Harry L. Chang
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Transcript Harry L. Chang
Chemical EOR Progress in China
Advances and Challenges
Harry L. Chang
[email protected]
www.chemortech.com
Outline of Presentation
Overview
Recent advancements
Chemical EOR in China
Polymer flooding
ASP flooding
Facilities
Some controversial issues and
challenges
Summary
Chemical EOR Global Status
China has most field experiences
US has focused on improvements in
chemicals, lab studies, and simulators
Increased chemical EOR mechanistic
understandings and field activities in US
and world-wide in recent years
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General Understanding
Polymer flooding (PF): A mature EOR process
Polymer gels: Used successfully in water shutoff and profile modification in selected reservoirs
Surfactant-polymer (SP): Effective but expensive
ASP: Effective, less expensive, but requires
extensive treatment of injection/produced fluids
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Recent Advancements
Chemicals
Laboratory Studies
Simulation and Simulators
Project Design and Implementation
Facilities, Monitoring, and Evaluation
More Field Experiences
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EOR Chemicals
Polymers and related chemicals
Surfactants
Co-surfactants
Co-solvents
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Improvements on Polymers
(UT David Levitt Dissertation)
50
40
1500 ppm HPAM polymer, 23 °C, 11 s-1
Viscosity [cp]
30
NaCl
20
9:1 NaCl/CaCl2
10
0
0
50,000
100,000
150,000
200,000
Electrolyte Concentration [TDS, ppm]
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Improved Laboratory Techniques
Phase behavior/solubalization ratio
High temperature and live oil
Core flood techniques
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Phase Behavior Experiments
• Phase behavior experiments
– Inexpensive technique for surfactant formulation
– Measure solubalization parameters/IFT’s
– Measure coalescence/equilibration time
– Determine microemulsion viscosities
• Specific surfactant(s) can be tailored for specific oils
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An Excellent ME Phase Behavior
Salinity, %: 0.0 0.5 0.75 1.0 1.25 1.5 1.75 2.0 2.25 2.5 2.75 3.0 3.5 4.0
Interface Fluidity
Increasing Electrolyte Concentration
Core Flooding
High oil recovery
>90% Sorw, or Sorc<0.04
Adequate mobility control
Good surfactant/polymer transport
Low surfactant retention
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Simulation and Simulators
Mechanistic model for core flood and
pattern simulation
Calibration and field scale simulation
Advanced simulators
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Chemical EOR in China
Daqing Oilfield
Largest polymer and ASP floods in the world
PF oil production in Daqing has been
stabilized at ~200,000 bbl/d over 10 years
Polymer requirement has doubled in last 10
years from ~80,000 t/yr to ~160,000 t/yr
Large-scale ASP floods have been
implemented since 2006
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Shengli Oilfield
Second largest PF in China
Also has polymer manufacturing
facilities
Several ASP pilot tests have been
conducted in the past but decided to
use SP instead
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PF in China Showed
Incremental recovery depends on
reservoir quality
polymer selection
polymer amount, > 500 ppm.pv now
Production of polymer and emulsions may be
expected
Large scale injection/production facilities are
necessary for successful operations
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Polymer Flooding also Showed
Simplified field operations have been practiced in
field-wide operations
On-site polymer production would improve the
economics
KYPAM polymers appears to be more effective in
high perm and high salinity reservoirs
Visco-elastic behavior can reduce Sor (SPE127453)
CDG will enhance PF performance
Harry L. Chang
Oil Production by Polymer Flooding
Daqing Oilfield, China
O il R a te b y Po ly m e r F lo o d i n g , m m b b ls
1000
900
P F A n n . R a te , m m b b ls
800
C u m . P ro d ., m m b b ls
700
600
500
400
300
200
100
0
1993
1995
1997
1999
2001
Y e ar
2003
2005
2007
2009
A Typical PF Field Performance
Typical Pressure and Polymer Production
Oil Production by Polymer Flooding
Shengli Oilfield, China
200
P F A n n . R a te , m m b b ls
O il R a te b y P o ly m e r F lo o d in g , m m b b ls
180
C u m . P ro d ., m m b b ls
160
140
120
100
80
60
40
20
0
1997
1999
2001
2003
Ye a r
2005
2007
2009
KYPAM Polymers
Comb like with short branched chain to
maintain effectiveness in high salinity
brines
Wide MW range for reservoirs with
different permeabilities
Successfully applied in some reservoirs
in China
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viscosity
Viscosity Data of KYPAM Polymer
Concentration
Performance of KYPAM Polymers
Performance of KYPAM Polymers
ASP Floods in China
Pilot testing: Daqing, Shengli, Karamay
Large scale field projects in Daqing
Large scale injection/production facilities
have been developed in Daqing
Emulsion and scale productions were
observed
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Field Examples
Daqing
Karamay
ASP pilot simulation
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ASP Pilot Tests Conducted in
Daqing Oilfield
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ASP Results in Daqing
High incremental recovery
Severe emulsion production
Severe scale production
SP with A instead of ASP?
One of the most difficult oil for SP
flooding
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Karamay ASP Pilot Test Design and
Field Performance
(SPE 64726)
Process design/management: Harry
Chang
Project implementation: Karamay Oilfield
A single surfactant system using
petroleum sulfonates produced in a local
refinery
Applied the salinity gradient with STPP
for sequestration
ASP Pilot Test Well Pattern, 2Z-B9-3 Well Group
Karamay Oil Field (SPE 64726)
ASP Slug Design and Injection Sequence
(SPE 64726)
PAM
PAM
Modelling Core Flood - Karamay ASP Project
Modelling Coreflood (UTCHEM) - Karamay ASP
Project
Modelling of Pilot Area Performance
(SPE 39610 and 64726)
Some Comments on ASP
ASP requires special crude oils to improve
performances
ASP slug cost less but other costs would be
substantial (treating injection brine and
produced fluids)
Low surfactant concentration (<0.5% active)
SP formulations are available now
Some ASP projects may be just SP with A or
just P
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Chemical Injection Facilities
SPSW vs. SPMW injection facilities
Large-scale polymer dispersion/mixing
Large-scale ASP injection facilities
Emulsion treatment facilities
Fully automatic modular units for pilot
testing
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A Polymer Test Injection Site, SPSW Facilities
SPMW Polymer injection system
Spec.: 16 Mpa, 60 m3/hr, polymer
conc., 1000 mg/l,27 injection
wells
SPMW Polymer injection
pumps
Spec.: 16 Mpa, 4 m3/hr,
And 5000 mg/l polymer
ST200508
SPE Logo
40
Large-Scale Polymer Dispersion/Mixing
41
Polymer Dispersion
Polymer Mixing
ASP Injection Units Prior to Shipping
An ASP Injection Station with 70 Wells
Produced Fluid Treatment Facilities
ASP Produced Fluid Treatment, 24,000 m3/d
A Fully Automatic Modular Pre-Factory Tested
ASP Pilot Injection Facility
Designed Rate: 640 m3/day
Designed Pressure: 12 Mpa
Chemical Processing Includes:
•
•
•
•
•
•
•
•
Dry polymer handling, processing, & maturation
Dry soda ash handling, processing, & dissolution
Surfactant handling & metering
Water conditioning chemicals (oxygen scavenger and biocide)
Nitrogen blanket
•
R-O water softening
Fe removal system
Heat exchanger system for high temp fluid injection
• Automation: Allen-Bradley PLC based with full PID Loop
control for accurate chemical recipe control and data
collection
• Special Systems Included:
•
•
SPE Logo
47
A Polymer Handling System Designed by
Chemor Tech and Fabricated by
Dafeng/COT in China
ST200508
SPE Logo
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ST200508
SPE Logo
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ST200508
SPE Logo
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ST200508
SPE Logo
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SOME CONTROVERTIAL ISSUES
Polymer dispersion
Is fully hydration on the surface necessary?
are oxygen scavenger and nitrogen blanket
necessary?
Polymer flooding vs. weak gels
ASP vs. SP
Is ASP the future?
Why SP has not been emphasized?
ASP and SP Slug Aqueous Phase
Stability/Clarity?
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Challenges
New polymers for high temperatures (>90oC
Modeling polymer visco-elastic effects
Low MW polymers for low perm. reservoirs
Surfactants with low adsorption and other
additives
Low cost and effective emulsion breakers
New scale prevention technologies
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Summary
A large number and variety of high performance
surfactants and polymers are now available for EOR
Chemical flooding is now being used for highly
viscous crudes, under higher salinity and higher
temperature conditions
Low cost and more effective lab methods have been
developed for chemical formulations
High recovery efficiency (>90% OOIP) has been
obtained in low permeability sandstone and dolomite
reservoir cores
The amount of surfactant needed to recovery the oil
has been reduced by a factor of 2 - 5 compared to
technology used in 70’s and 80’s
Summary (Cont’d)
Polymer flooding has been applied in
commercial scales
ASP and SP have only been applied
successfully in pilot scales
Many challenges are still remained in the
future in chemical flooding
Large resources are available for chemical
flooding
Harry L. Chang
THANK YOU!