This document summarizes chemical EOR progress and challenges in China. It outlines recent advancements in chemicals, laboratory studies, simulation techniques, and field applications of polymer flooding and ASP flooding. Polymer flooding has been applied successfully at large scales in the Daqing and Shengli oilfields in China, stabilizing production and doubling polymer usage over 10 years. ASP flooding also shows potential but faces challenges with emulsions, scaling, and stability. Overall chemical EOR continues to advance but challenges remain around applications at higher temperatures and developing low-cost solutions.

1. Chemical EOR Progress in
China Advances and Challenges
Harry L. Chang
Harrylchang@chemortech.com
www.chemortech.com

2. Outline of Presentation
 Overview
 Recent advancements
 Chemical EOR in China
 Polymer flooding
 ASP flooding
 Facilities
 Some controversial issues and
challenges
 Summary

3. 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

4. General Understanding
 Polymer flooding (PF): A mature EOR process
 Polymer gels: Used successfully in water shut-
off 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

5. Recent Advancements
 Chemicals
 Laboratory Studies
 Simulation and Simulators
 Project Design and Implementation
 Facilities, Monitoring, and Evaluation
 More Field Experiences
Harry L. Chang

6. EOR Chemicals
 Polymers and related chemicals
 Surfactants
 Co-surfactants
 Co-solvents
Harry L. Chang

7. Improvements on Polymers
(UT David Levitt Dissertation)
Harry L. Chang

8. Improved Laboratory
Techniques
 Phase behavior/solubalization ratio
 High temperature and live oil
 Core flood techniques
Harry L. Chang

9. 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

10. 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

11. Interface Fluidity
Increasing Electrolyte Concentration

12. Core Flooding
 High oil recovery
>90% Sorw, or Sorc<0.04
 Adequate mobility control
 Good surfactant/polymer transport
 Low surfactant retention
Harry L. Chang

13. Simulation and Simulators
 Mechanistic model for core flood and
pattern simulation
 Calibration and field scale simulation
 Advanced simulators
Harry L. Chang

14. Chemical EOR in China

15. 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

16. 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

17. 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

18. 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

19. Oil Production by Polymer Flooding
Daqing Oilfield, China
1000
900 PF Ann. Rate, mmbbls
Oil Rate by Polyme r Flooding, mmbbls
800 Cum. Prod., mmbbls
700
600
500
400
300
200
100
0
1993 1995 1997 1999 2001 2003 2005 2007 2009
Ye ar

20. A Typical PF Field Performance

21. Typical Pressure and Polymer
Production

22. Oil Production by Polymer Flooding
Shengli Oilfield, China
200
PF Ann. Rate, mmbbls
180
Cum. Prod., mmbbls
Oil Rate by Polymer Flooding, mmbbls
160
140
120
100
80
60
40
20
0
1997 1999 2001 2003 2005 2007 2009
Year

23. 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

24. Viscosity Data of KYPAM Polymer
Concentrati
on

25. Performance of KYPAM Polymers

26. Performance of KYPAM Polymers

27. 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

28. Field Examples
 Daqing
 Karamay
 ASP pilot simulation
Harry L. Chang

29. ASP Pilot Tests Conducted in
Daqing Oilfield
Harry L. Chang

30. 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
Harry L. Chang

31. 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

32. ASP Pilot Test Well Pattern, 2Z-B9-3 Well Group
Karamay Oil Field (SPE 64726)

33. ASP Slug Design and Injection
Sequence
(SPE 64726)
PAM
PAM

34. Modelling Core Flood - Karamay ASP
Project

35. Modelling Coreflood (UTCHEM) - Karamay
ASP Project

36. Modelling of Pilot Area Performance
(SPE 39610 and 64726)

37. 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

38. 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
Harry L. Chang

39. A Polymer Test Injection Site, SPSW
Facilities

40. 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

41. ST200508
SPE Logo 41

42. Large-Scale Polymer
Dispersion/Mixing
42

43. Polymer Dispersion Polymer Mixing

44. ASP Injection Units Prior to
Shipping

45. An ASP Injection Station with 70 Wells

46. Produced Fluid Treatment
Facilities
ASP Produced Fluid Treatment, 24,000 m 3 /d

47. 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
• Automation: Allen-Bradley PLC based with full PID
Loop control for accurate chemical recipe control and
data collection
• Special Systems Included:
• R-O water softening
• Fe removal system
• Heat exchanger system for high temp fluid injection

48. SPE Logo 48

49. A Polymer Handling System
Designed by
Chemor Tech and Fabricated by
Dafeng/COT in China

50. ST200508
SPE Logo 50

51. ST200508
SPE Logo 51

52. ST200508
SPE Logo 52

53. ST200508
SPE Logo 53

54. 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

55. 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
Harry L. Chang

56. 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

57. 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

58. THANK YOU!