How to find field candidates for enhanced recovery by water additives on the NCS

Enhanced Recovery by water additivesFORCE Seminar 08. 02. 2007

Jan Bygdevoll, Principal Engineer, NPD

08.02.07 2

Why is a field a candidate for enhanced recovery ?Because there is more oil to potentially be recovered than by methods applied today

What is a method for enhanced recovery ?Anything that increase (or enhance) the recovery of oil (or gas) from a field

Injection methodsWater Gas, including CO2

Combination (WAG)Additives to injected water

SurfactantsPolymers Other ?

08.02.07 3

Norwegian Oil production RNB2006Oljeproduksjon, Norsk kontinentalsokkelAlle ressurskategorier

0

20

40

60

80

100

120

140

160

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200

1970 1980 1990 2000 2010 2020 2030

MSm

3

Uoppdagede ressurserRessurser i funnRessurser i feltReserverFaktisk

Produsert per 31.12.2005: 3,0 GSm3Gjenværende reserver: 1,2 GSm3Ressurser i felt: 0,4 GSm3Ressurser i funn: 0,1 GSm3Uoppdagede ressurser: 1,2 GSm3

M:\ La g\ D-Re ssAna lyse \ EKM\ Tot a lprod.xls

08.02.07 4

Oil production – prognosis to 2011 (RNB 2007)

0

50

100

150

200

1995 1997 1999 2001 2003 2005 2007 2009 2011

mill

ione

r Sm

³m

illion

Sm

3

0.0

1.0

2.0

3.0

mill

ione

r fat

per

dag

milli

on b

arre

ls p

er d

ay

Ressurser i funn/Resources in discoveries

Ressurser i felt/Resources in fields

Reserver/Reserves

Historisk produksjon/Actual production

08.02.07 5

Oil profiles for Norwegian fields

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1980 1985 1990 1995 2000 2005 2010 2015 2020 2025

MSm

3

Ekofisk

Statfjord

Gullfaks

Oseberg

Snorre

Troll

Heidrun

Grane

Draugen

NorneBalder

Valhall

Eldfisk

Ula

Grane

Rest

08.02.07 6

Status for NPD’s goal on Reserve Growth for Oil 2005 – 2015

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500

600

700

800

2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

Mill

Sm

3

G oal for reserve grow th

Prognosis autum n 2004 for reserve grow th total

Prognosis autum n 2004 for reserve grow th in existing fie lds

Cum ulative reserve grow th in total

Cum ulative reserve grow th from existing fie lds

08.02.07 7

Status for NPD’s goal on Reserve Growth for Oil 2005 – 2015

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100

200

300

400

500

600

700

800

2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

Mill

Sm

3

G oal for reserve grow thPrognosis autum n 2004 for reserve grow th totalPrognosis autum n 2004 for reserve grow th in existing fie ldsCum ulative reserve grow th in totalCum ulative reserve grow th from existing fie ldsRNB 2006 O perators prognosisRNB 2007 O perators prognosis

08.02.07 8

Produced, yet to produce and oil remaining in ground based on current plans

-600

-400

-200

0

200

400

600Ek

ofis

k

Trol

l II

Eldf

isk

Valh

all

Snor

re

Hei

drun

Stat

fjord

Ose

berg

Gul

lfaks

Trol

l I

Ose

berg

Sør To

r

Gul

lfaks

Sør

Njo

rd

Gra

ne

Vest

Eko

fisk

Bra

ge

Bal

der

Kris

tin Ula

Dra

ugen

Snøh

vit

Ose

berg

Øst

Nor

ne

Visu

nd

Vesl

efrik

k

Vigd

is

Alv

heim

Gyd

a

Tord

is

Åsg

ard

HodM

Sm³

Remaining oil in ground at planned cessationProduced oil end 2006Remaining oil reserves

08.02.07 9

Produced, yet to produce and oil remaining in ground based on current plans

-600

-400

-200

0

200

400

600

MSm

³

Remaining oil in ground at planned cessationProduced oil end 2006Remaining oil reserves

Chalk reservoir

Sand reservoir w/ water inj

Sand reservoir w/ gas inj

08.02.07 10

Produced, yet to produce and oil remaining in ground based on current plans

-100

-80

-60

-40

-20

0

20

40

60

80

100

120Sn

øhvi

t

Ose

berg

Øst

Nor

ne

Visu

nd

Vesl

efrik

k

Vigd

is

Alv

heim

Gyd

a

Tord

is

Åsg

ard

Hod

Fram

Stat

fjord

Nor

d

Embl

a

Frøy

Alb

uskj

ell

Stat

fjord

Øst

Kvi

tebj

ørn

Varg

Yme

Tyrih

ans

Jotu

n

Glit

ne

Tam

bar

Mim

e

Urd

Volv

e

MSm

³

Remaining oil in ground at planned cessationProduced oil end 2006Remaining oil reserves

08.02.07 11

Development in recovery factor grouped by field seize

20

30

40

50

60

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006

Rec

over

y Fa

ctor

Oil

(%)

<15 million Sm3 oil > 50 million Sm3 oil15 - 50 million Sm3 oil Average all fields

NB! The number of fields varies with time

08.02.07 12

Recovery factor versus Reservoir Complexity Index (RCI) – a tool for estimating potential ?

y = -0.776x + 0.7779R2 = 0.8095

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 RCI

Utv

gra

d

08.02.07 13

Reservoir Complexity Index (RCI)– parameters used in evaluation

Thin oil zone and production severely restricted by gas or water coning

problems

Some coning problems from gas

cap or aquifer

No coning tendency.

Describes the coning problems associated with a gas cap or aquifer support. Large complexity only in cases where the oil band is thin.

Coning tendency

< 0.50.5 - 11 - 22 - 4.5>4.5

Describes the areal concentration of STOOIP and is defined as STOOIP/area (mill. Sm3/km2)

STOOIP density

Highly discontinuous. Difficult to

predict/describe injector/producer

connecting flow units.

High degree of continuity

Describes the stratigraphic continuity of the flow units in the main flow direction within the defined reservoir

Lateral stratigraphiccontinuity

The fault properties restrict fluid flow significantly. (High density of faults with throw larger than

reservoir thickness and/or 'zero'

transmissibility).

The fault properties does not restrict

fluid flow.

Describes how fluid flow between wells is affected by fault density, fault throw, fault transmissibility, ….

Structural complexity

>43-42-31-2<1

Describes the permeability contrast between geological layers/faciestypes, and is calculated as log10[Kmax/Kmin]

Permeability contrast

< 1010-100100-1000

1000-10000

> 10.000

Describes the pore volume weighted average permeability in the main flow direction of the defined reservoir. mD

Average permeability

54321

High complexityLow complexity

Complexity score

DescriptionComplexity attribute

08.02.07 14

Important issues in estimating potential for different methods to increase recovery

How is the remaining oil distributed in the reservoir?

Temperature

Fluid chemistry

Mineralogy

Topside facilities and wells

Cost, both investment and operational

Remaining field life

Other issues

08.02.07 15

Reservoir temperature in fields on NCSFrigg

Snøhvit

Odin

TrollA

lvheimA

lvheimB

alderA

lvheimD

raugenG

ullfaksG

ullfaksG

ullfaksH

eimdal

Grane

Balder

Gullfaks

Glitne

TordisTordisS

nøhvitJotun

TordisH

eidrunS

kirneS

tatfjordV

alhallS

tatfjord Øst

Snorre

TordisU

rdS

nøhvitS

leipner Øst

Gullfaks S

ørS

tatfjordH

odS

norreS

tatfjord Nord

Orm

en LangeM

ikkelB

rageS

tatfjordS

ygnaS

tatfjord Nord

Norne

Gullfaks S

ørS

igynS

igynH

odFrøyG

ullfaks Sør

Visund

Njord

Njord

Gullfaks S

ørS

leipner Vest

Gullfaks S

ørLille-FriggV

aleV

argG

ullfaks Sør

Cod

Vest E

kofiskE

kofiskE

ddaA

lbuskjellU

laH

uldraK

vitebjørnK

ristinTam

barE

mbla

Mim

eK

ristin

0

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180

Fields

Deg

. C

08.02.07 16

Methods to improve injection ?

To obtain better sweepand produce by-passed oil ?

To reduce the residual oil saturation in

the swept sone?

Economical issues

Environmental issues

08.02.07 17

Oil cost curve, including technological progress:availability of oil resources as a function of price

08.02.07 18

Cost and potential of Surfactant compared with other methods to increase recovery

08.02.07 19

Potential for surfactant flooding ?

In 1991 a work group in Statoil, Hydro a Saga and NPD estimated a technical potential from 80 to 130 MSm³

Based on an Sorw > 0.25 and immediate startup in 10 reservoirs

”Profitable reserves (potential)” was estimated to 55 to 87 MSm³ including the condition of Seff > 40 Sm³ oil/ton surfactant

Journal of Petroleum Science & Engineering, April 1992

What have16 years done to the potential?Is it time for a new potential study?