BW Pioneer,

Første FPSO i US Gulf of MexicoUtfordringer og løsninger

Oslo, 27. mai 2099

FPSO conversions / Inocean recent projects

Knock Nevis FSOMaersk, Qatar

4.200.000 bbls storageSpread mooring

Knock Allan FPSOCanadian Natural Resources,Gabon, West Africa

25.000 bopd oil capacity1.300.000 bbls storageSpread mooring

Knock Adoon FPSOAddax Petroleum, Nigeria,West of Africa

60.000 bopd oil capacity1.700.000 bbls storageSpread mooring

Aker Smart 1 FPSOReliance Industries Ltd. India

1.200.000 bbls storageTurret mooring

MPF01 FPDSOPetrobras, Black Sea

3.000m drilling wd1.000.000 bbls storageDP unit

DeepProducer FPSO DPFPSOcean

380.000 bbls storageDP unit

BW Offshore / Inocean recent projects

Inocean SOW – Documentation deliverables

Reports for class review and approval :

• Design basis & design brief etc

• Ultimate (ULS) and Fatigue (FLS) structural design report

• Stability book; intact and damage stabililty

General drawings for class review and approval

• General arrangements drws

• LQ incl. haz.area / fire and safety plan

Main structural drawings for class review and approval

• Structural Drawings (Midship section etc

• Topside and supporting structure (process modules, flare tower etc.)

• Structural categories

Marine P&ID & D&ID system drawings for class review and approval

• Ship systems incl ballast & bilge, fire & deluge etc

Contract BWO & PAI (Petrobras America Inc)

• 3Q 2007 contract signed BWO & PAI

• First FPSO in GOM on US Side

• Start Operation January 2010

• Vessel shall be able to operate for at least 8years uninterrupted

Field; Cascade Chinook

BW Pioneer FPSO

• LOA 241m

• LPP 232 m

• BM 42 m

• DM 20,4 m

• Draft 13,9 m

RULES / REGULATIONS

LAW / RULESOuter Continental Shell Lands Act

USCG AuthoritiesHull / Structure

MMS AuthoritiesTopside (Hydrocarbon)

Classification SocietyDNV

Petrobras America Inc GTD(General Technical Description /

Requirements

Design Basis Vessel Conversion

Global strength: Wave loads basedon 20 years return period

Local strength: Wave loads basedon daily return period

North Atlantic environmentSimple formulae for wave bendingmoment (IACS prescriptiveformulae)

Tanker Rules FPSO Standard

Global strength: Wave loads based on 100years return period

Local strength: Wave loads based on dailyreturn period

Designed for specified geographical area.Direct calculation of wave loads

KEY Challenges for BW Pioneer

• ULS (Ultimate Limit State for Hull and Deck Modules & Equipment)

• FLS (Fatigue Limit State for Hull)

• ALS (Accidental Limit State for Hull)

• Marpol Damage Hull

ULS (Ultimate Limit State) for hull

Operational mode – connected to STP bouy

• Vessel shall be able to remain connected to STP buoy for conditions upto and including a 100-year winter storm (Hs = 7.3m)

• Presence of eddy current means beam seas can not be excluded, i.e.headings ranging from head seas to beam seas

Disconnect case – Sail away from impending hurricanes

• Sailing ship – rules for ships may apply (ww or local wave climate?)

(headings 0 – 360 degrees for design loads)

ULS - Green water on deck

Issues:• Low freeboard at full draught• Non-colinear wind/waves/current

Motion & Model test:• Revealed green sea to be a concern

Schematic of selected model test run

ULS (cont.)

Possibility of beam seas leads to large transverse and vertical accelerations

Transverse accelerations ULS [m/s2]

Location Head sea± 30º

Head sea± 90º

Flare tower 3.8 7.6

Deck module 2.4 4.9

Helideck 2.3 5.8

Topside design – integrated analysis

Large accelerations (similar magnitude as North Sea) required integrated analysis

Topside design

GTD requirement for z-quality for all structure in laminar tension

FLS Methodology

Trading tanker / consumed fatigue life

• Inspection of vessel

• Mapping of historic damages

• Basis for selection of consumed fatigue assessment methods

(Nauticus Hull Fatigue vs Stochastic Fatigue)

Historic trade and damage assessed by Nauticus Hull Fatigue

• Fatigue calculations for typical ballast and full load conditions based onprevious sailing history

• Different operational environments included by scaling of fe-factor (refDnV 30.7) Period Sailing route

1992 to 1994 Caribbean – US Gulf1995 - 1996 Far East – Australia1997 – 1999 Caribbean – US Gulf2000 - 2003 Europe and Mediterranean2003 - 2004 Caribbean – US Gulf

2004 - 2004 Europe2004 - 2007 Caribbean – US Gulf2009 - Permanently located as FPSO at Walker

Ridge location

FLS Methodology – Future fatigue damage FPSO

Requirements from client GTD

Specified heading profile

25% head seas

50% quartering seas

25% beam seas

Normal Requirements

Specified heading profile

head sea +/- 30 deg

FLS FEM – global structure and local SCF

Local SCF model

Full stochastic FLS is time consuming

Finite element modelling

• 14 local SCF models at side longitudinals

• 2 of stringer connetions

• 1 on hopper connection

Large amount of data

• 2.5 Tera Byte with analytical data (2500 Gbyte)

• 64b Finite Element solver (Sestra ) - custom setup from DnV for Inocean

1 year calculation periode

FLS summary

• Conversion projects differ from newbuilding since structure already hasdemonstrated its actual fatigue performance (trading as tanker)

• Identification of critical details - with high confidence level

• Required design fatigue life as FPSO is 16 years included DFF of minimum 2on all details

• Details of stiffeners connection to bhd was improved in waterline area

• Relatively long design life as FPSO, with limited possibilites of repair,necessitate thorough fatigue analysis

ALS – Accidental Limit State

Additional concerns that must be designed for (ALS cases) :

• Sudden hurricanes – vessel unable to escape hurricane

• Loss of heading control or power while escaping hurricane

• Probability of occurrence to be less than 10-4

MARPOL REGULATIONS / DAMAGE HULL

Side damageLong. Extent: The smaller of or 14.5 m (Here 12.5 m)Transv. Extent: The smaller of or 11.5 m (Here 8.40 m)Vert. extent: From base line with no limit

MARPOL REGULATIONS / DAMAGE HULL

Raking bottom damageLong. extent: 0.6 L from the FP (Here 138 m)Transv. extent: B/3 anywhere (Here 14 m)Vert. extent: Breach of the outer hull

PAI Requirements

Side shell structure, in supply vessel mooring area, shall be

checked to ensure that the hull integrity will not becompromised due to vessel boat operations. The loads to beconsidered are those imposed by a 5.000 dwt supply vessel