METHOD FOR THE EXPANSION ESTIMATION OF AGED SUBSEA PIPELINE AND RISER TO PREVENT STRUCTURAL BENDING AND BUCKLING COLLAPSE

摘要

The present invention relates to a method to predict an expansion amount of a structure used for underwater oil well development to produce oil and gas and, more specifically, relates to a method to predict the expansion amount to block bending, deformation, and buckling collapse of an offshore structure such as an underwater pipeline and a rise or the like to naturally be deteriorated during the designed service time with the effects of high temperature and high pressure. Moreover, the method to predict the expansion amount of an offshore structure comprises: (a) a step of identifying and inputting various design factors of an offshore structure such as a pipeline installed in the sea; (b) a step of calculating a variable related to the expansion of the offshore structure, and clearly identifying each variable; (c) a step of estimating the expansion amount and a length of a virtual expansion limit anchor as information obtained through step (a) is correlated with a variable obtained through step (b); (d) a step of estimating (screening) a probability of an initial buckling occurrence based on the calculated expansion amount; (e) a step of determining whether the estimated result is sensitive to the buckling phenomenon, and to model the undersea shape through a nonlinear finite element method if it is sensitive, otherwise to finish the design if it is not sensitive; and (f) a step of determining that a post-buckling state is satisfied with safety based on the modeled undersea shape.