Chemical kinetics


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Chemical kinetics

  1. 1. Chemical EOR Progress inChina Advances and Challenges Harry L. Chang
  2. 2. Outline of Presentation Overview Recent advancements Chemical EOR in China  Polymer flooding  ASP flooding  Facilities Some controversial issues and challenges Summary
  3. 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. 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. 5. Recent Advancements Chemicals Laboratory Studies Simulation and Simulators Project Design and Implementation Facilities, Monitoring, and Evaluation More Field Experiences Harry L. Chang
  6. 6. EOR Chemicals Polymers and related chemicals Surfactants Co-surfactants Co-solvents Harry L. Chang
  7. 7. Improvements on Polymers (UT David Levitt Dissertation) Harry L. Chang
  8. 8. Improved Laboratory Techniques Phase behavior/solubalization ratio High temperature and live oil Core flood techniques Harry L. Chang
  9. 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. 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. 11. Interface FluidityIncreasing Electrolyte Concentration
  12. 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. 13. Simulation and Simulators Mechanistic model for core flood and pattern simulation Calibration and field scale simulation Advanced simulators Harry L. Chang
  14. 14. Chemical EOR in China
  15. 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. 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. 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. 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. 19. Oil Production by Polymer Flooding Daqing Oilfield, China 1000 900 PF Ann. Rate, mmbblsOil 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. 20. A Typical PF Field Performance
  21. 21. Typical Pressure and Polymer Production
  22. 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. 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. 24. Viscosity Data of KYPAM Polymer Concentrati on
  25. 25. Performance of KYPAM Polymers
  26. 26. Performance of KYPAM Polymers
  27. 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. 28. Field Examples Daqing Karamay ASP pilot simulation Harry L. Chang
  29. 29. ASP Pilot Tests Conducted in Daqing Oilfield Harry L. Chang
  30. 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. 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. 32. ASP Pilot Test Well Pattern, 2Z-B9-3 Well Group Karamay Oil Field (SPE 64726)
  33. 33. ASP Slug Design and Injection Sequence (SPE 64726) PAM PAM
  34. 34. Modelling Core Flood - Karamay ASP Project
  35. 35. Modelling Coreflood (UTCHEM) - Karamay ASP Project
  36. 36. Modelling of Pilot Area Performance (SPE 39610 and 64726)
  37. 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. 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. 39. A Polymer Test Injection Site, SPSW Facilities
  40. 40. SPMW Polymer injection system Spec.: 16 Mpa, 60 m3/hr, polymer conc., 1000 mg/l , 27 injection wellsSPMW Polymer injection pumpsSpec.: 16 Mpa, 4 m3/hr,And 5000 mg/l polymer
  41. 41. ST200508 SPE Logo 41
  42. 42. Large-Scale Polymer Dispersion/Mixing 42
  43. 43. Polymer Dispersion Polymer Mixing
  44. 44. ASP Injection Units Prior to Shipping
  45. 45. An ASP Injection Station with 70 Wells
  46. 46. Produced Fluid Treatment FacilitiesASP Produced Fluid Treatment, 24,000 m 3 /d
  47. 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. 48. SPE Logo 48
  49. 49. A Polymer Handling System Designed byChemor Tech and Fabricated by Dafeng/COT in China
  50. 50. ST200508 SPE Logo 50
  51. 51. ST200508 SPE Logo 51
  52. 52. ST200508 SPE Logo 52
  53. 53. ST200508 SPE Logo 53
  54. 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. 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. 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. 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. 58. THANK YOU!