Application of DOE Methodologies to the FEA of a Payload Suspended on Drill Pipe from a Semi-Submersible Drill Rig

摘要

In the development of a subsea well, one key phase is the lowering of the Xmas tree (XT) from a semi-submersible drill rig to the wellhead on the seafloor. A typical operation involves multiple steps and finite element analysis (FEA) is widely used to model and analyze the operation. The results would help to determine acceptable weather windows. Current practice is to build a system model in the FEA software of choice, and run load cases consisting of variables such as wave height, wave period, current velocity, pipe contents and rig heading. The purpose of this paper is demonstrate how the application of Design of Experiments (DOE) methodologies can streamline the FEA process while giving deeper insight into system behavior, and providing a logical basis for the daunting task of QA checking a large FEA. As an added benefit, the DOE methodology, through response surface modeling, allows the creation of a predictive numerical equation using a multiple regression model. The regression model can be used to calculate realtime operating windows, as well as provide a quick way to handle last-minute equipment swaps without the need to repeat huge amounts of FEA.