In recent years, scholars have performed many studies on the installation of the tree, most of which consist of engineering application reports and installation process or method studies, but mechanics analyses have not been frequently reported. Therefore, in this paper, we choose installation of the tree lowered by a drill pipe (hereafter referred to as the pipe) as the research object. In addition, the cost of using drill pipes, including maintenance costs, is quite low compared with those of the riser and winch. The conventional procedure with drill pipes is still widely used because this method sharply decreases the running time. Three methods are available for installation of the tree: winch, conventional completion riser, and drill pipe. Therefore, it is necessary to analyse the motion characteristics for installation of the tree, which is important for higher safety reliability in subsea conditions.
From shallow to deep water, the cost of the underwater equipment has not significantly increased, but the installation cost and installation risk have risen rapidly due to the complex combination of wave and current. With the rapid development and exploitation of offshore oil and gas from shallow to deep water regions, the subsea Xmas tree (hereafter referred to as the tree) is a key piece of equipment in the subsea production system and is widely used in deep water.
The viable towing speed is chosen by discussing the total stress of the drill pipe with various towing speeds and is notably useful for installation in the real sea state. The results show that all factors have remarkable effects on stress and deformation and that the wave height has a lesser effect on the deformation of the drill pipe. Factors that affect the installation process are discussed, such as current velocity, wave height, pipe size, and towing speed.
#Riser analysis tool orcaflex software
In addition, Orcaflex software is applied for simulation, and the simulation results are compared with the results from proposed method, which demonstrate the model and the method accuracy. The research results indicate that the maximum response occurs at 0 radians in the scope of 0 to 2 π, and the quasistatic nonlinear analysis is analysed at 0. The wave phase is selected as one of the variable parameters for analysis of the deformation and stress of the drill pipe. To analyse the stress and deformation of a drill pipe during the lowering of a subsea Xmas tree, a mechanical analytical model and equation were established based on Euler-Bernoulli beam theory.