With the rapid development of large-scale development of marginal oilfields in China,simple wellhead platforms that are simple in structure and easy to install have become an inevitable choice in the process of oilfie...With the rapid development of large-scale development of marginal oilfields in China,simple wellhead platforms that are simple in structure and easy to install have become an inevitable choice in the process of oilfield development.However,traditional simple wellhead platforms are often discarded after a single use.In pursuit of a more costeffective approach to developing marginal oilfields,this paper proposes a new offshore oil field development facility—an integrated bucket foundation for wellhead platform.To verify the safety of its towing behavior and obtain the dynamic response characteristics of the structure,this paper takes a bucket integrated bucket foundation for wellhead platform with a diameter of 40 m as the research object.By combining physical model tests and numerical simulations,it analyzes the static stability and dynamic response characteristics of the structure during towing,complete with the effects of the draft,wave height,wave period,and towing point height,which produce the dynamic responses of the structure under different influence factors,such as roll angle,pitch angle,heave acceleration and towing force as well as the sensibility to transport variables.The results show that the integrated bucket foundation for wellhead platform is capable of self-floating towing,and its movement is affected by the local environment,which will provide a reference for actual projects.展开更多
Given the unconstrained characteristics of the multi-robot coordinated towing system,the rope can only provide a unidirectional constraint force to the suspended object,which leads to the weak ability of the system to...Given the unconstrained characteristics of the multi-robot coordinated towing system,the rope can only provide a unidirectional constraint force to the suspended object,which leads to the weak ability of the system to resist external disturbances and makes it difficult to control the trajectory of the suspended object.Based on the kinematics and statics of the multi-robot coordinated towing system with fixed base,the dynamic model of the system is established by using the Newton-Euler equations and the Udwadia-Kalaba equations.To plan the trajectories with high stability and strong control,trajectory planning is performed by combining the dynamics and stability of the towing system.Based on the dynamic stability of the motion trajectory of the suspended object,the stability of the suspended object is effectively improved through online real-time planning and offline manual adjustment.The effectiveness of the proposed method is verified by comparing the motion stability of the suspended object before and after planning.The results provide a foundation for the motion planning and coordinated control of the towing system.展开更多
Air-floating towing beha viors of multi-bucket foundation plat form （MBFP） are investigated with the 1/20-scale model tests and hydrodynamic so ftware MOSES. MOSES numerical model was val idated by test results, and...Air-floating towing beha viors of multi-bucket foundation plat form （MBFP） are investigated with the 1/20-scale model tests and hydrodynamic so ftware MOSES. MOSES numerical model was val idated by test results, and M OSES prototype model of MBFP can eliminate scale effect of model. The influences of towing factors of to wing speed, water depth, freeboard, and w ave direction on air-floating tow ing stability of MBFP were analyzed by model tests and validated MOSES prototype mod el. It is sho wn that the re duction of towing sp eed can effectively d ecrease the to wing force and surge acceleration to improve towing stability. Water depth is another f actor in towing s tability. Obvious shallow water effect will appear in shallow water with sma ll water depth-draft ratio and it w ill disappear gradually and air-floating towing becomes more stable with the increase of water depth. Accelerations of surge, s way and heave are small and they have modest changes when freeboard increases from 0.5 to 2 m. For MBFP, the freeboard is not suggested to be larger than 2 m in following wave. Wave direction has large influence on the towing stability, the surge acceleration and towing force are sensitive to the va riation of wave direction, the surge acceleration and towing force in following wave （0°） and counter wave （180°） are much larger than that in transverse sea （90°and 270°）.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52271287).
文摘With the rapid development of large-scale development of marginal oilfields in China,simple wellhead platforms that are simple in structure and easy to install have become an inevitable choice in the process of oilfield development.However,traditional simple wellhead platforms are often discarded after a single use.In pursuit of a more costeffective approach to developing marginal oilfields,this paper proposes a new offshore oil field development facility—an integrated bucket foundation for wellhead platform.To verify the safety of its towing behavior and obtain the dynamic response characteristics of the structure,this paper takes a bucket integrated bucket foundation for wellhead platform with a diameter of 40 m as the research object.By combining physical model tests and numerical simulations,it analyzes the static stability and dynamic response characteristics of the structure during towing,complete with the effects of the draft,wave height,wave period,and towing point height,which produce the dynamic responses of the structure under different influence factors,such as roll angle,pitch angle,heave acceleration and towing force as well as the sensibility to transport variables.The results show that the integrated bucket foundation for wellhead platform is capable of self-floating towing,and its movement is affected by the local environment,which will provide a reference for actual projects.
基金the National Natural Science Foundation of China(No.51965032)the National Natural Science Foundation of Gansu Province of China(No.22JR5RA319)+1 种基金the Excellent Dectoral Student Foundation of Gansu Province of China(No.23JRRA842)the Science and Technology Foundation of Gansu Province of China(No.21YF5WA060)。
文摘Given the unconstrained characteristics of the multi-robot coordinated towing system,the rope can only provide a unidirectional constraint force to the suspended object,which leads to the weak ability of the system to resist external disturbances and makes it difficult to control the trajectory of the suspended object.Based on the kinematics and statics of the multi-robot coordinated towing system with fixed base,the dynamic model of the system is established by using the Newton-Euler equations and the Udwadia-Kalaba equations.To plan the trajectories with high stability and strong control,trajectory planning is performed by combining the dynamics and stability of the towing system.Based on the dynamic stability of the motion trajectory of the suspended object,the stability of the suspended object is effectively improved through online real-time planning and offline manual adjustment.The effectiveness of the proposed method is verified by comparing the motion stability of the suspended object before and after planning.The results provide a foundation for the motion planning and coordinated control of the towing system.
基金financially supported by the National Natural Science Foundation of China(Grant No.51309179)the National High Technology Research and Development Program of China(863 Program,Grant No.2012AA051705)+2 种基金the International S&T Cooperation Program of China(Grant No.2012DFA70490)the State Key Laboratory of Hydraulic Engineering Simulation and Safety(Tianjin University)the Tianjin Municipal Natural Science Foundation(Grant No.13JCYBJC19100)
文摘Air-floating towing beha viors of multi-bucket foundation plat form （MBFP） are investigated with the 1/20-scale model tests and hydrodynamic so ftware MOSES. MOSES numerical model was val idated by test results, and M OSES prototype model of MBFP can eliminate scale effect of model. The influences of towing factors of to wing speed, water depth, freeboard, and w ave direction on air-floating tow ing stability of MBFP were analyzed by model tests and validated MOSES prototype mod el. It is sho wn that the re duction of towing sp eed can effectively d ecrease the to wing force and surge acceleration to improve towing stability. Water depth is another f actor in towing s tability. Obvious shallow water effect will appear in shallow water with sma ll water depth-draft ratio and it w ill disappear gradually and air-floating towing becomes more stable with the increase of water depth. Accelerations of surge, s way and heave are small and they have modest changes when freeboard increases from 0.5 to 2 m. For MBFP, the freeboard is not suggested to be larger than 2 m in following wave. Wave direction has large influence on the towing stability, the surge acceleration and towing force are sensitive to the va riation of wave direction, the surge acceleration and towing force in following wave （0°） and counter wave （180°） are much larger than that in transverse sea （90°and 270°）.
