Research On The Design Of Underwater Buoyancy Equipment Of Marine Flexible Riser

Marine flexible riser is an important equipment in the development of ocean oil and gas resources. The flexible riser has better compliance and can be applied in a more hostile environment compared with the rigid riser. A certain configuration for flexible riser need to be designed to improve the performance of the riser against from the damage caused by environmental loads during the service process. There are several equipment to maintain the design configuration of flexible riser such as buoyancy equipment, bending protection equipment, connecting equipment, etc. Distributed buoyancy module is selected as the most useful buoyancy equipment. At present, distributed buoyancy module products that are used interiorly rely heavily on imports. However, products made by foreign companies have been well developed, and they have intellectual property. So the research on distributed buoyancy modules will help our country to improve localization of products breaking the foreign monopoly, which would promote the development of marine industry.In this paper the research focuses on the basic design and application design of distributed buoyancy module products, trying to provide the overall design of buoyancy modules with exacuation process. First of all the development and research status of distributed buoyancy module product are inveatigated and summarized and it is importance to study the keyissues, of distributed buoyancy module. Then, considering the design factors of distributed buoyancy module, load cases, failure modes, design criteria based on research result are presented systematically. The basic design parameter, design content and design method of different part in buoyancy module are definited. At the same time the research focuses on the method of designing the distributed space of buoyancy module and the amount of the applying buoyancy module, putting forward the capable method. Determining the best distribution spacing of buoyancy module distribution design consider the material costs and the curvature of pipeline; The number of buoyancy module design is conducted with the concept of drift domain to determine the optimal number of applications with maximum value of drift region. Finally, an umbilical cable design project in the South China Sea was accomplished as an example, making an entirely design of the distributed buoyancy module, determining the buoyancy module design for different parts, completing the whole design process, and finish the verification of this design.This research of the dissertation is sponsored by Hi-Tech Research and Development Program of China (863 Program). The topic is important part of this program.