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, ï what types of hydrocarbons and, ï how are they distributed? What is the permeability (deliverability)? Will the formation produce water free? (what is irreducible saturation (BVI)) MRIL answers them all

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

hydrocarbon hydrocarbon Oilfield MRI (Relaxation Time Spectrum) Fluids Solids….invisible to MRI time, sec ……. irreducible movable water movable water movable water irreducible clay bound T 1 Magnetization no measurement T 2 relaxation times the measurement rock matrix dry clay

Magnetic Dipole Proton H Hydrogen N S NMR works with Protons - Hydrogen -> H 2 O and C x H y +++

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

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

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

Polarization Time T2T2 Decay Time T1T1 Magnetization T 1 characterizes the rate at which longitudinal magnetization builds up T 2 characterizes the rate at which transverse magnetization decays B0B0 MLML MTMT T 1 build-up and T 2 decay

NMR Experiment Timing MoMo 0 M  to B o (longitudinal component) M  to B o (transverse component) MoMo 0 RF field 0 B1B time, seconds TWTW TETE TXTX adapted from Murphy, D.P., World Oil, April 1995 T 1 = 400 msec T 2 = 250 msec

3 * T 1 = Tw 95% Polarization % Polarization *  = Measured Porosity t (s) % Polarization Gas: T 1 = 3s Water: T 1 = 0.33s T 1 Magnetization build up Light Oil: T 1 = 2s

T 1 Build-up T 2 decay Low Porosity Clean Cgr Sandstone Low Porosity Shaly Fgr Sandstone Higher Porosity Shaly Cgr Sandstone Time, sec. Effects of Chemistry and Texture on T 1 and T 2 (water filled)

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

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

time (ms) Amplitude (pu) Decay rate (1 / T 2 ) => rock & fluid information Measured signal decay TETE TETE Amplitude = Porosity

3 Relaxation Mechanisms Bulk Relaxation - T 2B Intrinsic Property of fluid Diffusion - T 2D Molecular Movement Surface Relaxation - T 2S Pore-walls cause rapid dephasing Effect of Each Mechanism is Additive Time, msec. Amplitude Echo Amplitude vs Time

T2T2T2T2 T2T2T2T2 T2T2T2T2 T2T2T2T2 T2T2T2T2 time time time time time Pore Size and T 2 (Water) T 2 = relaxation time constant. S = surface area of the pore. V = volume of the pore.  2 = relaxation rate constant.

Surface Relaxation Mechanism Water Filled Pores Time, msec. T 2 -1  S/V) Small Pore Sizes = Rapid Decay Rate Large Pore Sizes = Slow Decay Rate

Data Processing - Inversion T 2i are pre-selected: T 2i = 4, 8, 16, 32, 64, 128, 256, 512, MAP “Inversion” Processing T 2 [ms] Incremental Porosity [pu] T 2 Spectrum “Best Fit” Water-saturated rock:  2 = V/S  NUMAR Corp., 1995 BVI FFI

phi- NMR (pu)

Permeability Chart E S wir Porosity E (  x Swirr) increases k (md)

MRIL Permeability 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)

Differential Echo / Spectrum Method

Effect of Diffusion on T 2

Diffusion - Shifted Spectrum Method

Pay Recognition from EDM The Effect of Long T E

Density Porosity Neutron Porosity Effective Porosity Variable Density (milliseconds) T2 Distribution 20482

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