of steel strip layer and the coordinates of spiral laying angle and azimuth angle in polar coordinate system is derived. through the principle that the strain energy is equal to the external force moment, the calculation formula of bending stiffness of spiral steel strip layer of composite riser is obtained. The bending response characteristics of the composite riser are revealed from the mechanism. (3) the response of the composite riser under axisymmetric load is analyzed. Firstly, the unknown variables of the response of each layer of the composite riser under axisymmetric load are given, and then, according to the equilibrium equation, the constitutive equation and the deformation coordination equation, the equations corresponding to the unknown variables are derived. Finally, the response equation of the composite pipe under axisymmetric load is obtained, and the relationship between the laying angle of the spiral steel strip layer and the overall response of the composite riser is discussed. (4) the numerical simulation of the composite riser model is carried out, and the structural response of the composite riser under bending load, axial tension and axial torque is analyzed respectively. Firstly, the script program of ANSYS is used to program the parametric modeling of the spiral steel strip layer of the pipe, and then the model is introduced into the ABAQUS finite element software to assemble a total of four layers of composite riser finite element model. The axial stress of the spiral steel strip layer of the composite riser changes along the longitudinal direction of the composite riser, and the overall response of the composite riser is obtained. The stiffness calculation results are compared with the theoretical calculation results.
【学位授予单位】：江苏科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE952

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