Journal of Ocean Engineering and Technology (한국해양공학회지)

Korean Society of Ocean Engineers (한국해양공학회)
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Study on Moonpool Resonance Effect on Motion of Modern Compact Drillship

  • Yang, Seung Ho (Department of Naval Architecture and Ocean Engineering, Pusan National University) ;
  • Yang, Young Jun (Department of Naval Architecture and Ocean Engineering, Pusan National University) ;
  • Lee, Sang Beom (Department of Naval Architecture and Ocean Engineering, Pusan National University) ;
  • Do, Jitae (Department of Naval Architecture and Ocean Engineering, Pusan National University) ;
  • Kwon, Sun Hong (Department of Naval Architecture and Ocean Engineering, Pusan National University)
  • Received : 2013.04.10
  • Accepted : 2013.06.10
  • Published : 2013.06.30
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Abstract

A drillship is a representative floating offshore installation. The boom in oil and gas field development has dramatically increased the demands for drillships. Drillships have a moonpool in the center area of the ship for the purpose of drilling. This moonpool has an effect on the seakeeping performance of a drillship in the vicinity of the resonance frequency. Because of the moonpool, drillships act in different resonance modes, called the sloshing mode and piston mode. The objective of this study was to find the moonpool effect on the motion of a drillship through the motion analysis of a currently operating modern compact drillship. The predicted resonance frequencies based on Molin's theoretical formula, Fukuda's empirical formula, and BEM-based numerical analysis are compared. The accuracy of the predictions using the theoretical and empirical formulas is compared with the numerical analysis and evaluated. In the case of the piston mode, the difference between the resonance frequency from theoretical formula and the resonance frequency from the numerical analysis is analyzed. The resonance frequency formula for more a complex moonpool geometry such as a moonpool with a cofferdam is necessarily emphasized.

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References

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Cited by

  1. Hydrodynamic Study on Water Column Oscillation of Varying Cross-Sectional Moonpool and Its Effect on Resistance of a Drill Ship vol.140, pp.3, 2018, https://doi.org/10.1115/1.4038396