Optimization Design of a Riser-Drill String Coupling System Based on CAE Techniques

Table 1

Nomenclature list.

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: Factor of wind speed

: Distance from mud line (m)

: Amplitude of sea wave (m)

: Circular frequency of sea wave ()

: External diameter of riser (m)

: Mass of riser per unit length ()

: Flexural stiffness of drill string ()

: Mass of drill string per length ()

: Top drift of riser ()

: Stiffness of lower joint ()

: Wind speed ()

: Water depth (m)

: Period of sea wave ()

: Drag coefficient

: Sea-water density ()

: Buoyancy factor

: Tension of drill string ()

: Contact stiffness ()

: Amplitude of drill bit ()

: Stiffness of top joint ()

: Current speed ()

: Geographic latitude ()

: Sea wavelength (m)

: Inertial coefficient

: Flexural stiffness of riser ()

: Tension of riser ()

: Gravitational acceleration ()

: Friction coefficient

: Frequency of drill bit ()

: Initial gap between pipes (m)

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