Force workshop 6-7 Nov 2013 Competence... · Force workshop 6-7 Nov 2013. ... pressure maintenance 80 %RF CIPR ... Water or Gas injection 40 to 50% Water injection 20 to 30% Water

Polymer flooding - an option for NCS?

Arne Skauge

CIPR, Uni Research

14:30 – 15:15

CIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCHCIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCH

News in the R&D front - New possibilitiesForce

workshop 6-7 Nov 2

013

OilOil RecoveryRecovery FactorFactor

Primary production

Primary and secondary recovery leads to an average RF of 35%

Secondary recovery

Natural flow and artificial lift techniques (pumps)

Water or Gas Injection ; pressure maintenance

80%RF

CIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCH

40 to 50%

Wateror Gas

injection

40 to 50%

Waterinjection 20 to 30%

Waterinjection

5-20% Water injection

Worldwide Average RF ~35%

20

40

80

60

%RF

Oil viscosity (cp)0.1 1 10 100 103 104

OIL VISCOSITY (µµµµo) ��

%RF

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hop 6-7 Nov 2013


Primary production

Secondary recovery Tertiary recoveryChemical

Polymer Flooding:

� Improves initial sweep efficiency

� Prevents early fingering

� Water cut reduction compensates for the cost of chemicals

80%RF

Expectations on the efficiency of polymer based floods


40 to 50%

Wateror Gas

injection

40 to 50%


Waterinjection


RF ~70%

Oil viscosity (cp)

+5 to 15%Polymer only

+5 to10% Polymer only20

40

80

60

%RF

0.1 1 10 100 103 104


%RF

+ 5- 10%+ additional recovery by polymer from lower µµµµo

heterogeneous systems

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hop 6-7 Nov 2013


Primary production

Secondary recovery Tertiary recoveryChemical

Polymer Flooding:

� Improves initial sweep efficiency

� Prevents early fingering

� Water cut reduction compensates for the cost of chemicals

80%RF

Expectations on the efficiency of polymer based floods


40 to 50%

Wateror Gas

injection

40 to 50%


Waterinjection


RF ~70%

Oil viscosity (cp)

+5 to 15%Polymer only

+5 to10% Polymer only20

40

80

60

%RF

0.1 1 10 100 103 104


%RF

+ 5- 10%+ additional recovery by polymer from VERY HIGH µµµµo

in Alberta+ - heavy oil

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Polymer Sweep Efficiency in Reservoirs

The profile of “incremental oil” in Polymer flooding

CIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCH 5

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Reservoir Screening CriteriaWhere Polymer Flooding Could be Applied (1991)

1991

ScreeningCriterion

Visc. controlpolymer flood

Het. controlpolymer flood Comment

CIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCHCIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCH 6

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Reservoir Screening CriteriaWhere Polymer Flooding Could be Applied (1991)

1991

ScreeningCriterion

Visc. controlpolymer flood

Het. controlpolymer flood Comment

CIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCHCIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCH 7

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Experiment E2000

Slab dimensions (cm) 30 x 29,8 x 2,55

x = 30 cm

y = 30 cm

z = 2 cm

injection

x x x

1 2 3

Polymers for heavy oil

Porosity 0,248

Pore Volume, PV (ml) 546

Swi 0,13

kw(Sw = 1) (Darcy) 2,3

Oil viscosity (cP) 2000

Injected Volumes (PV):

Water flood (PV) 2,3

Polymer flood (PV) 1,5

Polymer viscosity

58 cP at 10s-1

24 cP at 70s-1

Polymer 3630S

Skauge, A., Ormehaug, P.A., Vik, B.F., Fabbri, C., Bondino, I, and Hamon, G., Polymer Flood Design for Displacement of Heavy Oil analysed by 2D-imaging, EAGE 17th European Symposium on Improved Oil Recovery, St. Petersburg, Russia, 16 - 18 April 2013

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Technical data for measuring system

- X-ray adsorption

- Gamma adsorption

- X-ray camera

Saturation estimation methods

CIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCHCIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCHCentre for Integrated Petroleum Research, Bergen, Norway

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CIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCHCIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCHCentre for Integrated Petroleum Research, Bergen, Norway

Example viscous fingering at the model inlet

Pictures from X-ray camera

Slabs up to 1meter x 1meter

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2D-experiments using X-ray detection

Material: Bentheimer slabs 30cm x 30cm x 2 cm

Type of fingering observed during unstable displacement

Adverse mobility ratio floods

CIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCHCentre for Integrated Petroleum Research, Bergen, Norway

Sharpening (1) Spreading (2) Indifferent (3)

1. Sharpening fingers grow from the tip of the finger and established fingers is reinforced

(observed for miscible displacement when the mobility ratio was unfavourable [viscosity ratio 100 : 1])

2. Spreading fingers increase the area contacted with frontal displacement, thicker front)(observed when water was injected at 100% oil saturation and strong spontaneous water imbibition occur)

3. Indifferent process - no visible fingers appears even at very unfavourable mobility ratio (observed for waterflooding at Swi, both at high and low interfacial tensions)

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Waterflood E2000

Viscous water fingers develops into channels at later stage

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OBSERVATIONS

Fractal type fingers is formed at early stage of the

waterflood

Early breakthrough of water (0,04 PV)Early breakthrough of water (0,04 PV)

Fingers is broadened and the stronger fingers progress

Fingers collapse into channels at later stage

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Water- and polymer flood

40

50

60

70

Oil R

ec

ov

ery

(%

OO

IP)

Polymer both increase oil recovery and accelerate production

0

10

20

30

40

0 1 2 3 4 5 6 7 8 9

Injected Volume (PV)

Oil R

ec

ov

ery

(%

OO

IP)

E7000

E2000Force

workshop 6-7 Nov 2

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Oil mobilization during polymer flood

X-ray camera visualize change in oil and water saturation

2000 cP oil Change in saturations after end of waterflood

Red: increased oil saturation

Light blue: increased water saturation

Early oil mobilization through established water channels

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Change in local oil saturation during waterflood

Water channels reach low So early

Oil saturation at the end of waterflood

Sorw=0,25

Water channels reach low So early

No change in So

In unswept areas

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Oil saturations

in water channels

Position:

Border of a water

channel

Polymer flood 1,5 PV

Oil

bank

Polymer swept area

Position:

Center of a

water channel

Oil saturation at the end of polymer flood0,25 PV

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Effluent production

P C P C

First polymer slug (0.5 PV) seems sufficient slug size for maximizing oil production

Li tracer in chase water has a breakthrough around 0.5 PV

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Polymers for EOR

BIOPOLYMERS SYNTHETIC POLYMERS

19

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“Polyacrylamide” or “HPAM” Polymers

[ - CH2 - CH - ]m - [ - CH2 - CH - ]n

C C

- O O O NH2

acrylate acrylamide

“Polyacrylamide” or “HPAM” Polymers

[ - CH2 - CH - ]m - [ - CH2 - CH - ]n

C C

- O O O NH2

acrylate acrylamide

Polymers


XanthanPolysaccharide

Double helix, semi-rigid rod.

Flexible coil

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Polymer Structure

Conformation of HPAM in high and low salinity

HPAM is a polyelectrolyte - polyanionic

21

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Polymer Structure

Structure of HPAM - degree of hydrolysis

22

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Polymer Structure

HPAM - degree of hydrolysis with ageing

23

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AM: acrylamide

Code name type AM/AA AMPS n-VP

Superpusher SAV 522 n-VP Polymer 4 25-45% 20-25% 35-50%

Superpusher SAV 301 n-VP Polymer 3 50-65% 20-25% 15-25%

DP/GC 2878-6 n-VP Polymer 2 60-70% 20-25% 10-15%

DP/GC 2878-3 n-VP Polymer 1 65-75% 20-25% 5-10%

AN 125 SH AMPS Polymer 75-80% 20-25%

Flopaam 3630S F3P HPAM Polymer+ 100 %

Examples of high temperature and high salinity polymers

Salttolerance

Tempstability

New polymers

Best choice of polymer


AA: acrylate

AMPS: 2-Acrylamido-2-Methylpropane Sulfonate

n_VP: n-Vinyl Pyrrolidone

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Viscosity as a function of aging time for HPAM and AN132Conditions: 80ºC, 5 wt. % NaCl included 3 wt. % IBA, Viscosity at a shear rate of 100 s-1



Sulfonation degree increase thermal stability

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Some positive news about salinity tolerant polymers

Effect of sulfonationdegree on viscosity and retention in saline brine

Retention

AN132 ~ 1/10 HPAM



•

Hydrolysed PolyAcrylaMide

different sulfonationdegrees

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Polymer retention – influence onpolymer flow in porous media

Straining

Bridging adsorption

Flow-induced adsorption


Hydrodynamic retention

Depleted layer

Inaccessible pore volume (IPV)

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Straining

Bridging adsorption




Depleted layer

Inaccessible pore volume (IPV)

May lead to:

- Blocking of pore space (IPV)

- Early break-through

- Plugging / pressure increase

- Varying polymer concentration in effluent

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Straining

Bridging adsorption




Depleted layer

Inaccessible pore volume (IPV)During extensional flow – bridging or multilayeradsorption (Chauveteau and co-workers)

May lead to:

- Blocking of pore space (IPV)


- Face plugging / injectivity reduction

- Increased loss of polymer

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Straining

Bridging adsorption




Depleted layer

Inaccessible pore volume (IPV)«Slip effect» -mixed effect, depends on severalfactors

May lead to:


- Poor sweep

- Decreased viscosity at Newtonian flow

- Increased effective shear rate

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No adsorption, No IPV 20 % PV adsorption, No IPV


0 % PV adsorption, 25 % PV IPV 20 % PV adsorption, 25 % PV IPV

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Fluid models for viscoelasticity

η

a b c d e f g

CIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCHCIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCHγ

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UVM

η

CIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCHCIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCHγ

Power law Ellis

Carreau

Stavland

γ

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� Power law

� Ellis model

� Carreau equation


� Carreau equation

� UVM

� Stavland

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Low salinity polymer

Viscosities: Oil: 2,4cP LS brine: 1,03cP Polymer: 2,6cP


Source: Behruz Shiran and Arne Skauge, 2012

High salinity WF

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Example – nano particle polymersSandstone reservoir core (fresh core), K=900 mD

0.5

0.6

0.7

0.8

0.9

Oil R

eco

very

(H

CP

V)


0

0.1

0.2

0.3

0.4

0.00 5.00 10.00 15.00 20.00 25.00 30.00

Volume injected (PV)

Oil R

eco

very

(H

CP

V)

waterflood LPSForce

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In Out

Micro channel

Velocity vectors in a rectangular micro channel

Polymer particle trackingMicromodels and m-PIV (particle image velocimetry)


z1

z2

Z …

zN

plane 1

plane 2

plane …

plane N

(Xi,j, yi,j)

In

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Polymer Sweep Efficiency in Reservoirs

Linear displacement efficiency (Buckley-Leverett)DO POLYMERS REDUCE RESIDUAL OIL below Sor ???Chinese school of thought on this also ….

Xia et al, SPE 114335 claim in Exptl. + Modelling Study Mechanism of the Effect of Microforces on Residual Oil in Chemical Flooding

Sor reduction as function of Weissenberg No., We = xxx

CIPR – CENTRE FOR INTEGRATED PETROLEUM RESEARCH 38

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Example of game changer

Polymer floodingTraditionally polymer is injected for sweep improvement

Old rules of tumbs

Poor injectivity (a lot of positive results on injectivity are now available)

Little effect after extensive waterflooding (new results disprove this statement)


this statement)

Have to modify the viscosity ratio extensively (new results disprove this statement)

Additional news

Effect on microscopic displacement (lower Sor)

(viscoelastic effects, etc)

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Documents

Force workshop 6-7 Nov 2013 Competence... · Force workshop 6-7 Nov 2013. ... pressure maintenance 80 %RF CIPR ... Water or Gas injection 40 to 50% Water injection 20 to 30% Water