A multibody system including a drilling riser system,tensioners and a floating platform is key equipment for offshore oil and gas drilling.Most of the previous studies only focus on the drilling riser system rather th...A multibody system including a drilling riser system,tensioners and a floating platform is key equipment for offshore oil and gas drilling.Most of the previous studies only focus on the drilling riser system rather than the multibody system.Mechanical characteristics of the deepwater drilling riser system cannot be analyzed accurately in a simplified model.Therefore,a three-dimensional multibody analysis program is developed.The static and dynamic characteristics of the deepwater drilling riser system under different platform motions are analyzed based on the developed program.The results show that the static displacement of the riser system with tensioners is smaller than that without tensioners,which means the tensioners can suppress the deformation of the riser system.Under surge and sway motions of the platform,the dynamic displacement of the riser system with tensioners is also smaller than that without tensioners due to the tensioner suppression effect.Besides,the heave motion induces a uniform axial vibration of the riser system,while roll and pitch motions excite the riser system to vibrate laterally.Compared with the stress amplitude due to surge and sway motions,the stress amplitude of the riser system due to heave,roll and pitch motions is relatively small but cannot be neglected.展开更多
Internal solitary waves(ISWs) contain great energy and have the characteristics of emergency and concealment. To avoid their damage to offshore engineering, a new generation of monitoring and early warning system for ...Internal solitary waves(ISWs) contain great energy and have the characteristics of emergency and concealment. To avoid their damage to offshore engineering, a new generation of monitoring and early warning system for ISWs was developed using technologies of double buoys monitoring, intelligent realtime data transmission, and automatic software identification. The system was applied to the second natural gas hydrates(NGHs) production test in the Shenhu Area, South China Sea(SCS) and successfully provided the early warning of ISWs for 173 days(from October 2019 to April 2020). The abrupt changes in the thrust force of the drilling platform under the attack of ISWs were consistent with the early warning information, proving the reliability of this system. A total of 93 ISWs were detected around the drilling platform. Most of them occurred during the spring tides in October–December 2019 and April 2020, while few of them occurred in winter. As suggested by the theoretical model, the full-depth structure of ISWs was a typical current profile of mode-1, and the velocities of wave-induced currents can reach 80 cm/s and30 cm/s, respectively, in the upper ocean and near the seabed. The ISWs may be primarily generated from the interactions between the topography and semidiurnal tides in the Luzon Strait, and then propagate westward to the drilling platform. This study could serve as an important reference for the early warning of ISWs for offshore engineering construction in the future.展开更多
基金This work was financially supported by National Natural Science Foundation of China(Grant No.51809279)Major National Science and Technology Program(Grant No.2016ZX05028-001-05)+3 种基金National Key R&D Program of China(Grant No.2017YFC0804500)Program for Changjiang Scholars and Innovative Research Team in University(Grant No.IRT14R58)the Fundamental Research Funds for the Central Universities(Grant No.20CX02302A)the Opening Fund of National Engineering Laboratory of Offshore Geophysical and Exploration Equipment(Grant No.20CX02302A)。
文摘A multibody system including a drilling riser system,tensioners and a floating platform is key equipment for offshore oil and gas drilling.Most of the previous studies only focus on the drilling riser system rather than the multibody system.Mechanical characteristics of the deepwater drilling riser system cannot be analyzed accurately in a simplified model.Therefore,a three-dimensional multibody analysis program is developed.The static and dynamic characteristics of the deepwater drilling riser system under different platform motions are analyzed based on the developed program.The results show that the static displacement of the riser system with tensioners is smaller than that without tensioners,which means the tensioners can suppress the deformation of the riser system.Under surge and sway motions of the platform,the dynamic displacement of the riser system with tensioners is also smaller than that without tensioners due to the tensioner suppression effect.Besides,the heave motion induces a uniform axial vibration of the riser system,while roll and pitch motions excite the riser system to vibrate laterally.Compared with the stress amplitude due to surge and sway motions,the stress amplitude of the riser system due to heave,roll and pitch motions is relatively small but cannot be neglected.
基金funded by the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) (GML2019ZD0307)the Marine Geological Survey Program of China Geological Survey (DD20190218, DD20221706)+1 种基金the Key Program of Marine Economy Development Special Foundation of Department of Natural Resources of Guangdong Province (GDNRC [2020] 043)the National Natural Science Foundation of China (41806074, 41730528)。
文摘Internal solitary waves(ISWs) contain great energy and have the characteristics of emergency and concealment. To avoid their damage to offshore engineering, a new generation of monitoring and early warning system for ISWs was developed using technologies of double buoys monitoring, intelligent realtime data transmission, and automatic software identification. The system was applied to the second natural gas hydrates(NGHs) production test in the Shenhu Area, South China Sea(SCS) and successfully provided the early warning of ISWs for 173 days(from October 2019 to April 2020). The abrupt changes in the thrust force of the drilling platform under the attack of ISWs were consistent with the early warning information, proving the reliability of this system. A total of 93 ISWs were detected around the drilling platform. Most of them occurred during the spring tides in October–December 2019 and April 2020, while few of them occurred in winter. As suggested by the theoretical model, the full-depth structure of ISWs was a typical current profile of mode-1, and the velocities of wave-induced currents can reach 80 cm/s and30 cm/s, respectively, in the upper ocean and near the seabed. The ISWs may be primarily generated from the interactions between the topography and semidiurnal tides in the Luzon Strait, and then propagate westward to the drilling platform. This study could serve as an important reference for the early warning of ISWs for offshore engineering construction in the future.