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MRIL OVERVIEW

MRIL OVERVIEW. Team One NUMAR / HALLIBURTON. Crucial Formation Evaluation Questions. What is the storage capacity (  e and  t ) in a Complex Lithology Environment ? Are there hydrocarbons, what types of hydrocarbons and, how are they distributed?

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MRIL OVERVIEW

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  1. MRIL OVERVIEW Team One NUMAR / HALLIBURTON

  2. Crucial Formation Evaluation Questions • What is the storage capacity (e and t ) in a Complex Lithology Environment ? • Are there hydrocarbons, • what types of hydrocarbons and, • how are they distributed? • What is the permeability (deliverability)? • Will the formation produce water free? (what is irreducible saturation (BVI)) MRIL answers them all

  3. Medical MRI “Thin Slice” Image Only Fluids are Visible H

  4. irreducible rock matrix movable water hydrocarbon dry clay clay bound clay bound irreducible T2 relaxation times the measurement movable water hydrocarbon T1 Magnetization no measurement time, sec. 0 1 2 3 4 5 6 8 9 10 11 12 13 14 ……. Oilfield MRI(Relaxation Time Spectrum) Fluids Solids….invisible to MRI

  5. N S H Hydrogen Proton Magnetic Dipole NMR works with Protons - Hydrogen -> H2O and CxHy+++

  6. N N N S S N N S N S S N N S S S N N N S N S N S S S N Bo S t = 0 Random Orientation in Natural State

  7. N N N S S N N S S N N N S N N S S N S S N Wait time (sec) S N S S S M N S Magnetization Buildup Bo Bo=External FieldM=Bulk Net Magnetization t = 0.75 sec

  8. N N N S N S N S N S N S N N N S N S M S S N Wait time (sec) S N N S S S S Buildup at 95 % polarization Bo Bo=External Field M=Bulk Net Magnetization t = 6.0 sec

  9. ML B0 MT T1 Polarization Time Magnetization T2 Decay Time T1 build-up and T2 decay T1 characterizes the rate at which longitudinal magnetization builds up T2 characterizes the rate at which transverse magnetization decays

  10. NMR Experiment Timing Mo T1 = 400 msec M || to Bo (longitudinal component) 0 TW Mo T2 = 250 msec M ^ to Bo (transverse component) 0 TE TX B1 RF field 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 time, seconds adapted from Murphy, D.P., World Oil, April 1995

  11. 3 * T1 = Tw 95% Polarization T1 Magnetization build up Water: T1 = 0.33s 100 80 60 40 20 0 Light Oil: T1 = 2s Gas: T1 = 3s % Polarization 0 1 2 3 4 5 6 7 8 9 10 11 12 t (s) % Polarization *  = Measured Porosity

  12. Effects of Chemistry and Texture on T1 and T2 (water filled) Low Porosity Clean Cgr Sandstone T1 Build-up T2 decay Low Porosity Shaly Fgr Sandstone Higher Porosity Shaly Cgr Sandstone 0 1 2 3 4 5 6 7 8 9 10 Time, sec.

  13. MRIL in Wellbore Borehole MRIL Probe Sensitive Volume Cylinders (each 1 mm thick at 1 mm spacing) 24 “ Pulsing RF and receiving RF Antenna Permanent Magnet and Field  16”

  14. Sonde Sleeve MRIL Diameter of Investigation Multi - Frequency Series C Tool Frequency 1 Frequency 2 Borehole Wall Frequency 3 Formation RF Antenna Magnet S N 1 2 Mud 3 6” 16” ã NUMAR Corp., 1995

  15. Measured signal decay TE Amplitude= Porosity Amplitude(pu) Decay rate (1 / T2) => rock & fluid information time (ms) TE

  16. 3 Relaxation Mechanisms Echo Amplitude vs Time Effect of Each Mechanism is Additive Bulk Relaxation - T2B Intrinsic Property of fluid Amplitude Diffusion - T2D Molecular Movement Surface Relaxation - T2S Pore-walls cause rapid dephasing Time, msec.

  17. Pore Size and T2(Water) time T2 T2 time T2 = relaxation time constant. time T2 S = surface area of the pore. V = volume of the pore. T2 time 2 = relaxation rate constant. T2 time

  18. Surface Relaxation MechanismWater Filled Pores Small Pore Sizes = Rapid Decay Rate Large Pore Sizes = Slow Decay Rate T2 -1 @ r (S/V) Time, msec.

  19. MAP “Inversion” Processing Spin-echo data T2 Spectrum “Best Fit” FFI BVI 35 30 25 20 Incremental Porosity [pu] 15 10 5 0 0 50 100 150 200 250 300 T2 [ms] Water-saturated rock: rT2 = V/S ã NUMAR Corp., 1995 Data Processing - Inversion T2i are pre-selected: T2i = 4, 8, 16, 32, 64, 128, 256, 512, 1024...

  20. 40 35 30 25 20 15 10 5 0 0 5 10 15 20 25 30 35 40 phi-core (pu) phi-NMR (pu)

  21. 1000 100 10 1.0 Permeability Chart E-4 0.5 E - 4 0.4 0.3 Porosity (f x Swirr) increases 0.2 0.1 k (md) 0 0 0.2 0.4 0.6 0.8 1 Swir

  22. MPERM = ((MPHI/10)2 (MFFI/MBVI))2 MPHI - MRIL Porosity (porosity units) MBVI - MRIL Bulk Volume Irreducible MFFI - MRIL Free Fluid Index MPERM - Permeability (millidarcies) MRIL Permeability

  23. 10000 1000 100 K_NMR (mD) 10 1 0.1 0.01 0.01 0.1 1 10 100 1000 10000 K_air (mD)

  24. Differential Echo / Spectrum Method

  25. Effect of Diffusion on T2

  26. Diffusion - Shifted Spectrum Method

  27. Pay Recognition from EDMThe Effect of Long TE

  28. Density Porosity 0 60 0.2 150 20 60 Gamma Ray (GAPI) Shallow Resistivity T2 Distribution 60 18 20 0.2 BVI Deep Resistivity Caliper (in) Variable Density (milliseconds) 100 20 SP (mv) 60 2 2048 20 Permeability (md) 2000 Depth 100 Bins 1 - 8 (PU) 0 XX200 0 Neutron Porosity 0 8 0 -100 Effective Porosity 0

  29. Pick your choice • What’s new ? • Low resistivity pay • Extra pay identified • Shale, Huh ? • Integrating core data and MRIL data

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