Feasibility Study of a Module Lifting Operations

Feasibility Study: Lifting Two Accommodation Modules Onto Skarv FPSO

Overview

Engineering IDS performed a feasibility study for AkerBP to evaluate the safe lifting of two 50-tonne accommodation modules onto the Skarv FPSO. The study focused on assessing environmental conditions, optimizing lift arrangements, and determining vessel headings to ensure safe operations in the splash zone.

Objective

Evaluate the feasibility of lifting a 50-tonne module onto an FPSO, identifying limiting environmental conditions and optimizing vessel operations.

Scope of Work

Assess environmental conditions and operational limits for safe lifting.

Evaluate relative motions and velocities between crane tip and landing frame.

Determine the optimal vessel headings for lift operations.

Methodology

The analysis adhered to industry standards using advanced hydrodynamic and motion modeling tools:

1. Standards:
   • The analysis adhered to DNV RP-C205 and DNV RP-N103.
2. Hydrodynamic Models:
   • Models of Skarv FPSO and Edda Freya were created using RAOs and scaled reference vessels.
3. Dynamic System Analysis:
   • The complete system, including vessel motion and wave interaction, was analyzed in OrcaFlex.

Results

Sea State Limitations:

Established operational limits for lifting operations based on DP capabilities and motion constraints.

Enhanced Safety:

Recommendations for bumpers and guiding systems improved operational feasibility.

Optimal Vessel Headings:

Identified headings to reduce risk and ensure safe operations.