Dynamic analysis of drillship under extreme metocean hurricane condition in ultra-deep water

Dynamic analysis of drillship under extreme metocean hurricane condition in ultra-deep water

Drillships are used for exploratory drilling operations in a water depth above 3000 m. Design variants in the new-generation drillships include flexible internal storage and payload capacity. While their operations are quite satisfactory in moderate weather conditions, response under metocean hurric...

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Bibliographic Details
Published in:Journal of marine science and technology Vol. 28; no. 4; pp. 784 - 803
Main Authors: Chandrasekaran, Srinivasan, Sharma, Rajiv, Selvakumar, N. Muthu
Format: Journal Article
Language:English
Published: Tokyo Springer Japan 01-12-2023
Springer Nature B.V
Subjects:
Automotive Engineering
Deep water
Deformation
Design
Drilling
Drillships
Dynamic analysis
Engineering
Engineering Design
Engineering Fluid Dynamics
Environmental conditions
Exploratory drilling
Far fields
Heaving
Hurricanes
Mechanical Engineering
Movement
Offshore
Offshore Engineering
Oil and gas exploration
Original Article
Parameter identification
Pitch (inclination)
Rolling motion
Sea state
Sea states
Stability analysis
Water depth
Weather
Structural motion
Drillship
Dynamic analysis
Steady drift forces
Response analysis
Hydrodynamic diffraction analysis
Ultra-deepwater
Finite element analysis (FEA)
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Summary:Drillships are used for exploratory drilling operations in a water depth above 3000 m. Design variants in the new-generation drillships include flexible internal storage and payload capacity. While their operations are quite satisfactory in moderate weather conditions, response under metocean hurricane conditions to preserve operation versatility poses challenges. The design and operation of drillships, which are intricate and domain-specialized vessels, need attention. This study examines the motion characteristics of a drillship for different sea states and environmental conditions. Their stability across critical sea states is also assessed. Based on the numerical studies, it is seen that they experience a modest degree of instability due to excessive roll and pitch under extreme environmental loads. While preliminary checks under mild heave motion showed that the coupled heave–pitch motion dominates the design shear and longitudinal bending, they are critically influenced by the pitch motion. The forces of second-order steady drift in the far field and the near field are compared in the frequency domain. This study identifies parameters that influence its strength and stability, and the results are useful for improving the operational safety and reliability of drillships under challenging offshore conditions.
ISSN:0948-4280
1437-8213
DOI:10.1007/s00773-023-00957-2