Development and sea trial investigation for deepwater drilling riser specialized soft hang-off system during transit

Abstract

Offshore drilling activates have been significantly impacted by severe weather conditions as oil and gas development has moved into deep and ultra-deep water. Under the situation of imminent arrival of a typhoon, emergency retrieval of the whole drilling riser is time consuming and tedious. A novel specialized soft hang-off system to improve the adaptability of the drilling riser system under hang-off or transit operations is developed to solve the low-efficiency and time limitation for retrieval all drilling riser joints during extreme storm environment. The specialized soft hang-off system improves its bending capacity and reduce the risk of interference with diverter housing and moonpool and partially compensate the heave motion of drilling platform, to ensure the drilling riser keep lower tension and not compression during hang-off or transit mode. A numerical solution with mechanical model, boundary condition, results validation is conducted and transit operation window is obtained. Sea trial investigation on the novel specialized soft hang-off system during transit operation are conducted to evaluate the performance on global strength and dynamic load compensation effect. The research can be a significant basis and of valuable reference for deepwater engineering and the manufactured novel specialized soft hang-off system is an important emergency equipment.