A drilling riser is a conduit that provides a temporary extension of a subsea oil well to a surface drilling facility. The drilling risers are used with subsea BOP and generally used by floating drilling vessels. When used at deeper depths, the drilling riser must be tensioned to maintain stability. To reduce the capacity of the tensioner needed to maintain the riser's stability, a buoyancy module is added to the riser to neutralize buoyancy when submerged. And as current flows over the drilling riser, VIV is generated by repeated vortex shedding. Designer can attach a VIV suppression device to prevent excessive fatigue loading by VIV. This attachment is necessary to ensure the stability of the drilling riser, but it also has side effects. In the design of the drilling riser, it is important that the riser offsets occur laterally along the depth when current is applied to the riser and that the clear distance from the moonpool is maintained. Drilling risers also require attention to fatigue and cost. In this paper, we investigated the influence of the attachment, such as the buoyancy and the VIV suppression devices.
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