DIACS (SCRAMS) completion at DIACS (SCRAMS) completion at Gullfaks CGullfaks C

C-29 a 2 year story

The Gullfaks fieldThe Gullfaks field

Reserves 321 mill SmReserves 321 mill Sm33 oiloil

Produced 277 mill SmProduced 277 mill Sm33 oil oil (02.2001)(02.2001)

Daily production GFC Daily production GFC approximately 13000 Smapproximately 13000 Sm33 (02.2001)(02.2001)

o

C

B-1

2 15'

2800

2700

2500

2600

2700

2400

2800

2700

2600

2700

2650

2400

2300

2200

2900

2500 24

00

2300

2400

2600

2500

2300

2300

2400

2400

2500

2400

2000

2500

2500

2600 2500 2500

2400

2300

2400

21002300

2000

1900

200021

00

2100

2000

2100

2500

14

11

C-2¦

C-8C-7

C-6

C-13

C-4X C-4

C-1

7(F)

13

C-14

A-36(2)

C-12(F)

9C-3

12

A-25A

A

5

A-11

3

B

A-3H(F)

A-5HA-3AH(F)1

A-4H

B-10A

4

C-5

C-17

B-10

B-25

19

A-36

A-41

o61 15'

o61 10'

o 2 15'o 2 10'

o61 10'

o61 15'

o 2 10'

DOMINO SYSTEM

ACCOMODATION ZONE

HORST COMPLEX

4000

3000

5000

0000

1000

2000

4000

3000

5000

0000

1000

2000

1200 14001000800600CDP 400

Statfjord Fm.

Brent Group

Base Cretaceous unconformity

Cretaceous/Tertiary sediments

W E

ACCOMODATION

HORST COMPLEX

Geological setting

DOMINO SYSTEM

Intra-Lomvireflector

SSurfaceurfaceCControlledontrolledRReservoireservoirAAnalysis andnalysis andMMonitoringonitoringSSystemystem

WHAT IS SCRAMS ?WHAT IS SCRAMS ?A SYSTEM FOR DOWNHOLE ZONAL PRODUCTION

CONTROL AND PRESSURE MONITORING

HYDRAULIC LINES FOR SLEEVE OPERATIONELECTRIC LINES FOR SLEEVE OPERATION AND PRESSURE MONITORING

ZONAL ISOLATION PACKERS

ICV "CHOKES" (INTERVAL CONTROL VALVES)PRESSURE SENSORS ANNULUS AND TUBING

TOP STATFJORD MAPTOP STATFJORD MAP

1900

2000

K3

L1

L2

C-29

C-39

(95/99)

(2000)

500m

L2

CROSS SECTION ALONG C-29CROSS SECTION ALONG C-29

"LOWER" STATFJORD

"UPPER" LUNDE

C-29

"UPPER" LUNDE

L2

10-2

0 m

FA

ULT

L1

"LOWER" LUNDE

"UPPER" STATFJORD

70 m

FA

ULT

K3

BASECRETACEOUS

MOD.-GOOD CONTINUITYHIGH PERMEABILITY

MOD. CONTINUITYHIGH PERMEABILITY

MOD. CONTINUITYMOD. - HIGH PERM.

LOW CONT.LOW PERM.

PRODUCTION SCENARIOSPRODUCTION SCENARIOS

No downhole production control in C-29

Sequential production of the reservoir zones in C-29

Drill a new well C-39 to accelerate Statfjordproduction

Downhole production control in C-29

Simultaneous production of all reservoirzones in C-29

Drill a new well based on production experiencein C-29 for optimalization

1900

2000

K3

L1

L2

C-29

C-39

K3

C-39

(original proposedposition)

(2000)

WHAT DOTHE ICVCHOKES

LOOK LIKE ?

.....WELL.....

2/3 OPEN2/3 OPEN 1/3 OPEN1/3 OPEN

WELL INTERVENTIONS CRITICAL FACTORSWELL INTERVENTIONS CRITICAL FACTORS

XMT

UPPER STATFJORD

LOWER LUNDE

UPPER LUNDE

LOWER STATFJORD

The recompletion with drilling rig, including running the Scrams assembly, went according to plan

Increased cost experienceddue to:

1. Pressure control i Statfjord2. Killing of perforation. Fracturation

pressures and kill fluid3. Clearance between Scrams

assembly and liner

Measure diff. pressure acrossdownhole choke vs rate

0 100 200 300 400 500 600 700 800 9000

RATE [Sm3/D]

0

5

10

15

20

25

DIF

FE

RE

NT

IAL

PR

ES

SU

RE

[b

ar]

1/3

3/3

2/3

WELL ON PRODUCTION - PERIODIC TEST NEEDEDWELL ON PRODUCTION - PERIODIC TEST NEEDED1. Multi-rate test2. Establish max. sand free rateFOR EACH ZONE:

0 100 200 300 400 500 600 700 800 9000

RATE [Sm3/D]

230

240

250

260

270

280

290

300

TU

BIN

G P

RE

SS

UR

E

Establish IPRfor each choke setting

1/3

2/3

3/3

-lower Lunde: Mainly water production, possibly due to fracturing and losses during kill operations

OPTIMIZING CHOKE SETTINGSOPTIMIZING CHOKE SETTINGS

0 100 200 300 400 500 600 700 800 900

RATE (Sm3/D)

240

250

260

270

280

290

300

310

320T

UB

ING

PR

ES

SU

RE

(b

ar)

RE

F. L

OW

ER

ST

AT

FJO

RD

UPPER STATFJ 3/3UPPER STATFJ 2/3UPPER STATFJ 1/3LOWER STATFJ 3/3LOWER STATFJ 2/3LOWER STATFJ 1/3UPPER LUNDE 3/3UPPER LUNDE 2/3UPPER LUNDE 1/3LOWER LUNDE 3/3

OPERATINGTUB. PRESS.

EXAMPLE FROM INITIAL CONDITIONS

OPTIMIZED DRAINAGE STRATEGYOPTIMIZED DRAINAGE STRATEGY

C-29

ca 650 m

"LOWER" STATFJORD

BCU

"UPPER" LUNDE

"UPPER" STATFJORD

REVISED C-39

"LOWER" LUNDE

L1 L2

1750

2000

2250

PROPOSEDC-39

NS

As a consequence of installing Scrams, the drilling of a new well, C-39, was postponed until gaining production experienceA revised C-39 is on stream further south (producer and injector)

TEST

TEST

PRESSURES

OIL

RATES apr-99

mai-99jun-99

jul-99aug-99

sep-99okt-99

nov-99des-99

jan-00feb-00

mar-00apr-00

mai-00jun-00

jul-00aug-00

sep-00okt-00

nov-00des-00

jan-01feb-01

0

100

200

300

400

500

600

700

800

900

1000

OIL

RA

TE

[S

m3/

D]

UPPERSTATFJLOWERSTATFJUPPERLUNDELOWERLUNDE

feb-99 mai-99 aug-99 des-99 mar-00 jun-00 okt-00 jan-01 apr-01

Date

250

260

270

280

290

300

310

320

Res

ervo

ir pr

essu

re, b

arLOWER LUNDEUPPER LUNDELOWER STATFJUPPER STATFJ

Ref./1850 m TVD MSL

ECONOMYECONOMY

The value is related to the total development of the areaComparison of 2 cases (from start of Scrams operation):

Case 1: C-29 without Scrams and C-39 in original locationCase 2: C-29 with Scrams and C-39 in revised location further south

How do we evaluate the economic value of Scrams in C-29?

DIFFERENCE IN NET PRESENT VALUEBEFORE TAX, INCLUDINGINVESTMENTS:

apr-1999apr-2001

apr-2003apr-2005

apr-2007apr-2009

apr-2011apr-2013

apr-2015apr-2017

0

500

1000

1500

OIL

RA

TE

Sm

3/d

Scrams in C-29Revised 39

No scrams in C-29C-39 as originally

proposed 100 mill NOK

In favour of the casewith SCRAMS

Production flexibility and optimizationPressure monitoringZonal rate allocationZonal testingAccelerated production and increased recoveryReservoir strategy was optimized based on production experienceExperience from production with downhole flow control

+ -High costs due to complex operations prior to Scrams installation (not Scrams related)Effect of choking of the ICV's in "upper" and "lower" Statfjord is less than required for simultaneous production of all zones Continuous pressure monitoring currently not possible due to technical solutionIncreased water cut from "lower" Lunde (related to kill operation)

SCRAMS IN C-29 - CONCLUSIONSSCRAMS IN C-29 - CONCLUSIONS