Fate and effect of
produced water
from polymer floods
Contents
•
•
•
•
•
•
EOR?
Produced water?
Polymer?
Fate?
Effects?
Why are we researching this?
• Experimental work
Global impact?
Decision making,
regulations, politics
Biogeochemical
cycle
Polymer supply
chain.
Environmental impact?
Energy Budget?
•Traditional offshore water treatment are impacted by
polymer in PW. Flotation can handle polymers, however
(Compact) emusions are stronger with polymer or ASP present
making it less efficient.
Flotation
Settling
Hydrocyclone
Filtering
Polishing and
degradation
Remineralisation?
•Filters foul faster with polymer present. Sand filters are
very sensitive, Walnut shell filters are less sensitive.
Varieties of membranes require special treatments, but
are viable.
•Oxidation and post degradation of polymers in produced
water is being heavily investigated. Polishing is
recommended to remove residual COD before discharge.
Eutrophication,
Oxygen depletion,
Acidification?
Sequestration?
Human impact?
•At low concentrations, polymers enhance flocculation, at
higher concentrations, increased viscosity reduces
settling rate. Coagulation with trivalent cations produce
ample amounts of sludge that need further treatment.
•Hydrocyclone efficency are severly hampered by
polymers in water due to increased viscosity.
Gas and condensate
output
Onshore PW and waste
treatment, recycling?
Discharge to sea of treated PW
with concomitant polymer.
Water column
distribution? Sorption,
and Diffusion?
Aggregation and
sedimentation
Produced Water treatment
Secondary
Primary
Risk acceptable?
Use of biocides?
Increased Oil output,
Environmental
impact?
Physical degradation,
Hydrolyzation, Depolymerisation?
Metabolites? Recalcitrants?
Intermediates?
Ecosystem response?
Population response?
Exposure?
Absorption? Distribution?
Metabolism? Excretion?
Biodegradation?
Organism response to insult?
Adaptation? Toxicity?
Behavioral changes? Induction?
Stimulation?
Elimination? Retention time?
Resuspension?
Degradation? Inactivation?
Treated PW – Injection to
disposal well. Current best
available technique. Water
quality is important!
Reinjection of used polymer is a
good alternative. However the
risk of formation damage must
be carefully managed.
Water
Polymer
Oil
EOR?
 Primary recovery – oil goes
out by it self
 Oldest technology
 Secondary recovery – oil
needs assistance to get out
 Increased oil recovery (IOR) Water injection, gas injection,
gas lift
 Today’s technology
 Tertiary recovery – reservoir
needs manipulation to
release oil
 Enhanced oil recovery (EOR)
chemical stimulation
 Tomorrow’s technology
 For heavy oils
spe.org
Polymer flooding - mobility control
1. Increases
viscosity of
injected water
2. Reducing
fingering,
improving sweep
3. Better sweep
pushes out more
oil
~2 g/L polymer
Poor sweep
Improved sweep
Perfect sweep
Sweep efficiency, Source: http://juanesgroup.mit.edu
Global impact?
Decision making,
regulations, politics
Biogeochemical
cycle
Polymer supply
chain.
Environmental impact?
Energy Budget?
(Compact)
Flotation
•Traditional offshore water treatment are impacted by
polymer in PW. Flotation can handle polymers, however
emusions are stronger with polymer or ASP present
making it less efficient.
Settling
•At low concentrations, polymers enhance flocculation, at
higher concentrations, increased viscosity reduces
settling rate. Coagulation with trivalent cations produce
ample amounts of sludge that need further treatment.
Hydrocyclone
Filtering
Polishing and
degradation
•Hydrocyclone efficency are severly hampered by
polymers in water due to increased viscosity.
•Filters foul faster with polymer present. Sand filters are
very sensitive, Walnut shell filters are less sensitive.
Varieties of membranes require special treatments, but
are viable.
•Oxidation and post degradation of polymers in produced
water is being heavily investigated. Polishing is
recommended to remove residual COD before discharge.
Gas and condensate
output
Onshore PW and waste
treatment, recycling?
Remineralisation?
Eutrophication,
Oxygen depletion,
Acidification?
Sequestration?
Human impact?
Discharge to sea of treated PW
with concomitant polymer.
Water column
distribution? Sorption,
and Diffusion?
Aggregation and
sedimentation
Produced Water treatment
Secondary
Primary
Risk acceptable?
Use of biocides?
Increased Oil output,
Environmental
impact?
Physical degradation,
Hydrolyzation, Depolymerisation?
Metabolites? Recalcitrants?
Intermediates?
Ecosystem response?
Population response?
Exposure?
Absorption? Distribution?
Metabolism? Excretion?
Biodegradation?
Organism response to insult?
Adaptation? Toxicity?
Behavioral changes? Induction?
Stimulation?
Elimination? Retention time?
Resuspension?
Degradation? Inactivation?
Treated PW – Injection to
disposal well. Current best
available technique. Water
quality is important!
Reinjection of used polymer is a
good alternative. However the
risk of formation damage must
be carefully managed.
Water
Polymer
Oil
What’s up with the polymers? RA POV
 Tricky









Preparation
Characterization
Water treatment
Logistics
Monitoring
“Degradable” and non-toxic?
Exempt from REACH
Classification
Economic potential
 100:1 oil output vs polymer input
 Huge volumes
Common use of polyacrylamide, flocculation in water treatment.
(Source: Kemira advert)
Polymer flooding, notable examples
 Marmoul - Oman
 Daqing – China







Onshore
Full scale
100 % PW mitigation
No space limitation
10 % increase oil recovery
EOR from start
Easy/in situ logistics
http://www.2b1stconsulting.com/pdo-plans-for-marmul-polymer-projectphases-2-and-3/
Norwegian case




Offshore
Mature fields, No EOR
Industry in crisis
Produced water
management
 Platform design/space
limitations
 Logistics
 Precautionary regulations
BP - Ula
Regulative status, Norway (OSPAR)
Biopolymers on PLONOR list
Synthetic polymers <20% BOD28
Biopolymers = biocide?
Are biopolymers better if we need to compensate with biocide?
Produced water management?
100
% b io d e g r a d a t io n
•
•
•
•
•
50
S y n th e tic p o ly m e r
B io p o ly m e r
0
0
20
40
Day
60
80
Global impact?
Decision making,
regulations, politics
Biogeochemical
cycle
Polymer supply
chain.
Environmental impact?
Energy Budget?
(Compact)
Flotation
•Traditional offshore water treatment are impacted by
polymer in PW. Flotation can handle polymers, however
emusions are stronger with polymer or ASP present
making it less efficient.
Settling
•At low concentrations, polymers enhance flocculation, at
higher concentrations, increased viscosity reduces
settling rate. Coagulation with trivalent cations produce
ample amounts of sludge that need further treatment.
Hydrocyclone
Filtering
Polishing and
degradation
•Hydrocyclone efficency are severly hampered by
polymers in water due to increased viscosity.
•Filters foul faster with polymer present. Sand filters are
very sensitive, Walnut shell filters are less sensitive.
Varieties of membranes require special treatments, but
are viable.
•Oxidation and post degradation of polymers in produced
water is being heavily investigated. Polishing is
recommended to remove residual COD before discharge.
Gas and condensate
output
Onshore PW and waste
treatment, recycling?
Remineralisation?
Eutrophication,
Oxygen depletion,
Acidification?
Sequestration?
Human impact?
Discharge to sea of treated PW
with concomitant polymer.
Water column
distribution? Sorption,
and Diffusion?
Aggregation and
sedimentation
Produced Water treatment
Secondary
Primary
Risk acceptable?
Use of biocides?
Increased Oil output,
Environmental
impact?
Physical degradation,
Hydrolyzation, Depolymerisation?
Metabolites? Recalcitrants?
Intermediates?
Ecosystem response?
Population response?
Exposure?
Absorption? Distribution?
Metabolism? Excretion?
Biodegradation?
Organism response to insult?
Adaptation? Toxicity?
Behavioral changes? Induction?
Stimulation?
Elimination? Retention time?
Resuspension?
Degradation? Inactivation?
Treated PW – Injection to
disposal well. Current best
available technique. Water
quality is important!
Reinjection of used polymer is a
good alternative. However the
risk of formation damage must
be carefully managed.
Water
Polymer
Oil
Produced water – An unhealthy mix
 Organics, solved or
emulsified




BTEX
Fatty acids/soaps
Aromatics
Aliphates
 Production chemicals
 Inorganics
 Heavy metals
 Salts
 NORM
 Particulates
 Clay, silicates, waxes, scale,
NORM
Norwegian petroleum museum/Statoil: Øyvind Hagen
Back produced polymer
•
•
•
•
Years of migration
50-80 % mass recovery of injected polymer (~1500 g/L)
Partly degraded – Still viscosifying /
Changes PW composition?
Produced water management
•
•
•
•
Hydrocyclones
Compact flotation (CFU)
C’Tour
Micro porous polymer
extraction
• Emulsion breakers/coalescence
• Radioactive material removal
• Injection of produced water
• However, PF reduces water cut
http://www.npd.no/no/Publikasjoner/Rapporter/Miljoteknologi/4-Produksjon/#4.6.4
Offshore, dedicated reinjection
• Have 80 % reinjection rates today
• Aim towards 95 % in coming years
• Very sensitive to quality of injected
water
• For polymer flooding offshore – est.
95-98 % «up» time
How much polymer are we talking about?
1.
Johan Sverdrup – A new field for EOR
- 1,7 to 3,3 billion barrels of oil
2.
400 ppm polymer per pore volume = 652 000 t
3.
Worst case: 100 % recovery of polymer and discharge 5 % of
PW
4.
50 year lifetime
5.
Amounts to 560 t/y
6.
Equals 2 % of all chemicals released offshore every year (NO)
Global impact?
Decision making,
regulations, politics
Biogeochemical
cycle
Polymer supply
chain.
Environmental impact?
Energy Budget?
(Compact)
Flotation
•Traditional offshore water treatment are impacted by
polymer in PW. Flotation can handle polymers, however
emusions are stronger with polymer or ASP present
making it less efficient.
Settling
•At low concentrations, polymers enhance flocculation, at
higher concentrations, increased viscosity reduces
settling rate. Coagulation with trivalent cations produce
ample amounts of sludge that need further treatment.
Hydrocyclone
Filtering
Polishing and
degradation
•Hydrocyclone efficency are severly hampered by
polymers in water due to increased viscosity.
•Filters foul faster with polymer present. Sand filters are
very sensitive, Walnut shell filters are less sensitive.
Varieties of membranes require special treatments, but
are viable.
•Oxidation and post degradation of polymers in produced
water is being heavily investigated. Polishing is
recommended to remove residual COD before discharge.
Gas and condensate
output
Onshore PW and waste
treatment, recycling?
Remineralisation?
Eutrophication,
Oxygen depletion,
Acidification?
Sequestration?
Human impact?
Discharge to sea of treated PW
with concomitant polymer.
Water column
distribution? Sorption,
and Diffusion?
Aggregation and
sedimentation
Produced Water treatment
Secondary
Primary
Risk acceptable?
Use of biocides?
Increased Oil output,
Environmental
impact?
Physical degradation,
Hydrolyzation, Depolymerisation?
Metabolites? Recalcitrants?
Intermediates?
Ecosystem response?
Population response?
Exposure?
Absorption? Distribution?
Metabolism? Excretion?
Biodegradation?
Organism response to insult?
Adaptation? Toxicity?
Behavioral changes? Induction?
Stimulation?
Elimination? Retention time?
Resuspension?
Degradation? Inactivation?
Treated PW – Injection to
disposal well. Current best
available technique. Water
quality is important!
Reinjection of used polymer is a
good alternative. However the
risk of formation damage must
be carefully managed.
Water
Polymer
Oil
The polymers are
•
•
•
•
•
Very high molecular weight, >10 Mda
Linear random co- or ter- polymers
Hydrophilic
Viscosifying at low concentrations
Chemically stable polymers are preferred
Structure
H2N
O
HO
C
N
CH3
CH2
CH3
n
Acrylamide (AM)
O
H2C
CH3
n
H 2C
O
CH2
HO
O
O
OH
n
Acrylamido Tert-butyl Sulfonate (ATBS)
O
O
OH
HO
CH3
O
HO
OH
O
O
CH3
n
Acrylic acid (AA)
HO
S
NH
CH2
OH
O
H3C
C
O
Vinylpyrrolidone (NVP)
O
OH
Biopolymers: pullulan, xanthan, scleroglucans
OH
n
Global impact?
Decision making,
regulations, politics
Biogeochemical
cycle
Polymer supply
chain.
Environmental impact?
Energy Budget?
(Compact)
Flotation
•Traditional offshore water treatment are impacted by
polymer in PW. Flotation can handle polymers, however
emusions are stronger with polymer or ASP present
making it less efficient.
Settling
•At low concentrations, polymers enhance flocculation, at
higher concentrations, increased viscosity reduces
settling rate. Coagulation with trivalent cations produce
ample amounts of sludge that need further treatment.
Hydrocyclone
Filtering
Polishing and
degradation
•Hydrocyclone efficency are severly hampered by
polymers in water due to increased viscosity.
•Filters foul faster with polymer present. Sand filters are
very sensitive, Walnut shell filters are less sensitive.
Varieties of membranes require special treatments, but
are viable.
•Oxidation and post degradation of polymers in produced
water is being heavily investigated. Polishing is
recommended to remove residual COD before discharge.
Gas and condensate
output
Onshore PW and waste
treatment, recycling?
Remineralisation?
Eutrophication,
Oxygen depletion,
Acidification?
Sequestration?
Human impact?
Discharge to sea of treated PW
with concomitant polymer.
Water column
distribution? Sorption,
and Diffusion?
Aggregation and
sedimentation
Produced Water treatment
Secondary
Primary
Risk acceptable?
Use of biocides?
Increased Oil output,
Environmental
impact?
Physical degradation,
Hydrolyzation, Depolymerisation?
Metabolites? Recalcitrants?
Intermediates?
Ecosystem response?
Population response?
Exposure?
Absorption? Distribution?
Metabolism? Excretion?
Biodegradation?
Organism response to insult?
Adaptation? Toxicity?
Behavioral changes? Induction?
Stimulation?
Elimination? Retention time?
Resuspension?
Degradation? Inactivation?
Treated PW – Injection to
disposal well. Current best
available technique. Water
quality is important!
Reinjection of used polymer is a
good alternative. However the
risk of formation damage must
be carefully managed.
Water
Polymer
Oil
Toxicity - Standardized eco-toxicity tests
• Acute:
–
HPAM EC50 >100 mg/L
–
NOEC >10 mg/L
–
Cationic and hydrophobically associating polymers are very different from
negative or uncharged polymers
• Chronic:
–
LOEC 10 mg/L
• Very limited knowledge other than the above
All tox-studies must be read with extreme care and databases
like echemportal gets everything wrong, consistently.
Global impact?
Decision making,
regulations, politics
Biogeochemical
cycle
Polymer supply
chain.
Environmental impact?
Energy Budget?
(Compact)
Flotation
•Traditional offshore water treatment are impacted by
polymer in PW. Flotation can handle polymers, however
emusions are stronger with polymer or ASP present
making it less efficient.
Settling
•At low concentrations, polymers enhance flocculation, at
higher concentrations, increased viscosity reduces
settling rate. Coagulation with trivalent cations produce
ample amounts of sludge that need further treatment.
Hydrocyclone
Filtering
Polishing and
degradation
•Hydrocyclone efficency are severly hampered by
polymers in water due to increased viscosity.
•Filters foul faster with polymer present. Sand filters are
very sensitive, Walnut shell filters are less sensitive.
Varieties of membranes require special treatments, but
are viable.
•Oxidation and post degradation of polymers in produced
water is being heavily investigated. Polishing is
recommended to remove residual COD before discharge.
Gas and condensate
output
Onshore PW and waste
treatment, recycling?
Remineralisation?
Eutrophication,
Oxygen depletion,
Acidification?
Sequestration?
Human impact?
Discharge to sea of treated PW
with concomitant polymer.
Water column
distribution? Sorption,
and Diffusion?
Aggregation and
sedimentation
Produced Water treatment
Secondary
Primary
Risk acceptable?
Use of biocides?
Increased Oil output,
Environmental
impact?
Physical degradation,
Hydrolyzation, Depolymerisation?
Metabolites? Recalcitrants?
Intermediates?
Ecosystem response?
Population response?
Exposure?
Absorption? Distribution?
Metabolism? Excretion?
Biodegradation?
Organism response to insult?
Adaptation? Toxicity?
Behavioral changes? Induction?
Stimulation?
Elimination? Retention time?
Resuspension?
Degradation? Inactivation?
Treated PW – Injection to
disposal well. Current best
available technique. Water
quality is important!
Reinjection of used polymer is a
good alternative. However the
risk of formation damage must
be carefully managed.
Water
Polymer
Oil
Marine fate, discharged produced water
• Stays in a plume that sinks before reaching equal
density with sea water
• Diluted 1000 times within a km – 1,5 ppm @ 1000 m
• Diluted 100 times within 100 meters – 15 ppm @ 100
m
• For comparison, some studies have measured
lipophilic PAH’s as far as 30 km from source
• Most LMW components biodegraded within the first
few days/km’s
Marine fate, polymers
• High ionic and HMW polymers
precipitate
• Low ionic and LMW stay solved
• Can adsorb to clays and soils at 1
mg/g
– Adsorption increases with:
• Molecular weight
• Salinity
Picture - 100 ppm polyacrylic acid in sea
water
Degradation, synthetics
• Rapid biodegradation <octamers
• No biodegradation >2 kDa
• Vulnerable to physical degradation:
–
UV, ROS, iron, shear, temperature
• Development of hard to degrade polymers encouraged
• Claims of hydrolyzation/deamination occuring rapidly in
induced bacterial cultures
• No suggested pathways
Experimental work
Where to begin?
Global impact?
Decision making,
regulations, politics
Biogeochemical
cycle
Polymer supply
chain.
Environmental impact?
Energy Budget?
(Compact)
Flotation
•Traditional offshore water treatment are impacted by
polymer in PW. Flotation can handle polymers, however
emusions are stronger with polymer or ASP present
making it less efficient.
Settling
•At low concentrations, polymers enhance flocculation, at
higher concentrations, increased viscosity reduces
settling rate. Coagulation with trivalent cations produce
ample amounts of sludge that need further treatment.
Hydrocyclone
Filtering
Polishing and
degradation
•Hydrocyclone efficency are severly hampered by
polymers in water due to increased viscosity.
•Filters foul faster with polymer present. Sand filters are
very sensitive, Walnut shell filters are less sensitive.
Varieties of membranes require special treatments, but
are viable.
•Oxidation and post degradation of polymers in produced
water is being heavily investigated. Polishing is
recommended to remove residual COD before discharge.
Gas and condensate
output
Onshore PW and waste
treatment, recycling?
Remineralisation?
Eutrophication,
Oxygen depletion,
Acidification?
Sequestration?
Human impact?
Discharge to sea of treated PW
with concomitant polymer.
Water column
distribution? Sorption,
and Diffusion?
Aggregation and
sedimentation
Produced Water treatment
Secondary
Primary
Risk acceptable?
Use of biocides?
Increased Oil output,
Environmental
impact?
Physical degradation,
Hydrolyzation, Depolymerisation?
Metabolites? Recalcitrants?
Intermediates?
Ecosystem response?
Population response?
Exposure?
Absorption? Distribution?
Metabolism? Excretion?
Biodegradation?
Organism response to insult?
Adaptation? Toxicity?
Behavioral changes? Induction?
Stimulation?
Elimination? Retention time?
Resuspension?
Degradation? Inactivation?
Treated PW – Injection to
disposal well. Current best
available technique. Water
quality is important!
Reinjection of used polymer is a
good alternative. However the
risk of formation damage must
be carefully managed.
Water
Polymer
Oil
Light scattering - A physical measurement
The MALLS
Respirometry
Polyacrylic acids
Propionic acid
PAAC 2kDa
PAAC 50kDa
PAAC 450kDa
PAAC 4MDa
Xa
% biodegradation
100
50
0
Sample
0
20
40
Day
60
80
Concentration ppm
PA 2 kDa
47
PA 50 kDa
27
PA 450 KDa
10
PA 4 MDa
10
Xanthan 2 MDa
33
Propionic acid
70
Tangential flow filtration
Preliminary results, 80 day biodeg.
Before
After
log differential molar mass
PAAC 50k new stock[Samples sept. 2016]
untitled002[Samples sept. 2016]
log differential molar mass
PAAC 450k new stock[Samples sept. 2016]
XA new stock[Samples sept. 2016]
PAAC 2k conc[Samples sept. 2016]
PAAC 450k conc[Samples sept. 2016]
2.5
differential weight fraction (1/log(g/mol))
differential weight fraction (1/log(g/mol))
2.5
PAAC 50k conc[Samples sept. 2016]
2.0
1.5
1.0
0.5
0.0
2.0
1.5
1.0
0.5
0.0
1000.0
1.0x10
4
5
1.0x10
Molar Mass (g/mol)
1.0x10
6
1000.0
1.0x10
4
5
1.0x10
Molar Mass (g/mol)
1.0x10
6
Recovery
Polymer
2k
50k
450k
4m
xa
conc mg/L recovery
47,09
51 %
26,95
30 %
10,14
35 %
10,13
9%
32,36
3%
O th e r s p e c ie s
60
AM PS 2M
AN 125
PVP 1M
% deg
40
PVP 40k
XA 2M
5115 VH M
20
0
Sample
0
20
40
Days
60
80
AMPS 2M
AN 125 VHM
5115 VHM
PVP 40 k
PVP 1 M
Xa
Concentration
ppm
48
53
47
62
52
73
Summary
• Tough to choose between biopolymer or synthetic
• Guaranteed reemergence and adverse effect on PW treatment
gives significant risk of discharge of substantial amounts of polymer
• EOR-Polymers are not very toxic, but no mechanistic knowledge
• Nor do they degrade biologically, but seem degrade eventually
through other means
• Large knowledge gaps are due to analytical limitations and nature
of polymers
• Light scattering can be used with caution
• It is possible to measure low concentrations of polymer in dirty
samples, but needs refinement
Aknowledgements
• The authors acknowledge the Research Council of Norway
and the industry partners; ConocoPhillips Skandinavia AS,
BP Norge AS, Det Norske Oljeselskap AS, Eni Norge AS,
Maersk Oil Norway AS, DONG Energy A/S, Denmark, Statoil
Petroleum AS, ENGIE E&P NORGE AS, Lundin Norway
AS, Halliburton AS, Schlumberger Norge AS, Wintershall
Norge AS of The National IOR Centre of Norway for support.
• SNF Floerger and colleagues at IPREM at the University of
Pau