1 / 21

Airborne Resistivity Mapping with Helicopter TEM: An Oil Sands Case Study

Airborne Resistivity Mapping with Helicopter TEM: An Oil Sands Case Study. S. Walker and J. Rudd, Aeroquest International Ltd. KEGS Symposium: Geophysical Contributions to New Discoveries Exploration ’07, Toronto, September 2007. Acknowledgements. Husky Oil

ellard
Download Presentation

Airborne Resistivity Mapping with Helicopter TEM: An Oil Sands Case Study

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Airborne Resistivity Mapping with Helicopter TEM:An Oil Sands Case Study S. Walker and J. Rudd, Aeroquest International Ltd. KEGS Symposium: Geophysical Contributions to New Discoveries Exploration ’07, Toronto, September 2007

  2. Acknowledgements • Husky Oil • Doug Oldenburg, Scott Napier and Roman Shekhtman (UBC-GIF) • Jim Henderson (AGL) • Aeroquest International

  3. Outline • Introduction • Geologic Setting • EM System Descriptions • Qualitative Data Comparison • Quantitative Comparison • Conclusions

  4. Introduction • Oil Sands prospect in Northern Alberta • Test survey flown for Husky Oil • Provided three lines of comparison data

  5. Geologic Setting Glacial cover Shale Oil Sands Limestone with/without salt water

  6. EM System Descriptions • AeroTEM IV (Aeroquest) • Helicopter TEM • 90 Hz, Triangular pulse, 190,000 Am2 • Z comp., 17 off-time gates (2.01 – 5.13 ms) • GeoTEM (Fugro) • Fixed-wing TEM • 30 Hz, Half-sine pulse, 690,00 Am2 • X comp., 14 off-time gates (4.58 – 15.59 ms) • Resolve (Fugro) • Helicopter FEM • 5 coplanar freq. (400, 1500, 6200, 25k, 100kHz)

  7. Qualitative Comparison • Common first step • Data or image based • Focus on northern most line Line 1 Line 2 Line 3

  8. Features in Data • Paleo-channel • Depth to the Clearwater • Surface detail • Bird height variation • Good first pass • But… AeroTEM Z (nT/s) GeoTEM X (pV/m2) CP Inphase (ppm) CP Quad (ppm)

  9. Spatial Resolution AeroTEM Z (nT/s) • Detailed view of paleo-channel data • Sampling Freq. • Survey speed • Effect of foot print • Need to do something else… GeoTEM X (pV/m2) CP Inphase (ppm) CP Quad (ppm)

  10. Quantitative Comparison • Rigorous 1D EM Inversion • What can we see and do we believe it? • Focus on specific soundings (1, 2, 3)

  11. Inversion Algorithm • EM1DFM and EM1DTM (UBC-GIF) • Model: log(σ), layered earth model • Data misfit • Chi squared, noise estimates important • Model Norm • Flattest and smallest model • Remember that solutions are non-unique!!

  12. Recovered Models (Stn 1) 10 Ωm ref. model 20 Ωm ref. model

  13. Recovered Models (Stn 2) 10 Ωm ref. model 20 Ωm ref. model

  14. Recovered Models (Stn 3) 10 Ωm ref. model 20 Ωm ref. model

  15. Depth of Investigation Index • Oldenburg and Li (1999) • if R = 0: m1 = m2 • More reliable model • as R → 1: m1, m2 → m1ref , m2ref • Less reliable model • Apply to our models and take a look…

  16. Models with DOI Index (Stn 1) 10 Ωm ref. model 20 Ωm ref. model DOI Index

  17. Models with DOI Index (Stn 2) 10 Ωm ref. model 20 Ωm ref. model DOI Index

  18. Models with DOI Index (Stn 3) 10 Ωm ref. model 20 Ωm ref. model DOI Index

  19. Pseudo 2D Model (Line 1) • Geologically interpretable • DOI helps know when to stop

  20. Pseudo 3D Model

  21. Conclusions • Helicopter TEM has worked well in the Oil Sands • High spatial resolution • Sensitive to both near surface and deep features • Pseudo 3D models • Start applying it in other areas

More Related