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Cold production footprints of heavy oil on time-lapse seismology: Lloydminster field, Alberta

Cold production footprints of heavy oil on time-lapse seismology: Lloydminster field, Alberta. Sandy Chen*, L.R.Lines, J. Embleton, P.F. Daley, and L.F.Mayo. Outline. Mechanism of heavy oil cold production Cold production geological models

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Cold production footprints of heavy oil on time-lapse seismology: Lloydminster field, Alberta

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  1. Cold production footprints of heavy oil on time-lapse seismology: Lloydminster field, Alberta Sandy Chen*, L.R.Lines, J. Embleton, P.F. Daley, and L.F.Mayo

  2. Outline • Mechanism of heavy oil cold production • Cold production geological models • Geophysical response of a cold production reservoir • Time-lapse seismic modeling of cold production drainage footprints

  3. Mechanics of heavy oil cold production -Non-thermalprocess - Oilandsandproduced simultaneously

  4. With sand Without sand Production rates with and without sands • Wormhole network growth • Foamy oil drive (Sawatzky, 2002)

  5. Wormhole network Depth about 500 – 700m Wormhole growth pattern (Miller et al., 2001) Courtesy of KUDU Oil Well Pumps

  6. Wormhole characteristics 10cm “wormhole” created in reservoir lab simulation (Tremblay et al. ARC,1998 SPE/DOE symposium & EAGE Symp., 1999)

  7. Foamy oil characteristics Single propagating wormhole in a sandstone (Dusseault,1994) Bubble wormhole pipe Foamy oil mechanism (D. Greenidge, Imperial Oil Resources)

  8. Amplitude anomalies in drainage region 400m oil 9m3/d cum oil 9E6m3 cum gas 2E6m3 oil 9m3/d cum oil 12E6m3 cum gas 1E6m3 oil 10m3/d cum oil 14E6m3 cum gas 1E6m3 oil 7m3/d cum oil 23E6m3 cum gas 2E6m3 oil 8m3/d cum oil 14E6m3 cum gas 2E6m3 oil 5m3/d cum oil 8E6m3 cum gas 2E6m3 oil 10m3/d cum oil 24E6m3 cum gas 2E6m3 3D Seismic Amplitude Map in Lloydminster Filed after 9 years of production (Mayo,1996)

  9. It is useful for engineers and geologists to know the size and distribution of drainage regions Drainage footprint scenario for the cold production wells in a small southwest Saskatchewan heavy oil pool (Sawatzky, 2002)

  10. Simplified drainage model (vertical wellbore) Post-production reservoir state Oil, water & foamy oil initial reservoir state Oil & water wormholes 3D map view borehole Undisturbed region Drainage region Net Pay zone 2D cross-section

  11. =2.26g/cm3, Vp=2496m/s Top Mannville =2.37g/cm3, Vp=3227m/s Top McLaren =2.16g/cm3, Vp=2795m/s Production Fm Bottom McLaren =2.40g/cm3, Vp=3261m/s Pre-production reservoir model 2D synthetic seismogram of wormholes Well log in Lloydminster Field

  12. Porosity Resistivity Gamma Most likely net pay zones Two main net pays (red) in Mclaren reservoir sand. Upper sand, 5m net pay, lower sand 3m.

  13. Well =2.26g/cm3, Vp=2496m/s Top Mannville =2.37g/cm3, Vp=3227m/s Top McLaren =2.16g/cm3, Vp=2795m/s Production Fm Bottom McLaren Drainage region with Vp=????, =???? =2.40g/cm3, Vp=3261m/s Post-production model with drainage region ? Drainage regions 5m and 3m thick, and 200m and 300m long

  14. Recall that fluids state changes during production: Before production: oil & water After the start of production: Foamy oil with gas bubbles, oil & water

  15. Assumptions of mixed fluid states Application of average fluid mixture states between the harmonic fluid state and the ‘Patchy’ weighted fluid (Reuss average & Voigt model) Harmonic, Reuss average, lower bound Patchy, Voigt average, upper bound Here, Kg, Ko, Kw are derived from the methods demonstrated by Batzle and Wang (1992)

  16. Applications of Gassmann’s Equation • Ks=36Gpa • The shear modulus is derived using dipole logs from Pikes Peak Area

  17. In-situ reservoir parameters after 3-years of production (Courtesy of Alberta Research Council) (assuming no change in porosity and water saturation)

  18. Physical properties of the drainage area

  19. Well =2.26g/cm3, Vp=2496m/s Top Mannville =2.37g/cm3, Vp=3227m/s Top McLaren =2.16g/cm3, Vp=2795m/s Production Fm Bottom McLaren Vp=2570m/s, =2.13g/cm3 =2.40g/cm3, Vp=3261m/s Post-production model with drainage region

  20. without drainage with drainage difference Zero-offset seismic sections frequency bandwidth 200Hz (reverse display)

  21. Impact of frequency on vertical resolution of seismic images of the drainage areas

  22. Conclusions • The presence of foamy oil is the key factor, resulting in amplitude anomalies. Time-lapse seismology can be a very useful tool for detecting cold production drainage patterns • The limitation of seismic frequency determines the images of the drainage footprints

  23. Future Work - Wormholes • Wormhole effects on reservoir rock, especially when large amounts of sands are produced. S-wave may be sensitive to the presence of wormholes

  24. Acknowledgements • COURSE Project • CREWES • Alberta Research Council • Dr. Ron Sawatzky

  25. Backup slides

  26. P-wave & S-wave Velocities v.s. Gas Saturation P=3Mpa P=3Mpa Sg=0.1

  27. Amplitude changes relative to bed thickness fdom200Hz, 13m fdom100Hz, 26m Amp decrease (Widess,1973)

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