0
research-article

EQUILIBRIUM POSITION ANALYSIS FOR OFFLOADING OPERATIONS WITH TURRET-MOORED FPSO

[+] Author and Article Information
Alex S. Huang

Universidade de São Paulo, Av. Professor Mello Moraes, 2231, São Paulo/SP, Brazil, Zip-Code: 05508-030
alex.huang@usp.br

Felipe M. Moreno

Universidade de São Paulo, Av. Professor Mello Moraes, 2231, São Paulo/SP, Brazil, Zip-Code: 05508-030
felipe.marino.moreno@usp.br

Eduardo Aoun Tannuri

Universidade de São Paulo, Av. Professor Mello Moraes, 2231, São Paulo/SP, Brazil, Zip-Code: 05508-030
eduat@usp.br

Joselito G.A. Câmara

PETROBRAS/Shipping New Operations Development, Av. Henrique Valadares, 28 , Centro − Rio De Janeiro/RJ, Brazil, Zip-Code: 20.231-030
joselito.camara@petrobras.com.br

1Corresponding author.

ASME doi:10.1115/1.4042531 History: Received July 07, 2018; Revised December 30, 2018

Abstract

With the expansion of oil exploration in deep waters, assessing the risks associated with offloading operations becomes essential in preventing accidents that may cause huge environmental disasters. In this paper, it will be studied the system composed of a turret-moored FPSO connected to a conventional shuttle tanker which is assisted by a tug boat to maintain its position during an offloading operation. Using environmental data collected over a period of 6 years, from 2004 to 2009, from the Campos Basin in Brazil, it was calculated the equilibrium positions of the system considering its constraints (operational criteria defined by Petrobras), and verified the stability of those equilibrium points. The hydrodynamic and aerodynamic static forces were calculated using models validated in the literature. Dynamic effects and oscillations are taken into account by adding safety margins to the operational sectors. With this analysis we calculated the FPSO heading probabilities during an offloading operation and the expected downtime of operation in Campos Basin. We concluded that the downtime of the offloading operation with a conventional shuttle tanker is close to that with a DP shuttle tanker (10% downtime). Furthermore, the results from the stability analysis were used to generate a simplified set of rules to classify the environmental conditions into four classes of operational risk by applying an unbiased decision tree. This method obtains practical rules based on measurements of wind, wave and current, allowing the operator to quickly evaluate the risk level before starting the operation.

Copyright (c) 2019 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Tables

Errata

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In