meor: from an experiment to a model sidsel marie nielsen, amalia halim, igor nesterov, anna eliasson...
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MEOR: From an Experiment to a Model
Sidsel Marie Nielsen, Amalia Halim, Igor Nesterov, Anna Eliasson Lantz, Alexander Shapiro
Stavanger, 18 Nov 2014
RECOVERY MECHANISMS
Reduction of oil-water interfacial tension (IFT) by surfactant production and bacteria.
Fluid diversion by microbial plugging.
Reduction of oil viscosity.
Gas production.
2
3
EXPERIMENTS
4
CHALK ROCKNorth Sea Reservoirs are mainly chalk reservoirs
Chalk rock: Small pore throats, comparable to microbe sizes
Stevns Klint outcrop: Model study, pore throat size: 0.004-6.1µm
Bacterial sizes: 0.5x3µm
Scanning Electron Microscope of Cretaceous, Maastrictian M1b1 unit reservoir chalk (Maersk Oil, 2014)
SPORE PROPERTIESModel bacteria used in penetration test:Bacillus licheniformis 421 (spore-forming)Pseudomonas putida K12
Vegetative cellGrowing with metabolism.
SporeSporulation induced by stress.Dormant (non-growing).Smaller size.Different surface properties.Reactivation.
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http://bio1151.nicerweb.com/Locked/media/ch27/endospore.html
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Schematic Core Flooding Set-upInjection cylinder 1 = brine/nutrient 2 = bacteria3 = crude oil
Pressure tapped core holder
Fridge
P1 P2 P3
Fraction collector
dPi = differential pressure transducer = pressure tapped (0.5”, 1.5”, 2.5”) = thermocouple = valves = safety valves
Temperature controller
ISCO pump(injection)
dPi
ISCO pump(Sleeve pressure)
Heating jacket
1 2 3
Webcam
Methods
7
Spore-forming vs non-spore-formingBacteria penetration study/One phase liquid core flooding: Halim et. al., Transp. Porous Med. (2014) 101, 1–15. doi:10.1007/s11242-013-0227-x
• More cells were found in the effluents of core flooding with B. licheniformis 421 as compared to P. putida K12
• Survival/motion of bacteria can be mainly due to spores.
In 2 3 4 5 6 71E+00
1E+02
1E+04
1E+06
1E+08
1E+10
0123456789
bacteria cell (core 2)bacteria cell (core 10)
PVI
viab
le c
ell (
cfu/
mL)
B. licheniformis 421
In 2 3 4 5 6 7 1 2 3 4 5 6 71E+00
1E+02
1E+04
1E+06
1E+08
1E+10
0123456789
bacteria cell (core 5)bacteria cell (core 9)
PVI
viab
le c
ell (
cfu/
mL)
pH
P. putida K12
8
Penetrated bacteriaBacteria penetration study/One phase liquid core flooding: Halim et. al., Transp. Porous Med. (2014) 101, 1–15. doi:10.1007/s11242-013-0227-x
B. licheniformis 421 cells under DAPI staining (a) in growth media, before injection into a chalk core plug, cell size 0.5 x 3µm (b) in the effluent from a chalk core plug, spore formation
spore
ba
9
Flooding sequences
1. Injection of SS (2-3 PVI)2. Injection of crude oil until Swi
3. Injection of 1PV SS (1st SS)4. Injection of bacteria (1PV)5. Incubation (3 days)6. Injection of SS until Sor (2nd SS)7. Injection of nutrient (1PV)8. Incubation (7 days)9. Injection of SS (3rd SS)
Secondary
1. Injection of SS (2-3 PVI)2. Injection of crude oil until Swi
3. Injection of SS until Sor (1st SS)4. Injection of bacteria (1-3PV)5. Incubation (3 days)6. Injection of SS (2nd SS)
Tertiary
“Tertiary recovery” “Secondary recovery”
10
Core plug properties
Core ID
k before (mD)
k after (mD)
before
(%)
after (%)
26_water 3.2 2.8 30.8 30.726_3rd m 3.2 3.1 31.1 30.7
26_2nd m 3.1 3.2 30.7 30.8
• Core 26 – homogenous reservoir chalk core
• No significant change in k and before and after experiment
• No fractures based on CT scan results before and after experiments
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Results
Tertiary oil recovery method with production stopped at 11.5 PVI.1 PV bacteria injected and incubated.Additional oil: 2.3 % OOIP.
Core no Sor (% OOIP)
26_water 45.226_3rd method 44.2
Samples Viscosity (cP)
Crude oil 4.96SS 0.55
SS+molasses+bacteria 0.55
0 2 4 6 8 10 12 14 16 18 20 220
20
40
60
80
100
core 26_water_1st SScore 26_water_2nd SScore 26_3rd method_1st SScore 26_3rd method_bacteriacore 26_3rd method_2nd SS
PVI
cum
mul
ative
oil
prod
uctio
n (%
OO
IP)
1.4 %55.8% 0.9 %
Do bacteria produce more oil?
12
Results
Secondary oil recovery method produces 3.3 % OOIP compared to tertiary method. 1 PV bacteria injected 1 PV after break-through.
Core no Sor-1PV (%)26_2nd
method 56.7
0 2 4 6 8 10 12 14 16 18 20 220
20
40
60
80
100
core 26_water_1st SScore 26_water_2nd SScore 26_3rd method_1st SScore 26_3rd method_bacteriacore 26_3rd method_2nd SScore 26_2nd method_1st SScore 26_2nd method_bacteriacore 26_2nd method_2nd SScore 26_2nd method_nutrientcore 26_2nd method_3rd SS
PVI
cum
mul
ative
oil
prod
uctio
n (%
OO
IP)
vs. 2nd method 3.3 % (at 18.3 PVI)
Secondary vs tertiary recovery?
Total oil recoveryWater : 54.8%Bacteria_3rd : 58.1%Bacteria_2nd : 61.6%
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SIMULATIONS
1D MEOR SIMULATOR Generic model. Growth and other reactions. Bacterial surfactant reducing IFT. Bacteria attachment due to
filtration or equilibrium adsorption.
Plugging Application of spore-
forming bacteria.
SIMULATOR OVERVIEW
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www.123rf.com
1D MEOR MODEL
1 1
p pn n
ij j j ij j j ij j
s v f qt x
{ , , , , }, { , }i o w b s m j o w
15
ReactionBacteria, surfactant and substrate.
Sporulation
AttachmentIrreversible deep bed filtration.
Pore size vs. bacteria size.
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( )·
( )s w
b sb bw maxs s w
r Y rK
0att bwr v
00.1sp
spa spwttr v
( )s x xyij bsr K a
bacteria pore substrateb sp sa s aa
SOURCE TERMS
SPORULATION
17
Sporulation Sigmoid-shaped curve
for stress response in bio-systems
Conversion releases substrate.
Reactivation Triggered by good
conditions for survival10-7 10-6 10-5 10-3 10-2 10-1
0.0
0.1
0.2
0.3
0.4
0.5
Con
vers
ion
rate
s
Kbs
Ksb
EFFECTS
Oil mobilization
Surfactant production
IFT reduction
Residual oil saturation
Relative permeability
Fractional flow
Option: Porosity reduction
Attachment
Microbial growth
Porosity reduction
Water relative permeability
Fractional flow
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PROFILE CHARACTERISTICS
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0.0 0.2 0.4 0.6 0.8 1.00.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
satu
ratio
n
sw (0.21 PVI) sor (0.21 PVI) sw (0.30 PVI) sor (0.30 PVI)
Two oil banks appear.
Injection Constant rate.Continuous.
Oil bank
RISK OF INLET CLOGGING
Two bacteria peaks.
Surfactant effect.
Inlet clogging risk.
Increased recovery.
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0.0 0.2 0.4 0.6 0.8 1.00.0
1.0x10-4
2.0x10-4
3.0x10-4
4.0x10-4
5.0x10-4
6.0x10-4
7.0x10-4
Vol
ume
frac
tion
Bac attached Bac water Metabolite water
0.32 PVI
0.0 0.2 0.4 0.6 0.8 1.00.0
1.0x10-4
2.0x10-4
3.0x10-4
4.0x10-4
5.0x10-4
6.0x10-4
7.0x10-40.48 PVI
Vol
ume
frac
tion
Bac attached Bac water Metabolite water
SLUG INJECTION SCHEME
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0.0 0.2 0.4 0.6 0.8 1.00.0
1.0x10-4
2.0x10-4
3.0x10-4
4.0x10-4
5.0x10-4
6.0x10-4
7.0x10-40.48 PVI
Vol
ume
frac
tion
Bac attached Bac water Metabolite water
subs
trat
e +
spor
es
subs
trat
e
wat
er s
lug
t1 t2
Slug injection scheme selected to avoid clogging and to concentrate attached bacteria in specific zones in the reservoir.
0.0 0.5 1.00.0
2.0x10-6
4.0x10-6
6.0x10-6
8.0x10-6
1.0x10-5
1.2x10-5
1.4x10-5
Vol
umet
ric c
once
ntra
tion
Bacteria att Bacteria water Substrate Metabolite water Spores water Spores att
0.67 PVI
0.0 0.5 1.00.0
5.0x10-5
1.0x10-4
1.5x10-4
2.0x10-4
2.5x10-4
3.0x10-4
3.5x10-4
4.0x10-4
0.82 PVI
Vol
umet
ric c
once
ntra
tion
Bacteria att Bacteria water Substrate Metabolite water Spores water Spores att
0.0 0.5 1.00.0
1.0x10-4
2.0x10-4
3.0x10-4
4.0x10-4
5.0x10-4
6.0x10-4
7.0x10-4
8.0x10-4
0.86 PVI
Vol
umet
ric c
once
ntra
tion
Bacteria att Bacteria water Substrate Metabolite water Spores water Spores att
0.0 0.5 1.00.0
1.0x10-4
2.0x10-4
3.0x10-4
4.0x10-4
5.0x10-4
6.0x10-4
7.0x10-4
8.0x10-4
9.0x10-4
0.94 PVI
Vol
umet
ric c
once
ntra
tion
Bacteria att Bacteria water Substrate Metabolite water Spores water Spores att
RELEASING PROCESS
22
Water slug induces conversion of attached bacteria to spores.
Rate of conversion is determined by released substrate and thus bacteria concentration.
REDUCTION OF CONVERSION RATE
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0.0 0.2 0.4 0.6 0.8 1.00.0
5.0x10-5
1.0x10-4
1.5x10-4
Volu
me fra
ctio
n
Bacteria att 0.6 Substrate 0.6 Bacteria att 0.5 Substrate 0.5 Bacteria att 0.4 Substrate 0.4
Waterslug
Waterslug
Waterslug
0.0 0.5 1.0 1.5 2.00.0
0.2
0.4
0.6
0.8
Rec
over
y
(PVI)
1e-3 2e-3 3e-3 4e-3 5e-3
Substrate concentrationSubstrate slug 0.07 PVI
Water slug 0.13 PVI
SUBSTRATE AND SLUGS
24
HIGH SUBSTRATE INJEC- TION CONCENTRATIONFaster MEOR responseSpore injection and spore-forming bacteria injection are similar
Waterflooding curve corresponds to 1e-3 curve.
SPORE-FORMING BACTERIA
25
SLUGS Reduced clogging risk Larger surfactant
production Improved utilization
of substrate Prolonged oil
mobilization
0.0 0.2 0.4 0.6 0.8 1.00.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Sat
urat
ion
sw NSP slug 0.20 sw SP slug 0.20 sor NSP slug 0.20 sor SP slug 0.20
second water front
SLUG INJECTION SCHEMES
26
High substrate injection concentration.
First slug is important for final recovery.
Improved utilization of substrate injected.
1.0 1.5 2.0
0.64
0.66
0.68
0.70
0.72
0.74
0.76
RF
(O
OIP
)
(PVI)
1 x slug 0.15 1 x slug 0.20 2 x slug 0.12 wslug 0.30 5 x slug 0.07 wslug 0.30 5 x slug 0.07 wslug 0.20 1 x slug 0.20 NSP 0.20 sub, 0.95 water, 0.06 sub 0.20 sub, 0.85 water, 0.06 sub
CONCLUSION
Spore-forming bacteria penetrate tight chalk better and may be used for MEOR.
Experimental discoveries lead to new MEOR features to investigate numerically:
Filtration type behavior (no biofilms)
Spore formation
Selective plugging
27
CONCLUSION Numerical simulations show that spore-forming bacteria have
the potential to avoid clogging due to sporulation.
High substrate injection concentration gives fast MEOR response.
Prolonged oil mobilization with water slugs due to substrate release from sporulation of attached bacteria.
It is possible to optimize the recovery by selecting right slug sizes and sequences
It is possible to deliver spores to a certain point at the reservoir and make them plugging there.
The first slug is the most important for final recovery.
28
QUESTIONS?Thank you for your attention.
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30
31
Measurement of k and , CT scan
Core Flooding Experimental Flow Chart
Core plug saturation under vacuum and high pressure
Methods
Core plug: Cleaning
Measurement of oil produced
Effluent
Bacterial counting
32
Methods
1. Injection of SS (2-3 PVI)2. Injection of crude oil until Swi
3. Injection of 1PV SS (1st SS)4. Injection of bacteria (1PV)5. Incubation (3 days)6. Injection of SS until Sor (2nd SS)7. Injection of nutrient (1PV)8. Incubation (7 days)9. Injection of SS (3rd SS)
Secondary
1. Injection of SS (2-3 PVI)2. Injection of crude oil until Swi
3. Injection of SS until Sor (1st SS)4. Injection of bacteria (1-3PV)5. Incubation (3 days)6. Injection of SS (2nd SS)
Tertiary
Different studies:
1. Injection of SS (2-3 PVI)2. Injection of crude oil until Swi
3. Aging – 3 weeks4. Injection of crude oil (2-3 PVI)5. Injection of SS until Sor (1st SS)6. Injection of bacteria (1-3PV)7. Incubation (3 days)8. Injection of SS (2nd SS)
Wett
abillity
33
Methods
Effluent (oil in brine)
Add 3ml toluene
Hand shake to dissolve the oil
Let the oil in toluene and brine seperate into two phases
Upper phase (oil in toluene) was decanted to a silica glass cuvette
Measure at UV-vis spectrophotometer at λ=750 nm
Oil Measurement ( Evdokimov et. al., 2002)
34
Results
• The UV/visible spectroscopy method relies on absorptivities of solid asphaltene aggregation in toluene solution.
• Fig. a shows good linear regression of the NO concentration vs. the absorbance data. The replicate samples showed similar linear regression trend line which means this method is quite stable and reproducible.
• This method can detect oil as low as 1 µl (Fig. b).
0 0.05 0.1 0.15 0.2 0.250
0.2
0.4
0.6
0.8
1
f(x) = 4.1227426046552 x + 0.0111858430033472R² = 0.997046095524364
200-1 µl fitLinear (200-1 µl fit)
oil (ml)
Opti
cal D
ensi
ty (7
50 n
m)
0
0.5
1
1.5
2
2.5
3
3.5NOLinear (NO)
oil (ml)
Ab
sorb
an
ce (
λ =
75
0n
m)
UV-vis methoda) b)
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Results
Core ID
k before (mD)
k after (mD)
Before
(%)
after (%)
26_water 3.2 2.8 30.8 30.726_3rd m 3.2 3.1 31.1 30.7
26_2nd m 3.1 3.2 30.7 30.8
26_aging 2.8 3.1 30.7 30.6
• Core 26 – homogenous reservoir chalk core• No significant change in k and before and after
experiment• No fractures based on CT scan results before and after
experiment
Core Plugs Properties
36
Results
• Experiment with an aged core gave 3.6% incremental oil, very slightly higher than non-aged core
Core no Sor (% OOIP)26_aging 48.6
Wettability alteration?
Total oil recovery: Aged core : 55.6%
0 3 6 9 12 15 18 21 24 27 30 330
20
40
60
80
100
core 26_water_1st SScore 26_water_2nd SScore 26_3rd method_1st SScore 26_3rd method_bacteriacore 26_3rd method_2nd SScore 26_aging_1st SScore 26_aging_bacteriacore 26_aging_2nd SS
PVI
cum
mul
ative
oil
prod
uctio
n (%
OO
IP)
0.4 % 3.2 %52.0%
NUMERICAL SOLUTION
Tanks-in-series approachMultivariable Newton iterationSequential procedure
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