statoil experience on meor for norne...2014/11/18 · economic lifetime 2016 45% 60 % 56% increased...
TRANSCRIPT
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
Force workshop 18/11 2014 - MEOR: From theory to field 4
Norne initial (1997) and performed Drainage Strategy
1997 1998 2003 2006 2018
Tofte
Fm.
Garn
Fm.
L.Ile
Fm.
U.Ile
Fm.
Force workshop 18/11 2014 - MEOR: From theory to field 5
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
Force workshop 18/11 2014 - MEOR: From theory to field
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
Force workshop 18/11 2014 - MEOR: From theory to field 8
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
Force workshop 18/11 2014 - MEOR: From theory to field 9
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
Force workshop 18/11 2014 - MEOR: From theory to field
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
Force workshop 18/11 2014 - MEOR: From theory to field 11
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:
Force workshop 18/11 2014 - MEOR: From theory to field 12
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
Force workshop 18/11 2014 - MEOR: From theory to field 15
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 and cumulative production
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 and cumulative production
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
Force workshop 18/11 2014 - MEOR: From theory to field 16
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
Cumulative liquid production (% of total)
Water cut versus liquid produced
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
Cumulative liquid production (% of total)
Water cut versus liquid produced
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
Cumulative liquid production (% of total)
Water cut versus liquid produced
(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
Force workshop 18/11 2014 - MEOR: From theory to field 17
• 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
Force workshop 18/11 2014 - MEOR: From theory to field 18
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
Force workshop 18/11 2014 - MEOR: From theory to field 19
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)
Force workshop 18/11 2014 - MEOR: From theory to field 20