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Chemical EOR Progress in China Advances and Challenges Harry L. Chang

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Presentation on theme: "Chemical EOR Progress in China Advances and Challenges Harry L. Chang"— Presentation transcript:

1 Chemical EOR Progress in China Advances and Challenges Harry L. Chang

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) 1500 ppm HPAM polymer, 23 °C, 11 s ,000100,000150, ,000 Electrolyte Concentration [TDS, ppm] Viscosity [cp] NaCl 9:1 NaCl/CaCl 2 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, %:

11 Interface Fluidity

12  High oil recovery >90% S orw, or S orc <0.04  Adequate mobility control  Good surfactant/polymer transport  Low surfactant retention Core Flooding 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

20 A Typical PF Field Performance

21 Typical Pressure and Polymer Production

22 Oil Production by Polymer Flooding Shengli 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 Concentration viscosity

25 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

34 Modelling Core Flood - Karamay ASP Project

35 Modelling Coreflood (UTCHEM) - Karamay ASP Project

36 Modelling of Pilot Area Performance (SPE 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 pumps Spec.: 16 Mpa, 4 m 3 /hr, And 5000 mg/l polymer SPMW Polymer injection system Spec.: 16 Mpa, 60 m 3 /hr, polymer conc., 1000 mg/l , 27 injection wells

41 ST SPE Logo40

42 41 Large-Scale Polymer Dispersion/Mixing

43 Polymer DispersionPolymer 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 Logo47

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

50 ST SPE Logo49

51 ST SPE Logo50

52 ST SPE Logo51

53 ST SPE Logo52

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 (>90 o C  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 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


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