Targeting Deep Water in the Gulf of Mexico

By: Lars deskaug, Sevan Marine ASA

Sevan FPSO Concept

AGENDA
Track Record
Main Tecnological Features
Application to the Ultra Deep
Waters in the GoM

Page 2

Worlds Growing Fleet of Cylindrical Floaters

5 Floating Production Units
(FPSOs)

Piranema Spirit

Hummingbird Spirit

Voyageur Spirit

Goliat

Sevan Louisiana

Sevan Developer

4 Drilling Units

Sevan Driller

Sevan Brasil

3 Accommodation Units

Arendal Spirit

Page 3

Stavanger Spirit

Nantong Spirit

WIDP

FPSO Piranema Spirit

In operation since October 2007

Field operator:
FPSO owner:
Hull:
Topside integration:
Location:
Water depth:
Hull size:
Oil processing:
Gas process/ injection:

Page 4

Petrobras
Teekay Petrojarl
Yantai Raffles
Keppel Verolme
Offshore Aracaju, Brasil
1000m
Sevan300
30 000 bod. (4800m3/d)
3.6 mill Sm3/d (130 mill
scfd) @ 280 bar

FPSO Goliat

On location in Barents Sea from 2015

Field operator:
Location:
Water depth:
Yard:
Hull size:
Oil processing:
Water injection:
Gas compression:
Oil storage:
Power feed from shore:

Page 5

Eni
Norwegian Barents Sea
400m (Harsh and sub-arctic)
Hyundai Heavy Industries
Sevan1000
100 000 bod (15.900 m3/d)
125 000 bwd (19.900 m3/d)
140 Mill Scfd
1 000 000 bbls (159.000 m2)
60 MW

FAU Floating Accommodation Units

Owned and operated by Logitel Offshore

DESIGN/HULL TYPE
Sevan 300-FAU design
Yard: COSCO Nantong / Qidong
ACCOMMODATION
500 beds in 294 cabins
4 single, 238 double, 4 quadruple
DP SYSTEM
DYNPOS AUTRO (DP3)
Azipod thrusters (underwater detachable) 6 X 4.4 MW
Service Speed
7 knots
Power generation
33 MW

Page 6

Sevan Louisiana

Owner and operator Sevan Drilling

Third Ultra Deepwater MODU

Contracted by LLOG in the US Gulf of Mexico
since 2014
Yard: Cosco Qidong

Page 7

Sevan FPSO Concept

AGENDA
Track Record
Main Tecnological Features
Application to the Ultra Deep
Waters in the GoM

Page 8

Geo-stationary hull
Main benefits

Axio-symetric hull
No weathervaning - Hull facing environment with
same shape in all directions no need to rotate >
Eliminating turret and swivel

WAVES

Capex savings: Cost of turret /swivel and thrusters

avoided
Opex savings: Reducing requirement for marine
crew, fuel consumption, spares
Increased flexibility: Spare capacity for tie ins of
future risers

Sevan shape

Page 9

Insignificant bending stresses

due to global loads on the hull

Eliminating wave induced fatigue loads

Minimal hull deflections (sag/ hog) simplifying topsides interface

Page 10

Lower pitch/ roll motions

leading to reduced fatigue and stress
Roll/ pitch motions
Circular FPSO

Ship-shaped
FPSO
Fatigue

Pitch/ roll motion comparison in irregular

waves: Sevan vs. FPSO and Semi 1)
Sign. roll/ pitch amplitudes
Figures in deg/m
Roll motions
Pitch motions

FPSO

Minimal pitch/ roll

motions
Suitable for
permanent mooring
in any location
Lifetime: > 30
years

Costly turret required

in harsh weather
must weathervane
Higher bending stress
on hull and risers
Lifetime: < 25 years
(Conversions < 15
years)

Sevan
Peak periods (s)

Superior pitch/ roll characteristics leading to improved

uptime and longer lifetime in harsh environments

Page 11

Sevan Hummingbird in Hs=6m

No significant motion response (video)

Page 12

Tuning of hull shape

Motion Optimizations

Page 13

Sevan FPSO Concept

AGENDA
Track Record
Main Tecnological Features
Application to the Ultra Deep
Waters in the GoM

Page 14

RPSEA Hull Selection

indicated as possible concepts are

Ship-shaped FPSO
Non ship-shaped cylindrical FPSO (represented by SEVAN 1000)
Non ship-shaped hemispherical FPSO (represented by SSP 320 Plus)
Deep draft semi-submersible FPSO (represented by Octabuoy 1 MMbbls)

SEVAN 1000 selected for further study!

Basis of Design

Page 16

Field:

Generic, Gulf of Mexico

Water depth:

2,500m

Sea State:

100 yrs (Hs 15.8m, Tp 15.4s)

1,000 yrs (Hs 19.8m, Tp 17.2s)
10,000yrs (Hs 22.1m, Tp 18.2s)

Storage capacity:

1,000,000 bbls

Oil production:

60,000 bopd (+50% future)

Water production:

60,000 bopd

Gas processing:

60 mmscfd

Motions:

Acceptable for Steel Catenary Risers

No. of risers:

11 (not critical for Sevan design)

Field Layout and FPSO Orientation

Page 17

FWPSO
Flexible solution

Mooring lines
Drill pipe

Risers

Template

Hull Design
Main Particulars

Hull Diameter
Bilge box Diameter
Bilge box plate Diameter
Main Deck Diameter
Process Deck Diameter

93
124
138
103
109

m
m
m
m
m

Main Deck El. (Hull depth)

Process Deck El.

42 m
48 m

Draft, Ballast
Draft, Loaded
Freeboard to MD, Ballast
Freeboard to MD, Loaded

22
31
22
11

Topsides Payload
Cargo Oil Storage

Page 19

m
m
m
m

30.000 t
1mmbbls

Motions Model tests of Sevan Hull

Sevan Basin Model Test - Scaled to S1000 Size

30

GoM 1 yr operating

Significant Wave Height, Hs [m]

GoM 100 yr operating

GoM 1000y
1000 yrHurricane
Hurricane

25

2001 SEVAN 300 FPSU

2002 SEVAN 1000 FPSO
20

2004 SEVAN 300 FPSO

2005 SEVAN 300 FPSO
2006 SEVAN 650 MODU

15

2007 SEVAN 300 FPSO

2007 SEVAN 1000 FPSO
2008 SEVAN 1000 FPSO

10

2008 SEVAN 1000 FPU Ice

2009 SEVAN 1000 FPSO

2010 SEVAN 650 SCR FPU

2011 SEVAN 400 FPSO
2011 SEVAN 1000 FSO

0
0

10

15

20

Peak Wave Period, Tp [s]

Page 20

25

30

2013 SEVAN 650 MODU

Motions

Heave motion

Heave Motion

Loaded draft

Ballast draft

Hs
[m]

Tp
[s]

Sign
Amp
[m]

MPM Amp
[m]

Sign Amp
[m]

MPM Amp
[m]

1 yr Operating Condition

3.7

9.1

0.09

0.16

0.14

0.26

10 yr Operating Condition

6.0

11.5

0.27

0.50

0.42

0.78

100 yr Operating Condition

8.0

13.0

0.47

0.86

0.73

1.34

100 yr Hurricane Condition

13.4

14.9

1.12

2.02

1.59

2.89

1000 yr Hurricane Condition

17.0

16.0

1.94

3.46

2.41

4.33

Wave condition

Motions

Heave accelerations

Vertical Acceleration

Loaded draft
Hs
[m]

Tp
[s]

1yr Operating Condition

3.7

10yr Operating Condition

Process Deck Bow

Ballast draft

Sign Amp
[m/s2]

MPM Amp
[m/s2]

Sign Amp
[m/s2]

MPM Amp
[m/s2]

9.1

0.13

0.25

0.22

0.41

6.0

11.5

0.27

0.49

0.39

0.73

100yr Operating Condition

8.0

13.0

0.34

0.64

0.49

0.92

100yr Hurricane Condition

13.4

14.9

0.51

0.95

0.73

1.34

1000yr Hurricane Condition

17.0

16.0

0.60

1.11

0.84

1.56

Wave condition

The most probable maximum vertical acceleration amplitude in the 1.000-year

condition is limited to 0.15g.
Motion sickness is no issue even in the worst hurricane conditions.

Mooring System
Layout

Typically 15 lines in three clusters

Anchor
158 mm R4S bottom chain
270 mm lower polyester rope
Connection element
270 mm Upper polyester rope
158 mm R4S Top chain

Page 23

Mooring System
Calculations

Safety factors according to API RP 2SK:

Page 24

Mooring System
Offset

Offsets are calculated for in-line, in-between and at an intermediated heading

Offset

100y Cond.

1000y Cond

Page 25

Offset (% of water depth)

Offset (% of water depth)

Ballast Condition

Loaded Condition

Direction

In-line

Intermed.

In-Betw.

In-line

Intermed.

In-Betw.

Heading*

+/- 30

+/- 60

+/- 30

+/- 60

Static

1.4

1.9

2.2

1.3

1.8

2.1

LF

1.3

1.6

1.9

1.0

1.3

1.4

WF

0.3

0.3

0.3

0.3

0.3

0.3

Tot

2.9

3.7

4.3

2.5

3.2

3.6

Allowed

5.0

5.0

5.0

5.0

5.0

5.0

Static

2.7

4.0

4.4

2.5

3.7

4.2

LF

1.7

2.1

2.5

1.3

1.6

1.8

WF

0.4

0.4

0.4

0.4

0.4

0.4

Tot

4.7

6.3

6.9

4.1

5.6

6.3

Allowed

7.0

7.0

7.0

7.0

7.0

7.0

Hull Design
Tank Arrangement
WB Tanks

Outer Cargo Tanks

Inner Cargo Tanks

Cofferdam

Page 26

Topside Layout

Payload capacity 30.000t

Accommodation
Process area

Moonpool

Lifeboats
Offloading

Blast wall

Page 27

Moonpool Arrangement

Offloading

Accommodation

Bilgebox

Mooring lines

Risers

Page 28

Offloading and Export

Destinations
LOOP

Lower Tertiary

Any US Port: Handysize (330,000 bbls)

Export:

Up to VLLC

LOOP:

Suezmax or VLLC

Example: Lower Tertiary - LOOP

Assumed sailing time to LOOP: 15 hrs.

Unloading at LOOP:

30 hrs.

Sailing from LOOP to FPSO:

15 hrs.

Connect, offload, disconnect:

30 hrs.

Total:

90 hrs.

Offloading

Elongated sector allows for near 360

degrees operation (DP Tankers)
Distance between the shuttle tanker bow
and FPSO: 200-250m
Green Sector 30m wide
Yellow Sector 10m wide

Offloading with HiLoad

Source: Remora

Page 31

HiLoad Arc Loading System

FPSO Support Vessel

Constant 20-30 ton pull

DP Station Keeping of Tanker

by HiLoad
150 ton bollard pull

Conventional Jones Act Tanker

Sevan FPSO

Page 32

Crude Transfer Vessel "CTV"

Based on proven Technology

Courtesy of Cefront
Conventional Loading System, similar to Bow Loading System (BLS)
Conventional Offloading reel with floating hose located on aft deck (SDS)
Mooring hawser for keeping tanker in position

Booster pump for high cargo transfer rate

Distance between the FPSO and the CTV same as for DP shuttle- tanker operation.
Distance between CTV and tanker same or larger than for CALM Buoy
Total separation between FPSO and tanker larger than for DP shuttle-tanker operation

Targeting Gulf of Mexico

Hull fabrication at COSCO (Qidong) Offshore Co., Ltd.

Transportation friendly

The completed unit may be dry

towed (long distance on a heavy
lifter)
or wet towed with full crew on
board

Heavy lifter 13-14 knots

Towed at 7 knots

Topsides and Integration on the Gulf Coast

Picture courtesy of Kiewit

Thank you

Page 38