In these Technical requirements the following abbreviations are used:

nebraskaboomOil and Offshore

Nov 8, 2013 (3 years and 5 months ago)

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SCOPE OF WORKS AND
TECHNICAL REQUIREMENTS


On


DISCONECTI
ON

AND RE
-
INSTALLATION DAI HUNG FPU & CALM BUOY
SYSTEM

AT DAI

HUNG OIL FIELD




ABBREVIATIONS

In these Technical requirements the following abbreviations are used:

API

American Petroleum institute

API RP

Recommendation Practice of American Petroleum institute

CALM

Catenary Anchor Leg Mooring

FSO

Floating storage and Offloading Unit

IMO

International Marine Organization

MARPOL

International Convention for the Prevention of Pollution from
Ships

MDB

Mid
-
Depth Buoy

MODU

Mobile Offshore drilling unit

PLEM

Pipeline End Manifold

PVEP

Petrovietnam Exploration and Production Company

PVEP

POC

Petrovietnam Domestics Exploration Production Operating Company
Limited

SEMI

Semi
-
submersible

SOLAS

International Convention for the Safety of Life at Sea

VR

Viet N
am Register

WHP

Wellhead Platform









1.
INTRODUCTION

Dai Hung 01

FPU
and CALM buoy system are operation

in Dai Hung
f
ield. The Dai Hung
f
ield is located in Block 05.1A, approximately
250 km, from the coastline of the South
Eastern Vietnam, and situated in a water depth of 110 m (average). The field is operated by
PVEP

POC
.


Figure
1

Location layout of
Dai Hung Field, Vietnam (Source
-
PVEP database)

Dai Hung 01

FPU, which is connected to
twelve

subsea wells (
eleven

production and one
water injection
)

named 1P, 2P, 3P, 4P, 4X, 5P,
6P/7P,
7X, 8P, 9P, 10P, 12X
)

and WHP DH02
via
28

no of

flexible flowlines

and
13

no of

control
umbilical
.

The risers and umbilical are
arranged
in a lazy
-
S


configuration

using a MDB and are connected to the FPU balcony at the
aft,
forward

and starboard side.

Crude oil is stabilised on the
Dai Hung 01

FPU and offloaded to a FSO vessel

by two no of 6”
flexible risers
, which is moored to a
CALM

buoy.

The
risers and umbilical

are

arranged in two Lazy
-
S configurations including middepth buoys.
This document addresses the flexible riser system comprising:

• Forward
balcony

with 9 slots for:

-

Six no. of 3” risers

-

Three no. of
umbilical

• Aft
balcony

with 12 slots for:

-


Two

no. of 6” risers.

-

Six no. of 3” risers

-

Three
no. of umbilical

-


One of Submarine cable


Starboard

balcony

with
20

slots for:

-

Two

no. of
6
” risers

-

Twelve no. of 3” risers

-

Six no. of umbilical

The
Dai Hung 01
FPU and the CALM
-
buoy are both positioned using mooring systems of
eight lines. The CALM
-
buoy is located approximately 2 km from the FPU (see figure below).

The
Dai hung

01
FPU
and CALM
holds class with Viet Nam Register (VR)
.


Figure
2

General layout of
Dai Hung Field, Vietnam (Source
-
PVEP database)


Figure
3

Overall
P
lan view of
Dai Hung Field, Vietnam (Source
-
PVEP database)

As
to the classification requirements
,
Dai
Hung 01 FPU

and CALM buoy

will have to
disconnect
and towing to
dry

dock for inspection and repair. Expected
time
repair is
September 2014
.

1.1. Purpose

This document presents the
scope of works and technical requirements on disconnection and
re
-
installat
ion Dai Hung 01 FPU & CALM buoy system at Dai Hung oil field and towing
it’s

on
the
towing route

(from Dai Hung field to
Assumed

Dung Quat
shipyard
-

will be confirm

by Company

before signing the Contract
-

and come back)
.

1.2. Area of Operation

The area of
operat
ion
on continental shelf of Vietnam in South China Sea, at
Dai Hung field
and towing
rout
e

from
D
ai Hung field to
Dung Quat

ship
yard
.

1.3.
Pro
gr
ess Description


Dai Hung
-
01 FPU and CALM
-
buoy
system will be disconnect
off Dai Hung field
location
,
towing to Dung Quat Ship yard for
repair & inspection on dock

and further re
-
owing &
installation back onto the
field
location.

1.4. Basic Design Data of FPU & CALM Buoy System

1.4.1. Basic Design Data of
Dai Hung 01
FPU System

1.4.1.1. General

The Dai Hung 01 is a semi
-
submersible vessel of the Aker H3.2 design, with two lower
pontoons carrying the deck on 4 columns per pontoon. One additional buoyancy column is
fitted at the aft side of each of the two pontoons.

Dai Hung 01

FPU

had modified to
suit the
requirements of the Dai Hung field.

Main particulars pontoon length

:

108.2 m

Breadth moulded



:

67.36 meters

Main deck length



:

68.6 meters

Main deck elevation



:

36.6 meters

Main deck breadth



:

60.92 meters

Maximum draught



:

21.3
meters

Lightship weight



:

10715 t

Displacement




:

20543 t

Draft
-

Operational



:

21.34 m

Draft
-

Survival



:

19.51 m

Draft
-

Transit



:

6.7 m

The vertical distance from the edge of the pontoon to seawater level (freeboard) has been s
et
to 1 ft. The vertical distance from the vessel baseline to riser balcony is 7.7 m.


Figure
4
: Dai Hung 01 stern view


Figure 5: Dai Hung 01 starboard view

1.4.1.
2
.
Mooring

systems

Eight (8) mooring chains (98 mm diameter NVK4 RIG, studded) anchor the FPU to the
seabed via 37 t Stevshark high holding power marine drag anchors. The minimum design
breaking strength (MBS) of the mooring chains are 10600 kN.

The length of each of the mo
oring line is 1150 m including the chain contained in the chain
lockers. One 100 m chain section (in the chain lockers) is connected to each of the main
mooring chain segments by a 98 mm kenter
-
link. The eight mooring lines are run by four 300
HP double wi
ldcat winches. The mooring lines are pre
-
tensioned to 70 t at operational draft
(21.34 m)


Figure : 3D general layout of Mooring System of Dai hung 01 FPU


Figure :
L
ayout of
position &
Mooring System of Dai hung

01

FPU

1.4.1.3. Riser systems

The riser system for the Dai Hung FPU comprises
the product flowlines (
3”x
2
6

off

+6”x02
off
), the control umbilicals (12 off)
, the submarine cable (01 off)
and the export risers (
6”x
2
off).

For each well there are two product flowlines in service. Each p
roduction riser one is laid in
an essentially inverted lazy
-
S (or JS) catenary system passes over a mid depth buoy, and
connects to the riser balcony on the DH01.

This inverted lazy
-
S (or JS) layout is a new catenary system developed for the Dai Hung field
.
Whereas a lazy
-
S catenary is laid down in one direction, the JS catenary system used in the
Dai Hung field, reverses direction after the mid depth buoy in order to minimise flowline
lengths to the wellheads. The flowlines to the wellheads near the DH01 F
PU are all dynamic,
whereas the flowlines to the wellheads located more remote from the DH01 FPU comprise
dynamic and static sections.

A single control umbilical is laid parallel with both production flowlines from the DH1 to
each subsea wellhead completio
n.


Figure : 3D general layout of riser system of Dai hung 01 FPU


Figure : Riser position for each balcony of Dai hung 01 FPU


1.4.2. Basic Design Data of CALM Buoy System

1.4.2.1. General

The CALM BUOY: (Catenary

Anchor Leg Mooring Buoy) is located 2.0 km from the DAI
HUNG
-
01 FPU. The CALM BUOY is moored in a 400 tonne capacity mooring yoke
assembly and is equipped with a mooring hawser arrangement designed to moor tankers in
environmental conditions characterised

by a significant wave height of 5.5m.

The Dai Hung
-
01 Calm Buoy mooring system consists of 8 chain/anchor lines locked on the
CALM BUOY chain table by chain wedge stoppers

Principal dimensions and weights of the CALM buoy as below:

Overall height





11.
75 m

Height of main body




6.80m

Skirt diameter





21.3 m

Outside diameter




17.3 m

Draught during Tow




3.3m

Vertical
center

of gravity from bottom

5.10m

Total weight of CALM buoy



458.96 tonnes (metric)

Distance seabed/chain stopper


107.20m

Wei
ght of anchor chains



168t


Figure : 3D general layout of CALM buoy Dai hung

1.4.2.2. Mooring system of CALM buoy

The mooring system consists of eight approx. 728m long stud link chain lines. Each line is
composed of sections of various diameter chains,
i.e. 76mm, 82,5mm and 87mm and is
connected to 20tonne Stevpris drag anchors. The 87mm components are located near the
anchors.

Weight of 76mm and 87mm chain in air and water is given below:


76mm diameter chain:

Weight in Air


: 128kg/m

Weight in Water

: 111kg/m

87mm diameter chain:

Weight in Air


: 171kg/m

Weight in Water

: 149kg/m

Each mooring line is locked on the CALM
-
buoy chain table by chain wedge stoppers. The
mooring lines will be pre
-
tensioned to 259kN (26.4t).

The mooring system spread is
given in below Figure:


Figure : Mooring lines arrangement


Figure : Mooring lines configuration of CALM buoy

1.4.2.3. Export risers system



Figure:
General layout of e
xport riser system

of CALM buoy


Figure: Export riser configuration system


1.5 Codes,
Standards

&
R
egulations


This project shall be based on the following rules and regulations:



TCVN 5309:2001, Mobile Offshore Unit Rules for Classification and Construction


Classification



TCVN 5310:2001, Mobile Offshore Unit Rules for Classific
ation and Construction


Hull



TCVN 5311:2001, Mobile Offshore Unit Rules for Classification and Construction


Equipment Arrangement



TCVN 5312:2001, Mobile Offshore Unit Rules for Classification and Construction


Stability



TCVN 6809
-
2001
:
Rules for the
classification and construction of single point
moorings



TCVN 8403
-

: Rules for the classification and construction of flexible riser



IMO
-
MODU Code 2001



IMO
-
MODU Code 1979



IMO: Code for Construction and Equipment of Mobile Offshore Drilling Units
(MO
DU Code)



International Convention for the Safety of Life at Sea, 1974 (Consolidated Edition
1986)



International Conference on Load Lines. 1966 (1981 Edition)



International Conference on Revision of the Regulations for Preventing Collisions at
Sea, 1972
(2007 Edition)



MARPOL 73/78 (Consolidated Edition 2007)



Requirements concerning Mobile Offshore Drilling Units

IACS



API RP 2SK
:
Recommended Practice for Design and Analysis of Station
-
keeping
Systems for Floating Structures
.



API RP
For flexi



AISC: America
n Institute Steel Constructions



AWS 2006 Structural welding code steel



Final Metocean And Environmental Design Criteria For Dai Hung Field (PVEP)


Wherever the requirements of the above documents are in conflict, generally, the more
onerous criteria shall

be adopted.

2. THE SOLUTION PROGRESS

The solution progress for this project as below:

+ Disconnect flexible riser, umbilical, mooring system of FPU,

+ Disconnect Kamari

FSO
, CALM buoy and theirs system

+ Towing FPU, CALM

buoy

from Dai Hung field to Dung

Quat shipyard
by towing
vessel
for inspection and repair. After the inspection and repair progress
are
finished,
further towing come back to Dai hung field.

+ Re
-
installation FPU, CALM, FSO and theirs system at Dai Hung field
.

FPU deck cranes

can

be applied for flexible risers disconnection/reconnection

at Aft/
Stbd
riser balconies
.

Additional structures/ facilities devices may be applied as necessary.

3
.
TECHNICAL REQUIREMENTS

AND SCOPE OF WORK

The Contractor to provide Lumpsum service and but no
t limited as following requires:

3
.1.
Concept solution and
desi
gn for disconnect, towing & re
-
installation at field

3
.1.1. Concept solution

Carry out
all
the works
and d
efining the
detail concept for the solution progress. D
etails
the
procedure and sequence in the progress.
Prepare Technical Documentation, design and
engineering for
this project
. All the Technical Documentation, design and engineering shall
be developed in compliance with the
solution progress

(
Item 2

of th
is

document
) and the latest
of
Classification Society’s Rules and Regulations as well as the requirements of relevant
applicable international codes and standards. The Technical Documentation, design and
engineering must also be approved by
Third Parties

and the
PVEP POC
;

2.1.2. SOW

The summary scope of works for
engineering for disconnect & reinstallation Dai Hung FPU
and their system
shall be, but in any case not be limited to, the
following:

SOW

for

Engineering Analysis

No

Description

Note

1

Preliminary analysis of mooring system for disconnection


2

Preliminary analysis the methodology for disconnect the flexible riser


3

Preliminary analysis stability and ballast plan for disconnection progress


4

Preliminary analysis the laydown position and laydown zone for each
flexible riser system


5

Preliminary analysis for mattress laydown area on the sea bed


6

Details analys
is the mooring system for disconnection


7

RAO analysis of DH01 FPU


8

Static analysis for flexible riser and umbilical during disconnect & reconnect
progress


9

Dynamics analysis of
flexible riser

& umbilical during connect & disconnect
progress


10

Interaction analysis between flexible riser and DH FPU
for each step


11

A
nalysis stability and ballast plan for disconnection progress


12

Platform position analysis during disconnection


13

Detail o
ffset analysis for platform during disconnection


14

Platform position analysis during disconnection


15

A
nalysis
the h
olding capacity and vessel arrangement
for
towing


16

Details the position of Dai Hung FPU during disconnection


17

Holding capacity and vessel towing arrangement analysis


18

Analysis the e
quipment arrangement for disconnect & connect progress


1
9

Design and arrangement the preliminary equipment
& material (A frame …)
for disconnect & connect progress


20

Strengthen and upgrading Dai Hung FPU for installation
equipment


21

Strength analysis for each types of flexible riser or umbilical during

disconnection

22

Limiting the position and potable offset for each FPU position during
disconnect & connect progress


23

Analysis the laydown position and laydown zone for each flex
ible riser
system


24

Analysis for mattress laydown area on the sea bed


25

Disconnect & Installation limitation analysis


26

Towing arrangement & analysis for transportation of Dai Hung 01 FPU


27

A
nalysis stability and ballast plan for
towing

progress
of Dai Hung 01 FPU


28

Towing arrangement & analysis for transportation of CALM buoy


29

A
nalysis stability and ballast plan for
towing

progress
of CALM buoy


30

MTO for disconnecting
progress


31

MTO for towing
progress


32

MTO for
connecting

progress


33

Conclusion and recommendation



SOW

for

Procedure

& Sequence

No

Description

Note

1

P
rocedure for
prepare the sea bed &
laydown mattress progress


2

P
rocedure for

installation equipment &

material on Dai Hung 01 FPU for
disconnection progress


3

P
rocedure for
disconnection

progress for each flexible riser

system (STDB,
AFT, FWD) and laydown on seabed


4

Procedure for disconnection of mooring system of Dai Hung 01 FPU


5

Procedure for disconnection of Kamari FSO


6

Procedure for disconnection of CALM buoy


7

Procedure for towing Dai Hung 01 FPU


8

Procedure for towing CALM buoy


9

Procedure for re
-
installation Dai Hung 01 FPU at field


10

Procedure for re
-
installation

CALM buoy at field


11

Procedure for connecting progress for each flexible riser system


12

Details sequence for disconnection Dai Hung 01 FPU and their systems


13

Details sequence for disconnection CALM and their systems


14

Details s
equence

for re
-
installation Dai Hung 01 FPU at field


15

Details s
equence

for re
-
installation CALM buoy at field



3
.1.2. Requirements

3
.1.2..1 General

The Contractor shall provide drawings/MTO on fabrication/ installation all the necessary
auxiliary structu
res (gantry/ropes for riser lay down by deck crane, ropes for anchor chain lay
down etc.).

The Contractor shall compose step
-
by
-
step operation diagrams with indication of parameters
necessary for personnel (directions/distances for FPU moves, anchor windl
asses numbers and
pull/pay lengths, crane operations etc.).

Project Program shall consolidate all the procedures and cover all the scope of work.

Each procedure shall contain information covering the following:



what is the aim of operation



what to do, in
what sequence



how to perform non
-
obvious steps which may lead to error/damage.risk for personnel,
what actions are unacceptable



how to ensure the correct/incorrect result is achieved



what to do in case of incorrect result



necessary consumables



necessary eq
uipment/tools



qualification/skills requirements to the team/manager



necessary documents to check before start



documenting work results and remedial actions.

3
.1.2.2.
Visual
Inspection

at field

The constructor
must be visual inspection at Dai Hung field be
fore design the methodology
for disconnect, towing and re
-
installation
.
Before coming to Daihung field for inspection the
contractor’s personnel must have BOSIET (FOET)

and must follow HSE policy on Daihung
Fi
eld.

3
.1.2.
3
.
Working Schedule

and Execution
Plan

The schedule for design and engineering are 5 months
including Third Parties
(
Classification
Society
)

and the PVEP POC
approv
al
;

3
.1.2.
4
. Design/ Engineering Documentation Format

The Contractor shall format the design/ engineering documentation in English: five hard
copies and three copies on CDRoms.

3
.2. Concept solution for disconnect, towing & re
-
installation
progress
at
Dai Hung
field

3
.2.1. Concept solution

The concept solu
tion are according to the procedure and sequence of this project

3
.2.2. SOW

The summary scope of works for disconnect, towing & re
-
installation progress

of
Dai Hung

FPU and their system
shall be, but in any case not be limited to, the following:



Disconnect

Dai Hung 01 FPU: disconnect mooring lines and their flexible riser of
FPU, laydown on the sea bed



Disconnect Kamari FSO: disconnecting from CALM bouy



Disconnect CALM
buoy
: disconnect mooring lines and their export flexible riser of
CALM
buoy
, laydown

on the sea bed



Towing Dai Hung 01 FPU

and CALM buoy from Dai Hung field to Dung Quat
shipyard



Towing back Dai Hung 01 FPU and CALM buoy from Dung Quat shipyard to Dai
Hung field



Reinstallation Dai Hung 01 FPU: connect mooring lines and their flexible rise
r of FPU



Reinstallation CALM buoy: connect mooring lines and their export flexible riser of
CALM buoy



Connect Kamari FSO to CALM bouy

3
.
3
.2. Requirements

Undertake to
disconnection,
transport
ation and reinstallation Dai Hung 01 FPU, CALM and
their system
progress in the safety condition and comply with all the requirements of
classification, administration and owner
.

3
.
3
.2.1.
Trial
a
nd
Inspection

3
.
3
.2.2.

Equipment


3
.
3
.2.3.

Safety

3
.
3
.2.4.

Pollution Preventing


4
. REQUIREMENTS for the PROPOSAL (COMPAN
Y/PERSONNEL)



The Contractor
and their personnel (engineers, project manager) are to be experienced
with similar (more complex) projects at least for 5 latest years.



The engineers
and design
are to have appropriate certificates
of third party and
classification
recognized or any other reputed International Register.



The Contractor to provide using
Suitable Software for the WORK

Appendices:

1.
Daihung field general information

2. FPU
a
nchor
chain p
attern

& configuration

3
. CALM Buoy
a
nchor
chain p
attern

& configuration

4
.
Summary of survey results 2010

5
.
Riser balcony arrangement

6
.
Daihung field general arrangement

7
.
Deck crane operating radius