CENTRE FOR OFFSHORE FOUNDATION SYSTEMS
Introduction to
Offshore Structures Part I
Hodjat Shiri BSc Civil Eng., MSc Geotech Eng. , PhD (curnt.) Offshore Offshore Geotech.
Centre for Offshore Foundation Systems (COFS)
CENTRE FOR OFFSHORE FOUNDATION SYSTEMS
Modern Offshore Structure
Piled-Jacket
TLP
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Offshore Structures are not limited to Platforms •
Vessels and Tankers
•
Sub-Marines & ROVs
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Pipelines
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Sub-sea manifolds
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Bridges
•
Wind Turbines
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Artificial Islands
•
Ports and Jetties
•
…
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“Oil Rocks” The world’s first offshore oil platform built near Baku in Soviet Union, 1949
The first oil platform in the world is the Oil Rocks (Neft Daşlar ı), built near BAKU in Azerbaijan of Rusiia. Building on the platform began in 1949, with Tankers transporting Oil from the first Well to Baku in 1951. The Oil Rocks lies 45–50 km (about 25 nm) offshore on the CASPIAN SEA. The most unique feature of the Oil Rocks is that it is actually a functional city with a population of about 5000. The Oil Rocks is a city on the sea, with over 200 km of streets built on piles of dirt and landfill. Most of the inhabitants work on shifts;
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“Thames Sea Forts” The World’s predecessors of modern offshore oil platforms, having been pre-constructed in a very short time, during World War II , they were then floated to their location and placed on the shallow bottom of the Thames estuary
Installation sequence
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“Maunsell Sea Forts” The World’s first modern offshore platform
The Maunsell Sea Forts were small fortified towers built in the Thames and Mersey estuaries during the second world war to help defend the United Kingdom. They take their name from their designer Guy Maunsell . They were decommissioned in the late 1950s and were used for other activities
CENTRE FOR OFFSHORE FOUNDATION SYSTEMS
Offshore Structures: •
Fixed Structures [ Piled-Jackets, Jackup Rigs, GBS…]
•
Floating Structures [ Spar, TLP, FPSO, SemiSub,…]
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Water Depth •
Shallow waters, D < (300~400 m)
•
Intermediate Waters, (800~1000 m) > D > (300~400 m)
•
Deep Waters, D > 1000 m 3 2 4 m
3 8 1 m
Eiffel, Paris,1889
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Shallow Water Offshore Complex Connection Bridges
Wellhead PLF
Living Quarter PLF
Production PLF
Topside Wellhead PLF
Flare
Jacket
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Jacket Based Platforms
Topside
Jacket
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Platform Compartments
Pedestal Crane Flare HeliDeck Control Unit Top Deck Mezzanine Deck Cellar Deck
Utilities
Conductor Pipes
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Construction Milestones • • • • •
Engineering, Feasibility Study, Conceptual Design, FEED, Basic, Detailed, Shop, Field Procurement: heart of Job Fabrication, Steel Cutting, Fitting, Welding, Erection, Piping, E&I, Safety, Painting… Pre-commissioning, mechanical, E&I, Safety,… Load out & Sea-fastening, Yard Preparation, Barge preparation, Grillage Installation, Barge Mooring, Ballasting, Load Transfer, Sea-fastening, Parking…
• •
Transportation, Pilot Transition, Towing, Field Entering, Positioning… Installation, Barge Approach, Mooring, Sea-Fastening Cut, Lifting or Launching, Stabbing, Welding…
• • •
Hook up, Ship Loosed Items, Caisson, Risers,… Commissioning Start up
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Load Out & Transportation
Pilotage
Open Sea Towing
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Offshore Installation • •
Heavy Lifting by Derrick Crane Barges Floatover by Launch Barges
Topside Lifting
Topside Floatover
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Heavy lifting Derrick Crane Barges •
Revolving Crane Barges
•
Shearlegs
Shearleg
Jacket Revolving Crane
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Platforms Structural Engineering Main Categories : • • • • •
Fabrication Erection Analysis Load-out Analysis Transportation Analysis Installation Analysis In-Place Analysis
In-place Analysis / Environmental Loads • • • • • •
Wind Wave Current Earthquake Ice & Snow Temperature Variations
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Platforms Structural Engineering Design Rules & Codes •
Eurocode 8: "Structures in Seismic Regions - Design", CEN (in preparation).
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API-RP2A, "Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms", American Petroleum Institute, Washington, D.C., 18th ed., 1989.
•
OCS, "Requirements for Verifying the Structural Integrity of OCS Platforms"., United States Geologic Survey, National
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DNV, "Rules for the Design, Construction and Inspection of Offshore Structures", Det Norske Veritas, Oslo, 1977 (with
Centre, Reston, Virginia, 1980.
corrections 1982).
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NPD, "Regulation for Structural Design of Load-bearing Structures Intended for Exploitation of Petroleum Resources",
•
BS6235, "Code of Practice for Fixed Offshore Structures", British Standards Institution, London, 1982.
Norwegian Petroleum Directorate, 1985.
DOE-OG
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End of Part One
Thank You
