Sea trial investigation for dynamic load compensation effect evaluation on novel soft hang-off system

ABSTRACT

Offshore drilling activities have been significantly impacted by extreme storm conditions as oil and gas development has moved into deeper water. Under the situation of the imminent arrival of a typhoon, retrieval of the whole drilling riser is time-consuming and tedious. A novel soft hang-off system under hang-off and transit operations is proposed and developed to solve the low-efficiency and time limitation for risers' retrieval. The hang-off joint system suspends the drilling riser and the hydraulic system is designed for dynamic load compensation. Sea trial for enhanced hang-off mode with hang-off joint, non-differential control dynamic load compensation mode at hang-off operation and passive compensation mode at transit operation are conducted to evaluate the load compensation effect equipped with novel soft hang-off system compared with conventional hard hang-off mode. Results on dynamic load compensation effect are discussed. The novel soft hang-off system is of high application value for deepwater drilling engineering.

KEYWORDS:

• Deepwater drilling riser
• novel soft hang-off system
• hydraulic control mode
• sea trial
• dynamic load compensation

Acknowledgments

The authors thank Liangbin Xu, Leixiang Sheng, Chaowei Li, Jian Liu, Mengbo Li from CNOOC Research Institute Ltd., Xiuquan Liu, Yanwei Li from China University of Petroleum (East China), Tingting Li from 2H Offshore Engineering, and Yisong Zhou from Wuhan Lidi Hydraulic Company.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Natural Science Foundation of China [grant numbers 52004325 and 51809279]; National Key Research and Development Program of China [grant number 2017YFC0804500]; National Science and Technology Major Project of China [grant number 2016ZX05028-001]; CNOOC Comprehensive Research Project [grant numbers YXKY-ZX042020 and CCL2017SKPS0147].