TECON provided comprehensive detail design services for the West Franklin and Elgin B offshore platforms, two major installations in the British sector of the North Sea. Working as the primary engineering contractor for Rosetti Marino, under the ownership of TOTAL, this project represented a significant undertaking in offshore oil and gas infrastructure development. The project encompassed the complete engineering design of two sophisticated topsides structures and an inter-platform connecting bridge, all designed to operate in the challenging environmental conditions of the North Sea at water depths of approximately 90 meters.

The complexity of this project stemmed from the need to integrate multiple platform functions including well operations, process facilities, utilities, accommodation, and safety systems while maintaining structural integrity in harsh offshore conditions. The platforms needed to support drilling operations with multiple well slots, house extensive process equipment, and provide safe working environments for personnel. Additionally, the connecting bridge between Elgin B and Elgin A platforms required precise engineering to accommodate structural movements while maintaining operational continuity.

Project Scope

The engineering scope encompassed two distinct topside structures and an inter-platform bridge, each with unique design requirements and functional specifications. The West Franklin platform features a larger configuration to accommodate 12 well slots, while Elgin B supports 9 well slots with a more compact footprint. Both platforms were designed to integrate seamlessly with existing infrastructure while maintaining operational independence.

West Franklin Topside Structure

• Four-leg steel frame structure arranged in a 22.5m x 22.5m square configuration with four longitudinal trusses interconnected by four transverse trusses
• Three main operational decks plus dedicated ESDV (Emergency Shutdown Valve) deck spanning 35.5m x 35.9m
• Integrated helideck for personnel transport and emergency evacuation
• 12-slot well bay with complete wellhead equipment and control systems
• Process facilities including separation, compression, and treatment equipment
• Utility systems encompassing methanol storage and distribution, wash water systems
• High Integrity Pressure Protection System (HIPS) and cold vent facilities
• Temporary refuge (TR) accommodation facility with life support systems
• Local Equipment Room (LER) housing critical electrical and control equipment
• Lifeboat station with launch systems and platform crane for material handling

Elgin B Topside Structure

• Similar structural configuration to West Franklin with main dimensions of 30.0m x 30.0m
• 9-slot well bay optimized for the platform’s production requirements
• Process facilities tailored to Elgin B operational specifications
• Liquid hold-up system and wash water utilities
• Technical building housing control room and equipment spaces
• Lifeboat emergency evacuation system
• Sliding connection point for the ELA-ELB bridge to accommodate thermal expansion and structural movement
• Platform crane for deck operations and maintenance activities

Inter-Platform Bridge

• 96-meter tubular frame steel structure connecting Elgin B to Elgin A platform
• Triangular cross-section measuring 5.0m x 5.0m (width x height) for optimal strength-to-weight ratio
• Designed to accommodate thermal expansion, structural deflections, and relative platform movements
• Integrated utilities and personnel access systems

Engineering Approach

TECON’s engineering methodology focused on delivering robust, code-compliant designs that met all safety and operational requirements while optimizing constructability and lifecycle costs. The design process incorporated advanced structural analysis, comprehensive load case evaluations including extreme weather conditions, and detailed integration studies to ensure seamless connection with existing facilities. All work was executed in accordance with international offshore standards and TOTAL’s stringent technical specifications. The engineering deliverables included complete fabrication drawings, material specifications, welding procedures, and construction specifications to support the fabrication and installation phases of the project.