Harry L. Chang

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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
Harry L. Chang
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
Harry L. Chang
Recent Advancements
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Chemicals
Laboratory Studies
Simulation and Simulators
Project Design and Implementation
Facilities, Monitoring, and Evaluation
More Field Experiences
Harry L. Chang
EOR Chemicals
 Polymers and related chemicals
 Surfactants
 Co-surfactants
 Co-solvents
Harry L. Chang
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]
Harry L. Chang
Improved Laboratory Techniques
 Phase behavior/solubalization ratio
 High temperature and live oil
 Core flood techniques
Harry L. Chang
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
Harry L. Chang
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
Harry L. Chang
Simulation and Simulators
 Mechanistic model for core flood and
pattern simulation
 Calibration and field scale simulation
 Advanced simulators
Harry L. Chang
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
Harry L. Chang
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
Harry L. Chang
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
Harry L. Chang
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
Harry L. Chang
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
Harry L. Chang
Field Examples
 Daqing
 Karamay
 ASP pilot simulation
Harry L. Chang
ASP Pilot Tests Conducted in
Daqing Oilfield
Harry L. Chang
ASP Results in Daqing
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High incremental recovery
Severe emulsion production
Severe scale production
SP with A instead of ASP?
One of the most difficult oil for SP
flooding
Harry L. Chang
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
Harry L. Chang
Chemical Injection Facilities
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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
Harry L. Chang
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
49
ST200508
SPE Logo
50
ST200508
SPE Logo
51
ST200508
SPE Logo
52
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?
Harry L. Chang
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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Harry L. Chang
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!
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