Session: 02-10-02 Collision and Crashworthiness 2

Paper Number: 78952

78952 - Risk Assessment of Collision Between Dynamically Positioned Vessel and Offshore Installation 

DP vessels are serving offshore installations for various purposes, but they may also bring major accident risk during the operation if a collision between vessel and installation happens. A quantified collision risk assessment methodology for DP vessels visiting offshore installations is developed in this paper. The methodology is based on the risk assessment framework defined in ISO31000:2018, and it consists of three elements: risk identification, risk analysis in terms of collision likelihood and collision consequence, and risk evaluation. The methodology accounts for the physics of DP vessels, the reaction time characteristic of human operators and other aspects in position loss and collision scenarios. The likelihood of collision and the consequence of collision, in terms of exceedance probability distribution of impact energy relevant for collision damage, are interrelated and calculated by using a Monte Carlo simulation model. The methodology provides a more accurate risk picture and better support for risk treatment than the collision risk study purely based on the historical collision frequency and the historical collision energy distribution. For risk evaluation the methodology proposes an alternative way of presenting the risk results in terms of “Risk Density”. It is essentially an hourly, instead of yearly, averaged risk level during the marine operation. It helps better visualization and communication of the collision risk between vessel and installation. A case study is presented to illustrate the methodology and concept. It assesses the collision risk between a DP shuttle tanker and an FPSO during offshore loading operations.

Presenting Author: Nils Hasund Vysus Group Norway

Authors:

Haibo Chen Vysus Group Norway
Bjørn Nygård Equinor
Nils Hasund Vysus Group Norway