Offloading operation bivariate extreme response statistics for FPSO vessel.

Area of Science:

• Ocean Engineering
• Naval Architecture
• Marine Hydrodynamics

Background:

• Floating Production Storage and Offloading (FPSO) units are vital for offshore crude oil production and transport.
• Accurate prediction of dynamic hawser tensions during offloading is a critical design concern for FPSO safety.
• Current industry practices often use uncoupled univariate methods, potentially leading to suboptimal design points.

Purpose of the Study:

• To present an efficient and accurate method for estimating bivariate extreme hawser tension statistics for FPSO units.
• To validate the proposed method through numerical simulations and experimental data.
• To improve the selection of design values for FPSO hawser systems, minimizing damage risks.

Main Methods:

• Utilized AQWA hydrodynamic software to analyze vessel dynamic response to wave loads under realistic sea states.
• Developed and applied the bivariate Average Conditional Exceedance Rate (ACER2D) method for statistical estimation.
• Validated the ACER2D method's performance against experimental data.

Main Results:

• The ACER2D method accurately estimates bivariate extreme value probability distributions and return period contours.
• The method efficiently utilizes available data to provide two-dimensional probability contours for low return periods.
• Numerical simulations and experimental validation confirmed the ACER2D method's efficiency and accuracy in predicting extreme contours.

Conclusions:

• The ACER2D method offers a superior approach to traditional univariate methods for FPSO hawser design.
• This approach enables the determination of bivariate design points, enhancing safety and reliability.
• The proposed method can significantly minimize potential hawser damage in FPSO operations.