Chemical EOR Progress in China Advances and Challenges

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. 50 40 1500 ppmHPAM polymer, 23 °C, 11 s-1 30 NaCl Viscosity[cp] 20 9:1 NaCl/CaCl2 10 ElectrolyteConcentration [TDS, ppm] 0 0 50,000 100,000 150,000 200,000 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 • Determinemicroemulsion viscosities • Specific surfactant(s) can be tailored for specific oils Harry L. Chang

10. 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 An Excellent ME Phase Behavior

11. Interface Fluidity

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 FloodingDaqing Oilfield, China

20. A Typical PF Field Performance

21. Typical Pressure and Polymer Production

22. Oil Production by Polymer FloodingShengli Oilfield, China

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 viscosity Concentration

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 GroupKaramay 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

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42. Large-Scale Polymer Dispersion/Mixing 41

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 m3/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

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

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