the design and installation of the buchan field subsea equipment

8/9/2019 The Design and Installation of the Buchan Field Subsea Equipment

1/10

EUR

7

THE DESIGN

ND INST LL TION OF THE UCH N

FIELD

SU SE EQUIPMENT

by

D.B.L.

Walker

P Trading

Limited

EUROPE n

OFFSHORE

PETROLEUM

conFEREnCE

EHHI ITIOn

©

Copyright 198 European Offshore Petroleum Conference and Exhibition

This paper was presented at the European Offshore Petroleum Conference

and

Exhibition held In London England October21·24 1980 The material Is subject tocorrection by the author

Permission to copy isrestricted to

an

abstract

not more than 300 words

ABSTRACT

This paper cover s

th e d es ign and

installation of

the Buohan Field subsea equipment

inoluding:

template, trees and completions, wireline

r iser

and BOP staok, subsea manifold, flowlines and

umbilioals, produotion

riser

and oontrol system.

A brief desoription

of th e

rig modifioat ions to

enable

i t

to

handle

t he produot ion

riser is also

inoluded.

INTRODUCTION

The

Buohan Field l ies in

b look 21/1 of

the

North

Sea, 160 km

eas t-north-east of

Aberdeen.

The

water

depth is between 112 and 118 m and environmental

oonditions

are similar

to those exper ienoed

in

the

Forties

Field whioh l ies

55 km further to

the

east.

With estimated

reooverable

reserves of

only

50 million bar re ls o f

oil ,

however, Buohan is a

twentieth

of

the

size of i ts

giant

neighbour.

An eoonomio evaluation indioated

that

the

Field

was too sma ll to be

exploited

along oonvent ional

l ines,

suoh

as

a

fixed

platform

tied in to

the

Forties

pipeline.

The development had

to

be on a

relatively

short

time

soale requ iring

low

oapital

investment.

The reader

is

d ireo ted to Referenoe 1

fo r a review of

the

alternative

sohemes oonsidered

by

th e Company.

Field

development is based on

produotion

from

subsea wells

to

a oentral underwater

manifold.

A semi-submersible drilling

rig,

oonverted to

oarry produotion

equipment, is

permanently

anohored ove r t he manifo ld to whioh i t

oonneots

by

a produotion

riser.

Multiple

lines in

the

riser bundle

oarry the

oil

up to

the rig for

prooessing and baok

down

to the

seabed fo r

export.

A pipeline t ies th e manifold into a C LM tanker

loading buoy.

When

bad weather

fo ro es th e

tanker

to

stop

loading,

produotion

oeases. f oonditions

oontinue

to

worsen,

then

th e

produotion

ris er is

designed to be reoovered and staoked on

board

th e

rig until

the

weather improves.

275

With this basio oonoept, BP farmed

into

the

Buohan

Field in July 1977 and with a 54 interest beoame

th e

operator.

Plans were

developed fo r

a peak

produotion

from 8

subsea

wells of 72,000

bbls

pe r

day

with

an expeo ted f ield

l i fe of

5 years. Based

on a oomputer simulation

of

f ield operation, i t was

estimated that produotion oould be maintained for

65

of

the yea r, g iv in g an average annual

produotion

rate of 48,000

bbls per day. The

rig

has 3 ,500

bbls

of

storage

whioh

improves

th e

system

performanoe.

With a

gas/oil

ratio

of 56

310

sof/bbl

exoess

gas

will

be flared

on

th e

r ig.

Provision has

been

made

to introduoe a gas l i f t

system

to boost

produotion

as reservoir

pressure

deolines.

Figure 1 i l lustrates th e Buohan

Field.

Five

of

th e

wel ls a re o lu st er ed t og et he r direotly under th e

rig to faoil i tate workover s ee F igure 2 . Two

s te l l i te wells

l ie

1. 7 km to

the south

and

provision

has

been made

fo r

a

third.

Preliminary

field development

plans were based on

an

18 month rig oonversion programme November

1977

to

May

1979 and a

oonourrent

19 month

drilling and

well oompletion

pha se . F lowline

construotion was soheduled for summer 1979

with

produotion

star ting in th e autumn of that

year.

THE SUBSEA TEMPLATE

To

meet

t hi s t ar ge t i t

was

obviously essential

to

build and insta l l

the dr i l l ing template

for

the

cluster

of

subsea wells as rapidly as possible

during

the

summer

of

1977, to

enable produot ion

dr i l l ing to

prooeed

over

th e following

months.

References and

i l lustrat ions

at end of paper.


2/10

The

template therefore had to be simple and

easily

fabricated. Since

th e

layout of

th e

wells had no t

been d ec ide d, t he t em pl at e had to provide a number

of d r il li n g s lo t s with th e facili ty to

support

th e

flowlines.

An 8 s l o t t em pl at e w it h a 5. 2 m spacing between

well

centres

was chosen as shown in Figure

3.

With

th e

underwater manifold occupying one

slo t, . th ere

was p ro vi si on f or 5 template wells with 2 spare

slots in case drilling was abandoned on any

location. The template rested on th e seabed on

aO.65 mwide

s k i r t

round t he base Of each

1.22 m diameter conductor

guide.

The

structure

was held in place by four 12 inch 300 mm

pi n

piles. Provision was made to jack t he t em pl at e

up on i ts

piles to

maintain i t level

in

t he e ve nt

of

a sloping or uneven seabed.

The

90

tonne template was taken ou t

to

th e field

on

a

flat

top barge and

lif ted

into

th e

water

by

a

crawler

crane

on

th e deck

of

a large supply

vessel. t was winched down to

th e

seabed where

divers confirms i ts orientation and position,

some 7 m from an existing exploration

well, later

to be tied in as a

producer.

The

piles

were

driven

using a small underwater v i b r o ~ h m m e r

No

levelling

was reqUired and

th e

template was

secured to th e piles by th e inflation of

annular

packers. Installation

time

was

4 days.

Design, fabrication and

installation

of th e

template took a to tal 01 4 months. SUbsequent

d rill in g and construction work has

validated

th e

basically

simple concept and i f

th e structure

were redesigned today, very few modifications

would be

introduced.

COMPLETIONS ND

TREES

Immediately following template installation in

August 1977, drilling commenced·on th e 4 template

wells. This extended

over the next 14

months,

which also

included

th e

setting of 90

m of 30

inch (760 mm conductor to

ac t

as a foundat ion

for the underwater manifold.

The

wells were

temporarily

suspended pending delivery

of

th e

subsea trees.

Simultaneously two satell i te wells were drilled

by a second r ig during 4 months in th e summer

of 1978. By mOdifying th e original programme

of

5

template

w el ls p lu s

one

southern

s a t e l l i t e

to

become

4 template plus

two

satellites (one

of which

was drilled

back

into

th e central

formation) th e d rill in g schedule was maintained.

The layout of t he t em pl at e

wells,

manifold and

th e off-template well is

shown

in

Figure

2.

C on tr ac ts f or

th e

trees, hangers and

associated

downhole equipment were placed in February 1978

and f irs t

deliveries

were made to

th e

rig in

December of

th e same

year. With a

closed in

wellhead pressure close to 5,000 ps i

34 MPa ,

10,000 psi (68 MPa rated equipment was specified.

The completion had to

provide

fo r

th e

introduction

of

gas l i f t a t some future date by wireline

intervention only and had to be capable of being

used

in

both

perforated

i.e.

previously

tested)

276

and unperforated wells. A nominal 4 x 2 inch

(100

mm

x 50 mm dual completion was

specified

with each string carrying a

su rf a ce c o nt r ol l ed

down-

hole

safety

valve In the case of

th e

4

production

string, this

is

a

tubing

retrievable

valve, with the facili ty in case o f f ai lu re to

be permanently locked ou t and replaced by a

wireline

retrievable unit. For the operation

of

th e

gas l i f t

t he t ub ing string

has been provided

wi th side pocket mandrels

into

which gas

l i f t

valves can be

introduced

by wireline. In

th e

case of satell i te w el ls , t he se gas l i f t valves

ar e already in place. This, i t is hoped, will

avoid th e need to bring in a workover rig to

install them d ur in g t he commissioning of th e gas

l i f t system.

Two types

of

subsea dual tUbing hangers were used.

A hydraulically se t hanger was used on the converted

production well, p ro vi di ng t he

facilities fo r

hanger

setting

and simUltaneous

wireline

access

to both bores with one

multi-purpose

hydraulic

setting tool. The hangers used on

th e

other wells

relied on

being mechanically set with

d r i l l

pipe,

using a second purpose-built aCCess

tool

fo r

wire-

line and testing purposes.

Dual bore split trees were used, shown schematically

in Fi gu re 4. Each tree weighs 52 tonnes and was

installed

as a single

unit. The

lower

tree contains

a dual manual master

v al ve b lo ck ;

th e upper

carries

a six valve block - 2

master,

2 wing, and 2 swab

all hydraulically operated and fit ted with

e x te r na l p o si t io n

indicators. A by-pass loop

carrying

a further 3 valves i s mounted on th e

lower tree and provides

th e

link between

th e

dual

4

inch

flowlines

back

to the

manifold

and the

upper

tree.

Prior

to introducing gas l i f t t he by- pas s val ve

can be

lef t

open to all ow b ot h flOWlines to carry

o il and

to

p er mi t p ig gi ng to remove wax

deposits.

In

th e

event

of major equipment failure, th e upper

tree

can be recovered leaVing th e lower half in

place.

This would r eq u ir e d iv er

intervention

to

break th e connector, flow loop flanges and.

control

circu its.

As each tree became available, th e wells were

re-entered, th e completions run and t he w el ls

perforated, using

one

.rig

a t

th e

template

location

and one

over

th e

satell i te

wells.

Total

time

spent on t he se o p er a ti on s fo r

th e

4 template and

1

off-template

wells amounted to 9 months and 3

months

fo r

th e

two

satell i te

wells.

WIRELINE

BOP ST CK

Following t he r un ni ng of th e

tree, a ll

further

wireline

work

was

conducted through a custom

b u ilt

wireline BOP

stack

mounted above

th e

tree.

This

carries

both a set o f b li nd rams, designed

to seal with or without a

wireline

in p la ce , and

a set of shear rams.

By altering

th e

position

of

a spool beneath th e rams, i t can be run

to

provide

wire line access

to

e it he r s tr in g .

The stack

is

used with

th e

dual 4 x 2 inch wireline riser and

is

operated

from a

se lf - co n ta i ne d se rv i ce control


3/10

system, designed to be moved with i t from one

rig

to

another.

During normal operations the tree and

down

hole

safety valves ar e

controlled

from the production

platform

through a

10 line

hydraulic umbilical.

For reasons

of

safety, however,

i t is desirable

during

a workover

to control

both

OP

stack

and tree from a

single control

panel

on the

workover

rig.

This

is achieved

by

routing the

incoming

10

line

tree

umbilical through a control

stab on the high pressure cap which seals off

the

top

of

the tree.

When the

cap is removed

to

permit t he

OP to

be run,

the circuit is

broken and a

stab

on the

OP stack

takes

the

place of

the one

on th e

cap.

The

stack functions

and tree valves ar e then controlled from a

single panel via twin 28 line

umbil ical s to

the

service control

unit on

the

workover rig.

THE SUBSEA M NIFOLD

The biggest

piece

of

subsea equipment

in

the

Field

is

the

underwater manifold which weighs

110

tonnes

See

Figure

5 . This assembly of valves and

connectors is

mounted on

the template directly

under the platform. The valves and pipework

ar e

mounted between

two

horizontal frames, th e upper

being supported 5 m above the lower

by

4

corner

posts

and a

central 30

inch column.

Passing vertically through the manifold

ar e

a

12

inch line to

carry the exported crude,

eight

4 inch production and

eight

2 inch lines

fo r

gas l i f t

11

female

riser connectors ar e

mounted

face up on

the

top frame

to

receive

the production

riser

and

projecting

below the lower frame ar e 17

stabs

and two connectors.

The

main centrally mounted

inch wellhead connector connects

on

to a

dummy

wellhead and

is the principal

means

of

securing the manifold to the

seabed.

The connector

is welded to the 30 inch column which runs

up

through the middle

of

the manifold and transmits

the

riser loads

imposed on

the

top frame down

to

the

foundation.

The second connector

is

mounted

on the 12

inch export

line.

A third horizontal frame

of

similar dimensions

and

known

as the manifold base, is mounted on the

30 inch

conductor below th e manifold i t sel f . Apart

from a

12

inch manually

operated

valve

in the

export line, there ar e no

other

valves on t he base;

i t

merely s erv es t o support the short spools

of

pipe

linking the

template

pipework

to

the female

receptacles which

receive the

manifold stabs.

By using this means i t was possible to insta l l

the manifold base

in

advance of the manifold and

to

make

up

and

install the

flanged pipework spools

between i t and

the

trees.

The

base

is

no t

designed to

be recovered

to the

surface. Components in the manifold can be

recovered fo r maintenance and in t he event of

major problems, the ent ire s tructure can be

lif ted into

th e moonpool

of

the

production platform.

As

in

the

case

of

the

trees,

this

would

require

diver intervention.

To understand

the

uses

of

the manifold i t should

be

considered in

the

l ight of the

19

separate risers

which

make up the riser

bundle see Table

1 .

By

opening

or c losing

valves

in the

manifold i t

provides the

means

to:-

a Shut in

the

flow subsea when

the risers

ar e

disconnected.

b Manifold th e

production or

gas

l i f t

flows

subsea

in the event that some of the risers

ar e not run.

c Cross connect the

service

risers

to the

crude carrying

risers to

allow flushing

with water

prior to

disconnect.

d Provide the

return

path fo r pigging the

flowlines

via the high pressure service

r iser .

e

Provide

a

link

between

the

high

pressure

r iser and the

flowlines

to create a f lowpath

fo r well

killing.

This

is

an

alternative

route

to

the normal means of

killing

a

well

through

the wireline riser.

t should be noted

that

the manifold contains

no

subsea chokes.

INSTALLATION ND HOOK UP

The manifold

base

was installed in June 1979. Prior

to

that

the

divers had jetted

out the

drill ing spoil

and installed pipe supports

on

th e template

fo r the

pipe spools which would run between the trees and

the

base. The operation was

conducted from a

semi

submersible

diving vesse l

anchored

over

the template.

Spools of pipe were fa:bricated on the deck

of

the rig

to

measurements taken. by

the

divers

using

special

j igs.

The

spools were then lowered

on

winches

over

the side to

th e seabed.

Hydraulic

bolt tensioners

were used fo r making

up

the f langed and clamped

connections

subsea. 25 m spool p ieces were laid

on the seabed at

the

edge of the template to act as

expansion

loops fo r the

incoming flowlines from th e

sate l l i te wells.

A combination of good weather and

careful

planning

by the contractors, SUb

Sea International, and th e

BP

construction

team

r esul te d i n

an exceptionally

successful

diving

operation.

This

included 22

spoolpieces

being

measured up,

fabricated, installed

and pressure tes ted in 45

days,

during which t ime

the average time in

the

water was 22 hours pe r day.

FLOWLINES

ND UMBILICALS

The second major construction job in the Field during

the 1979 summer was

the

laying and connecting

of

the

pipelines

and

the

umbilicals. Each of

the two

southern satell i te wellS had

to

be tied

in

back

to

the

manifold

by

twin 4

inch flowlines

and a

control

umbilical,

and

the 12 inch export line

had

to

be

laid to the loading buoy.

Originally

i t had been

intended

to

lay a ll the lines from the new Santa Fe

reel ship, Apache,

bu t

due

to

delays

in

he r

construction

programme, the

12

inch line

was laid

f irs t

from

the

semi-SUbmersible, Choctaw 2,

with the

Apache arriving la ter in the

Field

to la y the

flowlines

and

umbilicals.


4/10

The

4 inch

flowlines

were epoxy powder coated and

welded up

into 300m strings at

the

Santa Fe

base

at Leith.

Tests earlier

in the year had demonstrated

the ability

of the coating to

survive the

reeling

and unreeling process. th e

pipe

was welded up into

a

continuous

7 500 m

le ng th as

t

was

spooled

on

to

the 25 m diameter drum vertically mounted midships

on Apache.

During

the reeling process

a

supply boat was

installing dead

man

anchors

in

the

v ic in it y o f the

satelli te wells to prepare for the initiation

of

pipelaying. A submersible was

also

present during

the laying

operation

to assist in surveying the

l ine.

A pull- in technique developed by BP

was

used to

connect

the flowlines to the satel l i te trees.

After

the lines were laid, the ends of

the

flowlines

were held

off

the seabed

by

buoyancy

tanks

and

drag

chains

and were p Ul le d

in to

the lower trees

by

a

hydraulic

winch clamped

to

the

30

inch

conductor. Di ve rs t he n installed the short make-up

spool

to

complete the connection. At the template

end th e

pre-installed spoolpieces

served as

the

target

fo r the lay down operation and using

manipulator frames th e f langes

on

the spoolpieces

and pipeline were

brought

into

alignment. The

laying rate reached 440

m

pe r hour

including

the

ti me t ak en

to

t an anode

every

70

m The

best

total time

recorded

fOr initiating from the

dead

man anchor,

laying

1.7 kmof

flowline and

laying down·the

line at the template

recovering

and.adjusting

to length

required) was 14 hours.

The two control umbilicals were laid simultaneously

from reels on the stern of the Apache. Each

umbilical consists

of

ten inch

6

mm

hydraulic

hoses packed round a central 1s

inch 29

mm

steel

cable which provides

both strength

and weight.

Adequate tension was no t maintained, however during

the

abandonment of

the

two ends at the template and

entanglement

resulted.

This was picked by

the

submersible

s ur ve y and subsequently straightened

out by divers.

MANIFOLD

INSTALLATION

Only

the

manifold remained to be installed during

September. 1979 after Apache had

cleared the Field.

The

semi-submersible

rig Dundee Kingsnorth was

brought in

to

the shelter of Largo

Bay

in th e Firth

of Forth

where

the

flat

t op barge

carrying

the

manifold

was

manoeuvred between

her

twin

hulls.

Using the draw works and a string of dri l l pipe,

the

manifold was

l i fted up

into

the moonpool where

i t was secured during

the

tow

to the

Field.

After

a long wait

on

w ea th er a nd

delays

caused

by

last

minute equipment problems the

actual running of

the

manifold

was completed

in

6 hours. Extreme

care was

required

during

the

landing of

the

manifold

on

the base

to

avoid damage to the

stabs

and

connector s. A ll

went well except for the connector

on th e

export

line which would not c lo se and

has

sUbsequently had to be

replaced.

Although

in

theory

the repair could have been

carried

ou t by

recovering the

manifold

to

the

surface, in practice

subsea

replacement

of

components

is

very much

simpler

because

of

the

size

and w ei gh t

of th e

structure

which makes

handling

extremely

weather

dependent.

TH

PRODUCTION RISER

Like

the

Argyll

design, the Buchan production r iser

i s no t designed to stay connected in all

weathers,

but

must be recovered and stacked. in the derrick in

severe

conditions. I t

was

designed

to survive

12

m

maximum

waves with

the

associa

ted

rig

offset

and

current,

bu t recovery

of

the r iser will have to be

initiated at a considerably lower threshold.

Nevertheless i t is

the ability

of the

t anker to

stay

connected to

the

loading

buoy

rather

than

the

r iser

which

will

determine

the

production from

the Field.

The

r iser is shown

in

cross-section in Figure 6 and

in elevation in Figure 7. Prior to the introduction

of gas

l i f t the

bundle consi st s o f a central 12

inch

export r iser

surrounded

by ten

4

inch risers

one production r iser from each

of wel l s

and two

service risers

see Table 1).

The risers ar e

independent

of

each

other

and are run

and

tensioned

separately.

The

4

inch

r isers

are,

however constrained to deflect

with

the 12

inch

r iser by being spaced ou t from

t by

passing through

guide funnels. These ar e

supported

on arms mounted

every

7.6 m

along

t he l ength

of t he expor t

r iser .

Hence although each r iser

in the

bundle is independent

in the axial

direction, horizontally

the bundle tends

to

deflect

as

a single composite beam.

To reduce bending stresses at the b as e . of the r isers,

a universal joint is mounted in t he expor t r iser

directly

above the manifold. Fo r th e

same

reason,

the bottom 15 m joint

on

each production r iser is

made

from

extra

heavy

tubular.

With the introduction of gas l i f t

facilities

exist

to

cIampa 2 .inch gas

l i f t

r iser

to

each

production

riser

and

the

guide

funnels are

sized to accommodate

the

pair.

This r iser

concept

offers the advantage of operational

f lexibili ty. Only SUfficient risers need

to

be run

to

accommodate flow and required, individual

r isers can be p Ul le d and

replaced without

haVing to

recover the entire

bundle.

On

tpe other

hand r iser

handling time

during

the

running or

recovering

operation is increased

by

the need to

handle

individual lines sequentially.

The

r iser was th e

subject

of an immense amount

of

design analysis.

Model tests were conducted on the

bundle to establish drag and inertial coefficients

on

individual

r isers.

This

data

was

then

used

in

the

stress analysis

programme to

predict th e

bending

behaviour

of

individual

risers

as

well

as the gross

behaviour of the bundle. A

spectral

fatigue analysis

was conducted

to

determine fatigue l ife and

this

was

supported by

fatigue t es ti ng o f

a threaded

r iser

connector. In

addition,

during operation r iser

behaviour

will be continually monitored

by

instrumentation measuring parameters such

as

the

deflection

of the

universal join

and the pipe wal l

strain

at

two locations on

the r iser .

8


5/10

RIG MOUNTED

EQUIPMENT

As well

as

the

installation

of

production

equipment

the

rig conversion

programme incorporates several

modifications

in

t he r eg ion

of th e moonpool. These

include:-

enlargement of

the

moonpool

to

accommodate

both

production and wireline riser

provision of

four new

36

tonne

r iser tensioners

i n addition to the

eight existing 27 tonne units

installation

of

four

hose reels

to

carry the

main control umbilicals

see

below

modifications

to the

derrick

t o permi t handl ing

the

wireline

riser

through

a second

opening

in

the dril l deck floor

proVlslon

in

the

derrick fo r stacking

30

m

lengths

of

riser

provision of addi tional sheaves fo r tensioning

lines

and guide

wires. All

systems ar e

designed

to accommodate 5 m of

rig heave.

Flexible

rubber hoses ar e used to connect the

top

of the

risers

into

the moonpool pipework.

ONTROL SYSTEM

All the

subsea equipment is

controlled hydraul ical ly

via 4 hydraulic umbilicals deployed from the

production platforms.

Two

65 function umbilicals

ar e run to twin control pods mounted

on

the base

to

control

the

trees

and downhole

safety

valves

and two 62 function umbilicals

control

the

manifold

operation

through pods mounted

on

the

upper manifold

frame

see Figure

5 . Total duplication of

ll

key

subsea functions

is

provided between rig and control

pods.

A 10 line hydraulic umbilical

is

run to each tree

from the subsea tree pods.

inch

hydraulic lines

ar e used throughout.

The main umbilicals ar e deployed from 4 hose reels

situated

at

the edge of the moonpool. A guide line

system is used

to

run and recover the control pods.

9

In addition to the main control

panel

on the

r ig,

a

second smaller unit on the rill deck floor

provides

fo r

local control of the riser

connectors

on top of

the manifold.

This is

used

during running

and

recovering the production riser.

All

subsea valves ar e fail safe closed.

In

addition

the

subsea control system is ti ed in to the main rig

control panel

t o ensure

that in the

event of

a

shutdown subsea valves will be

closed.

CONCLUSIONS

The Buchan Field development can be

seen

as

the

natural successor

to

Argyll. While s im il ar i n

concept, i t

represents the extension

of

the

floating

production

principle to a field

with

more

subsea

completions,

bu t no radical departures in new

technology. In

terms of

field

size, however, i t

comes

close

to

the

l imit of

what can be

achieved

by

the

conversion

of a standard

dril l ing rig.

The next

step is

l ikely to

be custom

buil t f10ating production

platforms.

KNOWLEDGEMENTS

The author wishes

to

acknowledge BP

Trading Limited,

BP Petroleum Development

Limited

and

their

Partners

in the Buchan Development, namely St.

Joe Petroleum

Corporation, CanDel

Petroleum Limited,

Natomas

International, Gas and

Oil

Acreage

Limited,

Charterhall

Oil Limit ed, Loch ie l

Exploration UK

Limited, CCP

North Sea Associates and

City Petroleum

Corporation

fo r

permission to

produce

this

paper.

REFERENCES

1.

Darnborough

E. .

The Buchan

Field

Development . Europec Paper No.

230.

October, 1980.


6/10

TABLE

The

production r s r bundle

Risers

Number

Nominal

Operating Pressure

Size

Uns

psi

MFa

Produotion 8

4

5

34

Low

Pressure Servioe

4

5

1 5

High Pressure

Servioe

4

75

5

Gas Lift

8

2

325

Export

225

1 5


7/10

FUTURE

NORTHERN

S TELLITE

W

FLO TING

PRODUCTION

PL TFORM

SUBSE

TEMPL TE

WELLS

C LM

BUOY

SOUTHERN

S TELLITE

WELLS

Fig

Layout of the Buchan

Field

SPIDER SU RT-

PRODUCTION

RISERS

SUB SE

H R I S T M S ~ · ·

TREES

S T

W LL

FLOWLINES

SE BED

T E M P L T E ~

CONTROL

UMBILIC LS

UMBILIC LS

CENTR L EXPORT

RISER

M NIFOLD

Fig 2

Layout of

the template wel ls and

manifold


8/10

Fig

The template

PRODUCTION

STRING

NOM

UPPER

T I

I

LOWER

TREE

L PRODUCTION

PROPOSED

GAS

INJECTION

Fig

Schematic

of

a

subsea

tree


9/10

M NIFOLD

CONTROL

PODS

TREE

CONTROL

PODS

RISER

CONNECTORS

M NIFOLD

UPPER

FR ME

I I I E PORT

LINE

M NIFOLD

LOWER

FR ME

~ M N I F O L D

SE

Fig The subsea manifold

GUIDE

FUNN LS

~ E X P O R T

RIS R

S RVI

RISER

G S LIFT

RISER

PRODUCTION

RISER

Fig

6 Cross section of

th e production r is r


10/10

TENSIONERS

12 EXPORT RISER

4 RISERS 1

OFF

2

RISERS

OFF

GUI E

FUNNELS

UNIVERSAL

JOINT

MANIFOLD

TEMPLATE

Fig levation

of

the product ion r i s r

the design and installation of the buchan field subsea equipment

Documents