In order to reduce the dynamic loads on risers under harsh sea conditions and enhance their adaptability to complex marine environments, a multifunctional suspension system for deepwater riser was proposed, which included a suspension system, a hydraulic compensation system, and a measurement and control system, in order to ensure the safety of the suspended riser under severe sea conditions such as typhoons in the South China Sea. In addition, the system can also be applied to transit with a suspended riser between wells, which can significantly reduce the load of the suspension riser. The suspension system suspends a single bearing riser system, and relieves the stress concentration on the top of the riser by means of a centralizer and a hinge joint; the hydraulic compensation system adopts three working modes of differential throttling compensation, passive non-throttling compensation and throttling shielding to meet the requirements of platform avoidance and inter-well transit. The measurement and control system monitors and warns in real time, regulates and controls the telescopic movement of the hollow hydraulic cylinder, and realizes the real-time compensation of the dynamic load of the riser system. The system has undergone sea trial applications, the results show that the proposed multi-function suspension system can significantly reduce the riser top stress and dynamic load amplitude, especially in the differential throttle compensation and passive non-throttle compensation modes. At the same time, the downstream and upstream speeds of the platform are increased to 1.0 knots, which significantly improves the operation efficiency. The system helps to overcome the challenge of traditional suspension mode, provides a safe and efficient solution for deepwater drilling riser operations, and reduces the disaster risk of suspension riser under extreme sea conditions such as typhoons.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |