Statoil experience on MEOR for Norne...2014/11/18 · Economic Lifetime 2016 45% 60 % 56% Increased...

Force workshop – MEOR: From theory to field David Grabowski and Trygve Maldal

18 Nov 2014

Statoil experience on MEOR

for Norne

Agenda

• Norne

− Concept

− Initial drainage strategy

− Performed drainage strategy

• Microbes for EOR

− Microbial growth

− MEOR mechanism

• Production data analysis

• Conclusion and way forward

2 Force workshop 18/11 2014 - MEOR: From theory to field

Norne FPSO concept: Common sea water solution: - Subsea development:

Optional N/P

Chloritt

Biocid

Defoamer

Vacum pumps

O2 scavanger

De aerotor

N/P added

Corrosion resistant

- Raw seawater:

Force workshop 18/11 2014 - MEOR: From theory to field 3

Norne raw seawater solution is copied at Tyrihans and a

Brasil offshore field named Albacora, OTC4167

NORNE 2006

Not 3 Upper Not Shale

Not 2

(Not

sandstone)

Not 2.3

Not 2.2

Not 2.1

Not 1 Lower Not Shale

Ile 2

Ile 2.2

Ile 2.1

Ile 1

Ile 1.3

Ile 1.2

Ile 1.1

Tofte 2 Tofte 2.2

Tofte 2.1

Tofte 1 Tofte 1.2

Tofte 1.1

Tilje 4

Tilje 3

Norne Reservoir

• Generally good reservoir quality:

Porosity 24 - 28%

Permeability 100–10000 mD

• Reservoir thickness ~ 230 m

Gas cap ~75 m

Oil leg ~110 m (light oil)

• Laterally homogenous reservoir

• Faults and carbonate cemented

zones have a significant influence

on the flow pattern

• Barrier modelling is important:

− Carbonate cemented layers

− Faults

D

C

E I H

G

KILOMETERS

0 1 2

KILOMETERS

0 1 2


Norne initial (1997) and performed Drainage Strategy

1997 1998 2003 2006 2018

Tofte

Fm.

Garn

Fm.

L.Ile

Fm.

U.Ile

Fm.


6

Drainage strategy

Pressure support mainly based on raw seawater injection (no oxygen removal)

Produced water is treated and dumped into the sea

(A)MEOR ((Aerobic) Microbial Enhanced Oil Recovery) optimized after production

start-up by injection of nitrate, phosphate and oxygen to improve the MEOR

efficiency (start-up Feb 2001)

Force workshop 18/11 2014 - MEOR: From theory to field

Microbial growth:

7

Carbon

Nitrogen

Phosphorous

Respiration

CO2

Organic

carbon

O2 H 2O

NO3 N 2

SO4 H 2S E

lectr

on a

ccepto

r:

Aerobic resp.

Anaerobic resp.

Anaerobic resp.

Energ

y e

ffic

iency:

1

~ 3

~

10


Microbial growth:

To get growth of bacteria, there are three key

constituents required:

• The bacteria must have "food". “Food " means

in practice that they need a carbon source and

some phosphorus and nitrogen.

• The bacteria must have "energy ". Energy

means that they must have an electron

acceptor. This may be oxygen (O2), nitrate

(NO3 -) or sulfate (SO4

2 -).

• The bacteria must have an adequate

environment to live in (near well area which

has been made non toxic during injection of

sea water).

Positive other effect: Nitrate dosing at lab and

field experiences show that this is an effective

way to significantly delay/mitigate for an

expected unwanted H2S souring


MEOR mechanism:

• sufficient generation of biomass for

dynamic plugging

• heterogeneous reservoirs

− layered reservoir with no

communication:

• only local plugging required

− communication between layers:

• plugging at some distance

away from the injector

1. Reduction of Sorw 2. Diversion – red. perm. in high perm zones

0,001

0,01

0,1

1

10

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Run time (days)

IFT

(m

N/m

)

OW IFT

OWB IFT

4.0 ml/h

0.9 ml/h

1.8 ml/h

2.7 ml/h

5.4 ml/h

Interfacial tension versus run time measured by laser light scattering.

The stimulated bacteria are growing by continuous supply of nutrients.

Challenge:

How can local stimulation gives global response?

Can Strand theory, SPE 154138, be valid?

Ref.: Stanley Jones experiments: SPE 12125


10

Norne Reserves Development PDO 1994 2009

0

10

20

30

40

50

60

70

80

90

100

1994 1998 2001 2003 2005 2007 2008 2009C

um

Oil

, M

Sm

3

Prod history

Better lateral

communication

More horizontal wells

Upgrade oil cap

G-segment

Economic Lifetime 2016

45%

60

%

56%

Increased

WI capacity MEOR

K-

template

Ext

Lifetime

2021 M-

template

JPT – April 1996 (296-339)

2013: Produced 56% (88 MSm3)

of STOOIP


Production data analysis

Objectives:

1. How can production performance indicate any MEOR effect?

2. Evaluate production performance in light of quantitative and qualitative seawater

fraction during production

− during plateau phase

− during decline

3. Evaluate seawater fraction after sea water breakthrough

Challenges: production allocation, operational issues, seawater fraction measurement

(frequency, regularity, reliability), lack of baseline, very few wells with low (no) seawater

production


Illustration of assumed production performance:

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 %

10 %

20 %

30 %

40 %

50 %

60 %

70 %

80 %

90 %

100 %

0 % 10 % 20 % 30 % 40 % 50 % 60 % 70 % 80 % 90 % 100 %

Cu

m o

il (

% o

f to

tal)

Oil

ra

te [

% o

f p

ea

k]

Cum liquid production (% of total)

Oil rate and cumulativ production

Rate Seawater Cum Seawater Cum aquifer Rate aquifer

0 %

10 %

20 %

30 %

40 %

50 %

60 %

70 %

80 %

90 %

100 %

0 % 10 % 20 % 30 % 40 % 50 % 60 % 70 % 80 % 90 % 100 %

Wate

r cu

t

Cum liquid production (% of total)

Water cut versus liquid produced

Water cut - Seawater

Water cut - Formationwater

Expected similar:

• Oil rate

If higher recovery /

favourable prod.

performance:

• Later water

breakthrough

• More gradually

increase in water cut

• Shorter oil rate tail

• Lower volume of

water produced

compare to volume of

oil produced

…if to example injected SW with MEOR give higher recovery than FW/PWRI:


NB: From Dake: «the practice of reservoir engineering…»

NB:

The water cut

development is always a

function of the reservoir

geometry and reservoir

characteristics……

Force workshop 18/11 2014 -

MEOR: From theory to field 13

14

7327167

7325167

7323167

7321167

7319167

463313 461313 459313 457313 455313

7319167

7321167

7323167

7325167

7327167

KILOMETERS

0 1 2

2 3

1

455313 457313 459313 461313 463313

Sisik

Trost

Stær

Norne, Wells pattern

Segment G

Segment C

Segment D

Segment E

1

2

3

Production performance, 3 ILE producers

• High productivity and high cumulative production

• With seawater support, the wells are producing more before

water breakthrough


0

2

4

6

8

10

12

0

1000

2000

3000

4000

5000

6000

7000

8000

0 1000 2000 3000 4000 5000 6000

Cu

m o

il [M

Sm3]

Oil

rate

Sm

3/d

]

Days after start up

Well 2 oil rate and cumulative production

Well 2 oil rate

Cum oil

0

10

20

30

40

50

60

70

80

90

100

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 1000 2000 3000 4000 5000 6000

Inje

ctio

n w

ate

r fr

acti

on

Wat

er

cut

Days after start up

Well 2 water cut and seawater fraction

Well 2 water cut

Seawater fraction

Base Ile

0

2

4

6

8

10

12

0

1000

2000

3000

4000

5000

6000

7000

8000

0 1000 2000 3000 4000 5000 6000

Cu

m o

il [M

Sm3]

Oil

rate

Sm

3/d

]

Days after start up


Well 3 oil rate

Cum oil

0

10

20

30

40

50

60

70

80

90

100

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 1000 2000 3000 4000 5000 6000

Inje

ctio

n w

ate

r fr

acti

on

Wat

er

cut

Days after start up

Well 3 water cut and seawater fraction

Well 3 water cut

Seawater fraction

Ile

0

2

4

6

8

10

12

0

1000

2000

3000

4000

5000

6000

7000

8000

0 1000 2000 3000 4000 5000 6000

Cu

m o

il [M

Sm3]

Oil

rate

Sm

3/d

]

Days after start up


Well 1 oil rate

Cum oil

0

10

20

30

40

50

60

70

80

90

100

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 1000 2000 3000 4000 5000 6000

Inje

ctio

n w

ate

r fr

acti

on

Wat

er

cut

Days after start up

Well1 water cut and seawater fraction

Well 1 water cut

Seawater fraction

Ile Not2 + Ile

Water cut development and cumulative production for well 1, 2 and 3 on Norne

Well Cumulative oil production % oil of total produced

after water breakthrough

Produced water /

produced oil

MSm 3 Bbl. water / bbl. oil

1 9,65 38 0,95

2 11,53 15 0,25

3 7,08 24 0,34


0

10

20

30

40

50

60

70

80

90

100

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1,0

0 10 20 30 40 50 60 70 80 90 100

Cu

m. o

il (%

of

tota

lt)

Wat

er

cut

Cumulative liquid production (% of total)

Well 1 Well 2 Well 3 Well 1 Cum oil Well 2 Cum oil Well 3 Cum oil

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 10 20 30 40 50 60 70 80 90 100

Wat

er

cut



0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 10 20 30 40 50 60 70 80 90 100

Wat

er

cut



0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 10 20 30 40 50 60 70 80 90 100

Wat

er

cut



(A)MEOR in water leg – Norne well 1

Prod.: 9,7 MSm3 - 0,95 bbl water/bbl oil

Ex of Aquifer water drive –

Prod.: 4,8 bbl water/bbl oil

(A)MEOR in oil leg – Norne wells 2 and 3

Prod.: well 3: 7,1 MSm3 and 0,36 bbl water/bbl oil

well 2: 11,5 MSm3 and 0,24 bbl water/bbl oil


• 30 % of STOOIP is produced at water breakthrough (defined at 0.10 water cut)

• After 15 years of production, recovery is 56 % and it has been lifted on average 0.43 bbl. water /

1.00 bbl. of oil at this time!

• Water cuts gradient of the field has a nearly linear development.

• The wells in the study are typical Norne wells with high productivity and high cumulative production

(7-11 MSm3 )

• Well 1 produce a lot more oil after water breakthrough compare to well 2 and 3. Sea water

production shows that well 1 has less contact with injector well compare to well 2 and 3. This prod.

performance can indicate higher residual oil saturation / less sweep efficiency compare to segment

B/D with wells 2 and 3. This condition can partly be caused by MEOR??

Production performance on Norne, some results


Conclusions and way forward • Norne wells production is in general quite good and led to very high Recovery Factor

Good reservoir properties, few barriers to flow

Good reservoir management, use of 4D seismic, etc

MEOR?

Indication that raw seawater injection helps to improve the well production efficiency with a

higher production on plateau and relatively small volume of oil produced after water

breakthrough.

• Not able (yet) to quantify the contribution of MEOR based on production data and simulation.

However, the production performance is as expected if MEOR works as prognoses, the

production performance indicate low remaining oil saturation in the zones penetrated by

injection water

• Learnings: lack of base line survey, more regular/reliability of seawater sampling, production

allocation must be improved

• Way forward: use of tracers data, field analogues re-injecting produced water, saturation logs

( uncertainty in Sorw?), analyze H2S production data


Acknowledge:

Statoil, Norne and license partners, ENI and Petoro: give data

and approved the presentation

Egil Sunde – Founder and initiator of MEOR activities in Statoil

Janiche Beeder – Microbial growth mechanisms

Synøve Tevik – History Norne, data input (slide 10)


Statoil experience on MEOR for Norne...2014/11/18 · Economic Lifetime 2016 45% 60 % 56% Increased...

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Transcript of Statoil experience on MEOR for Norne...2014/11/18 · Economic Lifetime 2016 45% 60 % 56% Increased...