Abstract
Mooring systems play an important role for semi-submersible rigs that drill in deepwater. A detailed analysis was carried out on the mooring of a semi-submersible rig that conducted a trial well drilling at a deepwater location in the South China Sea in 2009. The rig was 30 years old and had a shallow platform with a designed maximum operating water depth of 457 m. Following the mooring analysis, a mooring design was given that requires upgrading of the rig’s original mooring system. The upgrade included several innovations, such as installing eight larger anchors, i.e. replacing the original anchors and inserting an additional 600 m of steel wires with the existing chains. All this was done to enhance the mooring capability of the rig in order for the rig to be held in position to conduct drilling at a water depth of 476 m. The overall duration of the drilling was 50 days and the upgraded mooring system proved to be efficient in achieving the goal of keeping the rig stationary while it was drilling the trial well in the South China Sea. This successful campaign demonstrates that an older semi-submersible rig can take on drilling in deep water after careful design and proper upgrading and modification to the original mooring system.
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Yongfeng Guo is a senior engineer for China Oilfield Services Limited; and he acquired his master degree in mechanics of drilling from Beijing Petroleum University in 1994; he went to Norway for studying and visiting in 2004, 2005 and 2006; he majored in the offshore petroleum development, special in the developing of oilfield in deepwater since 2000. He had published a book on drilling engineering of offshore, and was invited to attended conferences in America, Indonessia, Portugal, and had the lecuture in these conferences.
Shaojun Ji is a senior engineer for China Oilfield Services Limited. She graduated from China University of Petroleum, major in mechanical engineering. Her current research interests include deepwater drilling deveice in China offshore, etc.
Changquan Tang is a senior engineer for China Oilfield Services Limited. He graduated from China Jianghan Petroleum Institute, major in petroleum logging. His current research interests include deepwater drilling deveice in China offshore, etc.
Jiansong Li is a manager of vessel department of the China Oilfield Services Limited, and a senior engineer. He graduated from Jimei vessels college of China, major in vessel driving and managing in the sea. His current research interests include achoring of vessel during operation in deepwater in South China Sea, etc.
Huiquan Zhong is a manager of vessel department of China Oilfield Services Limited and a senior engineer. He acquired the master degree from Wuhan University of Technology and graduated from Dalian Maritime University, major in vessel management in the sea. His current research interests include achoring of vessel during operation in deepwater in South China Sea, etc.
Ong Chin Yam Ian is the Executive Director of Franklin Offshore Group of Companies in Singapore and he acquired the Bachelor of Engineering in Mechanical Engineering (Honors) at the University of Glasgow of United Kingdom. He took part in the project of the ASDD trail well of COSL in the South China Sea in 2009 and was charged of installing anchoring for the semi submerisble rig of NH5.
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Guo, Y., Ji, S., Tang, C. et al. Analysis and design of trial well mooring in deepwater of the South China Sea. J. Marine. Sci. Appl. 11, 222–227 (2012). https://doi.org/10.1007/s11804-012-1126-1
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DOI: https://doi.org/10.1007/s11804-012-1126-1