Conceptual Design Essentials Of The Stinger For Deepwater

Submarine pipelines are very important to ensure normal operation of offshore oil and gas field. Since the first submarine pipeline was laid in 1950s, the requirements of laying water depth increases fast as the exploitation of oil and gas continues deep water trend. Although the laying of submarine pipelines has reached close to 3000 meters in worldwide, the current situation in China remained at less than 150 meters. In order to exploitation the rich oil and gas resources in South China Sea, deep and ultra deep water pipelay technique has become one of the priorities of China's current offshore technology research.Deep water pipeline installation is usually performed by specialized lay vessel. There are several methods to install a pipeline, the most common methods being S-lay and J-lay. Despite only J-lay method was thought to be suit for deep water traditionally, S-lay has its own advantages such as installing pipelines more fast and suit for both deepwater and shallow water. With the development of technology, the pipeline installation depth is increasing quickly, and keeps the depth record of pipeline installation (as of 2005). It can be assumed that S-lay method will be the trend of deep water pipeline installation.Stinger, as one of key equipments of S-lay, is mainly used to control the curvature of the pipe when it leaves off the vessel. Developing a good stinger will increase the laying water depth, laying speed and laying security much. In the past studies, stinger is often idealistic treated as part of circle to be displacement boundary, which is not only affecting the accuracy of analysis but also can not be used for stinger design. This thesis firstly introduce four main types of method for submarine pipelines installation, point out the importance of pipelines installation analysis for design and upgraded stinger in S-lay, then based on basic control equations of pipelines installation, analyzed the factors of S-lay, and specified the conceptual design essentials of the stinger for deepwater S-lay and design flow has been proposed. An approach to obtaining these conceptual design essentials of the stinger has been developed by ABQUAS, and a practical stinger verified the feasibility. Finally, advices on conceptual design of a novel deepwater stinger and upgrade of a stinger have been provided as a favor of decision-making.The last part give the main conclusion of this dissertation and further work in designing deepwater stinger is suggested.The research of the dissertation is sponsored by the Hi-Tech Research and Development Program of China (863 Program, 2006AA09A105-4).