Nonlinear Dynamic Characteristic Analysis of a Landing String in Deepwater Riserless Drilling

Table 2

Parameters of landing string and drilling system.

Parameter	Value
Outer diameter	160.96 mm
Inner diameter	131.7 mm
Speed	20–60 rev/min
Drilling pressure	2 T
Elastic modulus	206 GPa
Poisson’s ratio, μ	0.3
Tube density	7846 kg/m^3
Landing string length,	1500 m
Seawater depth	1500 m
Platform movement	1.2 sin (1.0t) m
Near-surface flow velocity,	1.55 m/s
Near-mudline flow velocity,	0.36 m/s
Seawater density	997 kg/m^3
Drag coefficient,	0.7
Added mass coefficient,	1.0
Formation rock density,	2640 kg/m^3
Drill pipe damping ratio,	0.1
Steel-rock friction coefficient,	0.102