深海悬链线管中管的载荷传递特性及接触作用机理研究

Coiled tubing has an important role in deep-sea oil and gas projects, but it is prone to occur buckling phenomenon in operating process because of its small stiffness. Especially with the development of deep-sea oil and gas, the buckling of coiled tubing into the deep sea steel catenary riser is more prominent, and it even leades to job accidents. So it becomes a major bottleneck restricting on the technology promotion and application. The typical pipe in pipe problem has great significance, and it belongs to the frontier in the international. This project as follows: (1) The project uses non-linear statics analysis to explore the evolution mechanism of the coiled tubing's critical load, stress and strain under the catenary floating boundary, reveals slender flexible rod load transfer law; (2) Through introduction of the equivalent load about the waves, currents and other interference, it proposes contact interaction algorithm with the finite element method, explores the contact mechanism of the slender pipe-in-pipe in floating boundary;(3) It carry out the experimental study, optimizes the buckling and contact model of the slender tube with optimization theory in floating boundary. It expects to establish theoretical basis of the coiled tubing's application in the deep-sea steel catenary riser through this project, and it will supplement and perfect the theory of existing pipe string mechanics.

连续油管在深海油气工程中具有重要作用，但是因为其刚度小，在下入或作业 时难以承受轴向载荷易发生屈曲现象。特别是随着深海油气的开发，连续油管下入深海钢悬 链线立管的屈曲问题就越发凸显，甚至引发作业事故，成为制约该项技术推广应用的主要瓶 颈。这种典型管中管问题的研究具有重要意义，在国际上属于前沿领域。本项目的研究内容 为：(1)以悬链线浮动边界下的连续油管为研究对象，采用非线性静力学分析法探究临界载 荷、应力和应变的演变机制，揭示细长柔性杆在悬链线边界下的载荷传递规律；(2)引入波 浪、海流等干扰的分级等效载荷，采用有限元法提出接触作用算法，探究细长管中管在浮动 边界下的接触作用机理；(3)开展实验研究，运用最优化理论优化悬链线浮动边界下的细长 柔性杆屈曲接触力学模型。通过本项目的研究，有望为连续油管在深海钢悬链线立管中的应 用奠定理论基础，补充和完善现有管柱力学理论。

连续油管由于其独有的优势已广泛应用于海洋油气作业的各个方面。本项目采用微元法构建了连续油管在海洋井筒的细长柔性杆力学模型，分析了海洋定向井和水平井中连续油管尺寸、摩擦系数、井斜角等参数对连续油管轴向载荷传递特性的影响；引入海流力、海浪力、立管接触力等参数，建立了连续油管在海洋立管中的力学模型，采用准静态算法分析了海洋立管与连续油管之间的互相作用，分析了连续油管尺寸、平台横移量、阻力系数、风力速度、海流速度、摩擦系数等参数对连续油管与悬链线立管的影响；根据连续油管海洋作业的具体工况，搭建了室内管中管测试系统，对连续油管处于海洋井筒及立管的理论力学模型进行了验证；通过实验的方法，分析了海洋立管受横向扰动对连续油管轴向受力的影响；以建立的力学模型为基础，编制了浮动边界连续油管力学分析软件1套。项目研究成果发表学术论文12篇，其中SCI收录3篇，EI收录3篇；研制3套实验装置；申请国家专利6项。通过本项目的研究，以上成果不仅在学术上有助于揭示连续油管在海洋立管中的轴向载荷传递特性，探究浮动边界下连续油管与立管的接触作用机理，丰富管柱力学理论，而且将会为连续油管海洋应用提供一定的理论指导。