Research For Installation Of A Top Tensioned Riser For A Tensioned Leg Platform

The developments of deep water oil and gas industry promote the development of deep water riser installation technology, and make it the front of scientific and technological innovation. Through the learning from foreign experience in engineering practice and foreign advanced deepwater riser installation technology, this paper analyze the top-tensioned riser installation method based on the tesioned leg platform.Environment and operation are the most important factors for riser installation analysis. Environment factor include water depth, wave, current and wind, hydrodynamic loads produced by wave and current action are the most important loads for riser installation analysis.Operation factor must according to actual project to consider things from every angle, include typical process of installation, varying conditions at the top of riser, platform motion and so on. This paper is based on actual project, and then reasonably simplifies boundary conditions at the top of riser. During assembly of stands compersator is disconnected, the top boundary conditions of the riser can be seen fixed, other times regard as pinned.In accordance with the installation process, this paper also reasonably assumes three typical installation cases, splash zone Case, seabed case and installed case. Meanwhile, through analysis regars seabed case with the riser top is fixed as the most dangerous state.The riser withstands the normal operation effects of various loads during installation. The deeper water environmental conditions are more hostile, making installation dependent on environmental conditions significantly enhanced, the limit weather windows to meet the operating time is greatly reduced. This paper uses the riser analysis sofrware Orcaflex to create riser intallation models with high probabilities and short return period's loads, and then determine the limit weather windows.In addition, according to above conclusion of installation analysis, this paper through the using the C++Builder 6.0 and OrcaFlex developed a riser installation program.