Subsea templates are normally transported to the installation site on the deck of a crane vessel.After being lifted off from the deck,the template is 1)over-boarded from the initial location to the target position by ...Subsea templates are normally transported to the installation site on the deck of a crane vessel.After being lifted off from the deck,the template is 1)over-boarded from the initial location to the target position by the side of the vessel;2)lowered through the splash zone;3)further lowered down to the seabed and 4)finally positioned and landed.All the mentioned phases should be evaluated.Usually,the splash zone crossing phase is taken as the critical phase and analyzed to define the installation weather criterion.The over-boarding phase has not been the focus of analysis due to a large involvement of human actions and little involvement of hydrodynamic effects.During offshore operations,the offshore manager may decide to decrease the defined installation weather criterion if the risk of the personnel safety on deck during over-boarding phase is considered high.Thus,it is of great need to quantify the operational criterion for such operation.The objective of this paper is to perform numerical analyses and define the allowable sea states for a safe over-boarding operation.The numerical analyses using time-domain simulations have been performed in various sea states.Tugger lines have been modelled to control the motions of the template during the operation.The pendulum motions of the subsea template are considered as the critical responses for the assessment of the allowable sea states.展开更多
A subsea flowline jumper （FJ） is a basic connected component for the wet oil tree, subsea pipeline and riser base, and it plays an irreplaceable role in the subsea production system. During the installation of FJ, c...A subsea flowline jumper （FJ） is a basic connected component for the wet oil tree, subsea pipeline and riser base, and it plays an irreplaceable role in the subsea production system. During the installation of FJ, collisions often happen between FJ and other equipment, which may cause serious damage. Besides, as the operating water depth increases, the demand for the installation equipments, such as the crane and winch, will increase. The research of deepwater FJ installation in China is still in the primary stage, thus an installation method for the deepwater FJ is proposed in this paper. Finite element models of a typical M-shaped FJ installation system are built to simulate the installation procedures. Analysis results show that the installation steps designed are feasible and valid for the deepwater FJ. In order to ensure the safety of the installation process, the collision-sensitive analysis for the FJ is conducted, and results show that it is necessary to set the pick up speed at a proper value, in order to avoid collision in the installation process. Besides, the mechanical characteristics of FJ during the installation are investigated under a range of environmental conditions and it is found that the maximum stress of the FJ always happens at its central position. The basic requirements for the installation equipment are also obtained through the analysis of the main installation steps.展开更多
文摘Subsea templates are normally transported to the installation site on the deck of a crane vessel.After being lifted off from the deck,the template is 1)over-boarded from the initial location to the target position by the side of the vessel;2)lowered through the splash zone;3)further lowered down to the seabed and 4)finally positioned and landed.All the mentioned phases should be evaluated.Usually,the splash zone crossing phase is taken as the critical phase and analyzed to define the installation weather criterion.The over-boarding phase has not been the focus of analysis due to a large involvement of human actions and little involvement of hydrodynamic effects.During offshore operations,the offshore manager may decide to decrease the defined installation weather criterion if the risk of the personnel safety on deck during over-boarding phase is considered high.Thus,it is of great need to quantify the operational criterion for such operation.The objective of this paper is to perform numerical analyses and define the allowable sea states for a safe over-boarding operation.The numerical analyses using time-domain simulations have been performed in various sea states.Tugger lines have been modelled to control the motions of the template during the operation.The pendulum motions of the subsea template are considered as the critical responses for the assessment of the allowable sea states.
基金Supported by the Numerical Simulation and Experimental Investigation of FPSO and Offloading System(2011ZX05030-006-002)
文摘A subsea flowline jumper （FJ） is a basic connected component for the wet oil tree, subsea pipeline and riser base, and it plays an irreplaceable role in the subsea production system. During the installation of FJ, collisions often happen between FJ and other equipment, which may cause serious damage. Besides, as the operating water depth increases, the demand for the installation equipments, such as the crane and winch, will increase. The research of deepwater FJ installation in China is still in the primary stage, thus an installation method for the deepwater FJ is proposed in this paper. Finite element models of a typical M-shaped FJ installation system are built to simulate the installation procedures. Analysis results show that the installation steps designed are feasible and valid for the deepwater FJ. In order to ensure the safety of the installation process, the collision-sensitive analysis for the FJ is conducted, and results show that it is necessary to set the pick up speed at a proper value, in order to avoid collision in the installation process. Besides, the mechanical characteristics of FJ during the installation are investigated under a range of environmental conditions and it is found that the maximum stress of the FJ always happens at its central position. The basic requirements for the installation equipment are also obtained through the analysis of the main installation steps.
