TY - GEN
T1 - Evaluation of drag coefficient variation in transit mode on leg & spud can of DP Jackups vessel
AU - Thulkar, Nitin D.
AU - Yamaguchi, Satoru
N1 - Publisher Copyright:
Copyright © 2018 by the International Society of Offshore and Polar Engineers (ISOPE)
PY - 2018
Y1 - 2018
N2 - The Marine and Oil & Gas industries have increased interest in Self Propelled DP Jackups vessel to enhance the overall operational efficiency. The self-propelled jackups vessel has numerous applications such as well intervention, wind farm installation, repair, accommodation, service etc. in this cost optimization process. However due to closed proximity of operation (i.e. near to hydrocarbon platforms or other offshore assets), it has gigantic risk during the Simops Operation. The Simops Operation of Dynamic positioning and Jacking operation has a grey area in force calculations for DP system on board which use mathematical model. The input from position reference sensors, environmental sensors to calculate relative position based on position, heading, speed and rate of turn inputs for station keeping/ DP intended operation and finally issue thrust output command. The system continues to monitor the position by taking its feedback and comparing with calculated vessel position. However, many DP jackups does not have system for hydrodynamic force measurement of leg & spudcan. This is mainly due to drag coefficient of complex leg and Spud Can geometry. The drag coefficient plays vital role in force calculation and due to non-standard shape currently industries follow approximation method. This will increase risk in station keeping under different condition and failure cases. The intension of this study is to find the gap in existing force calculation, which is affected by drag coefficient. During the CFD analysis evaluation the effect of marine growth, leg shape, spud can, leg transit speed under variable environmental conditions are considered. The software use for CFD analysis is Ansys Aim. The vessel data used for the simulation purpose are from most popular design of jackups vessel used in offshore O&G and wind farm industry. The study will provide drag coefficient variation in transit time domain, which has large impact on force calculation estimation for DP System.
AB - The Marine and Oil & Gas industries have increased interest in Self Propelled DP Jackups vessel to enhance the overall operational efficiency. The self-propelled jackups vessel has numerous applications such as well intervention, wind farm installation, repair, accommodation, service etc. in this cost optimization process. However due to closed proximity of operation (i.e. near to hydrocarbon platforms or other offshore assets), it has gigantic risk during the Simops Operation. The Simops Operation of Dynamic positioning and Jacking operation has a grey area in force calculations for DP system on board which use mathematical model. The input from position reference sensors, environmental sensors to calculate relative position based on position, heading, speed and rate of turn inputs for station keeping/ DP intended operation and finally issue thrust output command. The system continues to monitor the position by taking its feedback and comparing with calculated vessel position. However, many DP jackups does not have system for hydrodynamic force measurement of leg & spudcan. This is mainly due to drag coefficient of complex leg and Spud Can geometry. The drag coefficient plays vital role in force calculation and due to non-standard shape currently industries follow approximation method. This will increase risk in station keeping under different condition and failure cases. The intension of this study is to find the gap in existing force calculation, which is affected by drag coefficient. During the CFD analysis evaluation the effect of marine growth, leg shape, spud can, leg transit speed under variable environmental conditions are considered. The software use for CFD analysis is Ansys Aim. The vessel data used for the simulation purpose are from most popular design of jackups vessel used in offshore O&G and wind farm industry. The study will provide drag coefficient variation in transit time domain, which has large impact on force calculation estimation for DP System.
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M3 - Conference contribution
AN - SCOPUS:85053473186
SN - 9781880653876
T3 - Proceedings of the International Offshore and Polar Engineering Conference
SP - 1314
EP - 1321
BT - Proceedings of the 28th International Ocean and Polar Engineering Conference, ISOPE 2018
PB - International Society of Offshore and Polar Engineers
T2 - 28th International Ocean and Polar Engineering Conference, ISOPE 2018
Y2 - 10 June 2018 through 15 June 2018
ER -
