Tracers in heavy oil. A presentation by Tor Bjørnstad, Institute for Energy Technology, 2011

1. Heavy Oil Reservoirs: Fluid Tracing Challenges Tor Bjørnstad Institute for Energy Technology (IFE) Kjeller, Norway

5. Visionary thinking

6. Reservoir characterization Reservoir model incl. dynamic properties Geological (or static) reservoir model Well logs Biostratigraphy Sedimentology Geochemistry Seismics Reservoir modelling Tracer data Production data

7. Tracer Technology: Definitions

12. The “IFE Tracer Club”- different phases Tracer Technology development sponsored by major oil companies.

13. Tracers in reservoirs: Reservoir description and flow-field mapping

14. Water expels oil 8 km 2 km

15. Tracing of injection fluids P referential flow directions H orizontal and vertical communication between wells P ermeability strata S weep volumes L arge-scale hetero-geneities Injection well Production well Stratified reservoir

16. Field tracer production profiles P roduction curves for HTO in various production wells also illustrating how break-through has been missed in two cases D esign of experi-ment done with ECLIPSE on existing reservoir model FROM WELLS IN A NORTH SEA RESERVOIR 0 0.4 0.8 1.2 1.6 2 2.4 (Thousands) TIME FROM FIRST INJECTION (DAYS) 2.6 2.4 2.2 2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 INJ.

19. Tracer response after WAG PMCH responses from I2 PMCH P4 P5 P7 P8 P9 I2 I3 P6

20. Tracer Types, Sampling, Analysis and Modeling

21. Isotopic ratio tracers Example: Ratio of 12 C and 13 C which varies in different fluids and C-containing matter. The standard is an established reference, such as ocean water .

22. Radioactive tracers for IWTT Organic molecules : CH 2 T OH, 14 C H 3 OH CH 3 14 C HOHCH 3 , CH 3 C T OHCH 3 Inorganic molecules: H T O, 22 Na + , 125 I - , ( 131 I - ), ( 82 Br - ), 36 Cl - , 35 S CN - , S 14 C N - , ( 35 S O 4 2- ), 56 Co (CN) 6 3- , 57 Co (CN) 6 3- , 58 Co (CN) 6 3- , 60 Co (CN) 6 3- Co(CN) 5 ( 14 C N) 3-

23. Non-radioactive polyfluorinated interwell water tracers H F COOH H H H H F COOH H H H F H COOH F H H H H COOH F F H H H COOH H F F H F COOH H H F H F COOH F F F H F COOH H H H

24. “ Water” samples from flow line

25. Non-radioactive gas tracers P erfluorinated cyclic hydro-carbons with coordinated light hydrocarbon (methyl) groups are excellent gas tracers PMCP PMCH CARBON FLUORINE 1,2,4-PTMCH PDCB 1,3-PDMCH

26. Gas Tracer sample container General version, pressurized New, for PFC-tracers, non-pressurized

27. GC-MS/MS

28. HPLC spectrometer

29. Fluorescense of produced waters and tracers Gullfaks water IFE-WTN-1,3 IFE-WTN-1,3,6 Fluorescein Tap water Heidrun water IFE-WTN-2,7 Emission wavelength (nm) Exitation wavelength (rel) Norne water

30. Isotope mass spectrometer

31. LSC scintillation vial 12 mL scintillation cocktail + 8 mL distilled sample intimately mixed

32. Liquid scintillation counting - analysis of HTO in produced water Channel number (Energy) Counting rate HTO spectrum, sample 1: 82 ± 4 Bq/l HTO spectrum, sample 2: 10 ± 2 Bq/l Background spectra

33. Heavy Oil Production – Tracing Challenges

34. Oil Classification Type API gravity Density (kg/m 3 ) Viscosity (cP) Bitumen << 10 1000 ++ > 10.000 Extra heavy oil < 10 1000 + > 1000 Heavy oil 10 – 22.3 920 - 1000 > 100 Medium oil 22.3 – 31.1 870 - 920 10 - 100 Light oil > 31.1 < 870 < 10

35. Cyclic Steam Stimulation (CSS) Steam injection Steam soaking Backpro- duction

37. Toe-to-Heel Air Injection (THAI) Cold heavy oil Combustion zone Coke zone Mobil oil Injected air and water

39. SAGD principle SAGD = Steam-Assisted Gravity Drainage Steam injection Oil production Vapor heats up a compartment around the well and mobilizes the oil The mobilized oil is drained into the lower production well

40. Statement “ D uring the startup and early operation of horizontal SAGD wells, it is important to understand the flow distribution of bitumen and water along the horizontal reservoir interval. I f this distribution is understood, the distribution of steam, injected either at the heel or toe of the steam injector, can be adjusted to optimize the startup and early operation of the SAGD pair”. JPT

41. Tracers for SAGD Requirement: Tracers stable at temperatures of 200-300 C For water vapor: H T O, CH 2 T OH For water cond. phase: Naphtalene-sulphonic acids For steam/gas phases: Various PFCs

42. Low Temp. Solvent (VAPEX) Production well Injection well Draining diluted and deasphalted oil

43. Tracers for VAPEX presently in pilot tests Requirement: Temperature is not a stability issue for the tracers but they must be stable against biodegradation For light injected HC: T - or 14 C -labelled propane, isopropane, butane, isobutane, pentane etc. For cond. aq-phase: FBA, Naphtalene-sulphonic acids, H T O and several more

44. SAGD and VAPEX combined -high-temperature recovery – in pilot stage Production well Injection well Mobilized oil

45. Tracers for combined SAGD and VAPEX Requirement: Tracers for water vapor, water condensed phase and gas phase stable at temperatures of 200-300  C as for SAGD Additional: Radiolabelled light HC tracers as for VAPEX

46. Outlook

48. Tracer molecules become constantly more complex Are these among the future candi-dates?? Borrowed from Nick D. Kim

49. Fluorescent and radioactive nano-particles Particle core emission Particle core and functional layer emission Particle core and multifunctional layer emission

50. Surfactant: Alpha-olefine sulphonate labelled with radioactive nuclides CH 3  (CH 2 ) 8  CH = CH  CH 2  35 S O 3 - Na + OH CH 3  (CH 2 ) 8  CH  CH 2  CH 2  SO 3 - Na + OH 14 C H 3  (CH 2 ) 8  CH  CH 2  CH 2  SO 3 - Na + OH CH 3  (CH 2 ) 8  C T  CH 2  CH 2  SO 3 - Na +

51. Tor Bjørnstad Tracer injection pump IFE personnel Tracer operations in the North Sea 1

52. Tor Bjørnstad Learning to operate the gas tracer sampling kit

53. Hybrid End