China
Africa
Explore chapters and articles related to this topic
Natural Gas
Published in Anco S. Blazev, Energy Security for The 21st Century, 2021
On top of the blowout preventer, a special “marine riser,” a long pipe, is raised to the drilling platform above. It houses the drill bit and drill-string. It is flexible enough, via slip and ball joints, to accommodate the shifting of the drilling platform.
A stochastic analysis approach for marine riser’s cross-flow/in-line VIV under heave-induced parametric vibration
Published in Ships and Offshore Structures, 2022
Zhiwen Wu, Hongyuan Dong, Huihuan Ma, Pengpeng Ni, Yangyang Xiao, Guoxiong Mei
Marine riser is a critical component to transport oceanic gas and oil from the seabed to a platform or a vessel. With the rapid development of deep-water exploration technologies, marine risers have been applied extensively all over the world. The safety and the stability of marine risers are extremely vital for the normal production operation. In deep seas, due to complex marine environmental excitations, such as ocean waves, currents, earthquakes, etc., the risk of fatigue damage becomes severe for marine riser, which could lead to increased potential of structural failure. Thus, it is imperative to assess the safety of marine riser under complex environmental excitations during its service life.
Internal laminar flow effect on the nonlinear dynamic response of marine risers under uniform ocean current
Published in Ships and Offshore Structures, 2021
Yuchao Yuan, Hongxiang Xue, Wenyong Tang
As one of the key parts in the offshore oil and gas production system, a marine riser plays a crucial role in transporting crude oil and natural gas resources from seabed wellhead to the floating platform. Due to harsh operating environment, marine risers always suffer from diverse external and internal excitations, and then experience complicated dynamic response. With the excitation of external ocean current, vortices are generated and alternately shed around the riser, leading to periodic hydrodynamic forces and resultant vibration i.e. Vortex-induced Vibration (VIV) of slender riser. Especially if the frequency of vortex-induced hydrodynamic force is close to structural natural frequencies, a significant vibration of the riser will occur i.e. lock-in phenomenon, accompanied by a non-negligible structure fatigue threat. Several relevant research studies have been carried out to broaden the understanding of VIV (Bearman 2011; Liu et al. 2020). With the excitation of internal fluid flowing, the dynamic stability issue of riser comes out and has been attracting lots of focus. Housner (1952) investigated the internal flow effect on the bending vibrations of a simply supported transverse pipeline, whose axial tension is uniform along the pipeline span, and found the flowing fluid inside the pipeline makes the structural natural frequency decrease and when the internal flow velocity rises to a critical value, the pipeline may suffer dynamic divergent instability, similar to buckling. Païdoussis (2014, 2016) gives a systematic elaboration regarding fluid-conveying pipeline dynamic, combined with massive in-depth studies by his team and other existing research studies over the recent decades. In fact, VIV and internal flow effect on bending vibration of marine risers both belong to typical fluid-structural interaction problems, and each of them is still challenging and worthy of continuous attention.