Partial Analysis And Numerical Simulation Of Non-bonded Flexible Pipe

Offshore oil and gas resources development system is composed of offshore platforms, subsea production systems and a variety of pipelines and cables, which can extract, collect and transport oil. Among the system, pipeline is the main transport mode of the entire oil and gas resource development process. The non-bonded flexible pipes has become one of the key transport equipment of the offshore oil and gas resources development process, relying on its special internal structure and good mechanical properties.The structure of non-bonded flexible pipe is primarily composed of multilayer material with different functions such as skeletal layer, compressive armor layer, tensile armor layer, the inner and outer jacket and the anti-friction layer. Its internal multi-layer structure is spirally wound together, there is a lot of contact and friction between the layers, resulting in a serious nonlinear characteristic of non-bonded flexible pipe, and making our presence in modeling and analysis become difficult to execute. In recent years, a large number of scholars have done researches and analysis of the non-bonded flexible pipe, on the basis of putting forward specific assumptions, conducting on a variety of predigestion, but the data and conclusions tend to have larger deviations with practical engineering. In addition, foreign technology in this area is strictly confidential and domestic research also start late, resulting in the used pipelines of domestic offshore oil and gas production are forced to purchase from abroad at high prices, which seriously affected the process of China’s energy strategy and economic development. Therefore, partial mechanical performance analysis and simulation of the non-bonded flexible pipes is the necessary process to lay foundation and provide basis for the flexible pipe’s early realization of China’s independent and mass production.This paper introduces the main structure and characteristics of the non-bonded flexible pipe, and carries out detailed study and summarize on research status, sorting out the theoretical formula model of flexible pipes used in the calculation, and the theory of finite element analysis method is introduced. On this basis, referring to the international authoritative laboratory sample tube parameters, simplifying each structural layer with simplified equivalent method, and selecting the appropriate unit type by comparing, three-dimensional finite element model is established by using finite element software ANSYS and the model is calculated under a variety of working conditions. Finally, comparing internationally recognized experimental data, which has been doing tests by foreign institutions, with the finite element simulation results and the theoretical formula calculation results, to verify the correctness of the modeling, drawing some relevant conclusions, provide a reference for engineering applications.