Located in the South China Sea where the average water depth is 1,500 meters, the Liwan 3-1 field is the first deepwater oil and gas field in China. The field has proven gas reserves of 100-150 billion cubic meters, with an annual output of 5-8 billion cubic meters. China National Offshore Oil Corporation retained Offshore Oil Engineering Co., Ltd., to perform detailed design for the CNY 1.2 billion Liwan 3-1 natural gas center platform and submarine pipeline.
For analysis and design of the fifth largest jacket structure in the world, the company applied the automated load transfer capability between MOSES and SACS to replace the usual manual transference of loads for analysis. The jacket, which was 189.5 meters deep, with a 201 meter erection height, and weighed 31,126 tons, was modeled using SACS. Gravity and environmental loads were applied in SACS, and the jacket structure was then imported into MOSES for launch analysis. The subsequent loads at various time steps were then imported into the structural model for strength checking using the interface between the two software tools.
Manual strength analysis would have taken several people dozens of days to complete, and often not without errors. Using Bentley’s automated technology, strength analysis was completed by one person in less than two days. The technology reduced project delivery time by one month and reduced costs by CNY 10 million.
Traditional strength analysis for jacket launch and installation would have been too time-consuming and repetitious. Using SACS and MOSES, Offshore Oil Engineering developed an intelligent automated launch strength analysis technique that automatically analyzed the strength of the jacket during the launch sequence. The technique improved design quality, reduced errors, decreased man-hours, and shortened construction time.