Hybrid Drilling & Production Concepts for the East Coast - PowerPoint PPT Presentation

Hybrid Drilling & Production Concepts for the East Coast Offshore Prepared for: Calgary SNAME Branch By: John Fitzpatrick CJK Engineering Ltd. May 2008

Overview CJK ENGINEERING East Coast Production Systems Lessons from the Beaufort Sea � Ice Loads � Steel Research Program Steel (Hybrid) GBS Concept Other Steel (Hybrid) Drilling/Production Concepts � Steel GBS for water depths around 140m plus � Semi-Rigid Floating Concept

East Coast Production Systems CJK ENGINEERING There is a perception that concrete GBS’s or FPSO’s are the only feasible production options for the East Coast Offshore.

What About Steel GBS Concepts? CJK ENGINEERING Steel does not spring to mind when considering production concepts for the East Coast Offshore. Reasons for this may include: In the 1980’s, ice loads were thought to be extremely high. Concrete was � considered the best solution and FPSO’s were the only alternative. Unlike the concrete industry, there is no co-ordinated marketing effort � from steel fabricators to engineer and construct a steel GBS. A concrete GBS is thought to maximize the number of construction jobs. �

Lessons From the Beaufort Sea CJK ENGINEERING 30 years of experience in the Beaufort Sea has demonstrated the competitive advantage of bottom-founded steel structures.

MAT Skirt System CJK ENGINEERING 1.0 m 1.0 m

Skirt Detail Show ing Thin Bladed Design CJK ENGINEERING For drainage Bottom Shell 25 mm Pl. 25 mm Pl. 5000 mm

Base Design Criteria CJK ENGINEERING Applied Stress (MPa) 2.0 1.5 Minimum ultimate structural resistance Clay data point 1.0 Plastic failure line, sandy soils (from experience at three sites) Load imparted by contact areas with Cu=2000 psf (uniform) 0.5 Average contact stress 0 30 3 6 9 12 15 18 21 24 27 Square Root of Loaded Area (m)

Full-Scale Steel Test Program (1990-91) CJK ENGINEERING Deflected shape of stiffened plate specimen

CJK ENGINEERING Stiffener Post Yield Failure Response

CJK ENGINEERING EH 36 OLAC Steel Response at -60 c

Scantlings Capable of Carrying 450 psi over 5m by 5m CJK ENGINEERING 25 mm shell Pl . 300 mm x 25 mm } Stiffeners at 1000 mm centers, spanning 5000 mm 450 mm x 25 mm 1000 mm 5000 mm x 1000 mm x 25 mm Typical Panel Typical

Evolution of External Shell Stiffening CJK ENGINEERING “Old code” pre-1985 Thicker Deeper Poor post-yield behavior Smaller Present state-of-the-art Less weight; easier to build; cheaper

Plate and Stiffener Tests CJK ENGINEERING Plating - full scale tests Normal Loading Factor of about 20 compared to wL²/12 Stiffeners – 1/5 scale tests Normal Loading Factor of about 4 compared to F y / √ 3

Patented Structure (Lapsed) CJK ENGINEERING MAIN PARTICULARS Height to Top Deck 130 m Base (octagonal) 125 m x 125 m Base Area 13,000 m 2 Light Ship Draft (including topsides and solid ballast) 60 m Minimum GM 6 m Stable afloat with 30,000 tonnes of topsides at all stages of set down OIL STORAGE Approximately 750,000 to 1 million bbls

Patented Structure (Lapsed) CJK ENGINEERING DESIGN WAVE h = 30 M, WL = 350 m Base Shear 100,000 tonnes Base Moment 5 MM tonne·m DESIGN ICE Iceberg Base Shear 90,000 tonnes Base Moment 6.3 MM tonne·m SOILS - FOUNDATION Friction Angle = 30° or Cu = 125 kPa beneath sand surface. Minimum Effective Contact Force on Bottom = 350,000 tonnes. QUANTITIES 85,000 tonnes EH 36 OLAC steel or equivalent. 130,000 m 2 solid ballast with density of 3 tonnes/m 3

Patented Structure (Lapsed) CJK ENGINEERING

CJK ENGINEERING Compare - Contrast

CJK ENGINEERING Inertia Dominated Wave Force

CJK ENGINEERING Pressure Area Curve

CJK ENGINEERING Fully Engineered & Verified

June 1996 Costs CJK ENGINEERING $750MM (2007 ) � 11 shipyards visited in 1996, including a Canadian yard � Average cost ~ $400 MM (one-third a concrete GBS)

140 Meter Water Depth Height to Top Deck 175 m Steel Grade EH36 OLAC 130,000 tonnes Base (octagonal) 140 x 140 m Concrete Ballast 250,000 m 3 16,000 m 2 Base Area Min. Weight on Bottom 260,000 tonnes Design Wave 27 m Base Shear 100,000 tonnes Min. F.O.S. 1.5 Design Ice 15,000 tonnes Up to 30 m deep ridges, 35 m 4 m thick consolidated layer Max. Water Depth 140 m Internal Water Ballast Level Concrete Ballast -140 m Sand ϕ = 30º; or Clay min. Cu ~ 95 kPa

Variable Water Depth 80 to 140 Meters Min. Weight on Bottom 400,000 tonnes 95 m Design Wave 27 m Base Shear 150,000 tonnes Min. F.O.S. 1.5 Design Ice 20,000 tonnes Up to 30 m deep ridges, 4 m thick consolidated layer Min. Water Depth 80 m Internal Water Ballast Level Sand ϕ = 30º; or Clay min. Cu ~ 140 kPa

Dynamic Response CJK ENGINEERING Typical percentile response of large mass structure w ith minimal damping

“Ringing” CJK ENGINEERING Background and experience slides Typical percentile response of large mass structure w ith significant damping

CJK ENGINEERING Crossover Water Depth

STEPPED STEEL GBS ARCTIC TLP / BUOY STRUCTURE STEPPED STEEL GBS ARCTIC TLP / BUOY STRUCTURE CJK ENGINEERING 135 135 100 100 meters meters 50 50 20 20 meters meters 0 0 0 0 -45 -45 -50 -50

TLP During Relocation CJK ENGINEERING

CJK ENGINEERING FS = 1.3 with 1 m deflection at 15,000 T horizontal load FS = 1.0 with 5 m deflection at 20,000 T horizontal load Up to 30 m deep ridges, 3 m thick consolidated layer 20 m Free Board 27 m wave 30,000 T buoyancy 25 m Draft Water depth range 80 to 400 m 0 50 100 meters Avg. 15,000 T Max. 30,000 T 55,000 T before Cable tensioning 45,000 T after tensioning 32,000 T during load 40,000 T Sand φ = 33º; or Scrap Iron Ballast Clay min. Cu = 80 kPa inside ELEVATION IN 250 M WATER

Plan View After Installation CJK ENGINEERING 3 Steel Base Anchors Plan area 2500 m2 Steel Structure 15,000 T Platform: Iron Ballast 40,000 T Hull Steel Weight 30,000 T Empty & neutral buoyancy during relocation Payload in Transit 15,000 T m 2 Top Deck 8000 Top Deck Diameter 100 m Cable Handling Deck Diameter 70 m Moon Pool Diameter 15 m Water ballasted during anchoring 3 Sets of Cables 45º angle to vertical 120º in plan; Each set: 48 x 90 mm, 890 T Cables 0 50 100 meters TOP VIEW ON OCEAN FLOOR IN 250 M OF WATER

Ice Load Equals 50% Buoyancy, Note Lack of Rotation CJK ENGINEERING

Ice force 15,000 Tonnes, Buoyancy 30,000 Tonnes CJK ENGINEERING Excess Buoyancy Angle of Attack of force on structure or CG1 tensile force in CG2 tensile force in CG3 tensile force in 15,000 tonne ice downwards vertical tonnes. tonnes tonnes force in degrees. component of all three cable groups ‘0’ degrees means Points to the north, Points to 120 Points to 240 Points to 240 ice comes from the for ease of reference degrees degrees degrees south 0 0 21,213 21,213 30,000 (just about to go slack) 10 215 18,979 23,233 30,000 20 853 16,598 24,976 30,000 30 1,895 14,142 26,390 30,000 40 3,309 11,686 27,431 30,000 50 5,052 9,305 28,069 30,000 60 7,071 7,071 28,284 30,000

Non Linear Response CJK ENGINEERING Approximate amount Maximum Cable Excess buoyancy structure would Ice load/ effect Group force in requirement move sideways and tonnes downwards 15,000 tonnes 28,284 30,000 1m/0m 20,000 tonnes 32,998 40,000 5m/3m 25,000 tonnes 40,825 50,000 10m/6m 30,000 tonnes 48,990 60,000 13m /8m

Moon Pool Main Deck Lower Deck Winch Deck Cable Slots Inner Bottom Bottom Anchor Top Iron Ballast Anchor Btm . Skirt Tip ½ INBOARD PROFILE

3 x 16 Reel Sets Serving One Anchor Moon Pool 15 MW Gas Turbine 15 m Dia . & Air Compressor WINCH DECK PLAN 70 m DIA.

Set of Four Cable Reels CJK ENGINEERING EACH REEL: 3.30 M DIA x 1.75 M LONG Cable Slot Underneath PLAN VIEW

Reel Winch Deck Motor Cable Grip -Closed Slot MOORING SYSTEM SCHEMATIC WHILE ANCHORED (N.T.S.) Inner Bottom Bottom Hawser Cable toward Anchor

30,000 Tonne Stiff or Non Compliant CJK ENGINEERING System Under 27m Wave Cost Item Quantity Unit Cost 2006 dollars (MM USD) Upper Hull 40,000 t $3500/t 140 Anchor 1 22,000 t $3000/ t 65 Anchor 2 22,000 t $3000/t 65 Anchor 3 22,000 t $3000/t 65 Steel Ballast (scrap) 240,000 t $250/t 60 Cables 90,000m $1100/m 100 Gas Turbine Compressor 2 40 Spools, Supports and winch motors 144 $200,000 30 Ballasting system for upper hull Item 5 Engineering and approvals Item 30 Hull and anchor assembly and tow to first site. Item 30 Contingency Item 70 Grand Total 700

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