The NMR T2 interpretation wizard turns an existing, already inverted T2 array distribution into ordinary well-log curves for one well. It can save any combination of NMR porosity, bound and free fluid, T2 logarithmic mean, and SDR and Coates permeability. It does not process raw echoes or invert T2 data.

Prepare the distribution

Use a T2 array channel whose amplitudes are calibrated incremental porosity per bin, expressed as a fraction or percent. Signal-amplitude and density-per-T2 distributions cannot be interpreted as porosity by this wizard. An array channel may be imported from DLIS; a generic array appears in the source list only if you identify it as a T2 distribution yourself.

Every bin needs a positive physical T2 centre and a bin-axis unit of milliseconds or seconds. If the axis is absent or inconsistent with the array, open the source log file's Array channels dialog. For an imported file, use Log Mode > LAS files in the Data manager, right-click the source file and choose Set image orientation.... Select the channel, use Bin axis > Edit... to enter exactly one centre per bin, separated by spaces or commas, and set Units: to ms or s. Then return to the interpretation wizard.

Calculate and save

1. On the Petrophysics ribbon, click NMR T2 in Properties.
2. Choose the Well and T2 distribution. Check Amplitudes are calibrated incremental porosity per bin only after confirming what the source values represent. Review Amplitude unit: Fraction (v/v) or Percent (p.u.). A unit inferred from the channel can be changed here.
3. Set T2 cutoff (ms), initially 33 ms. Review the editable SDR and Coates coefficients and permeability limits if your interpretation requires different values.
4. Under Output curves, select at least one result in the Save column and edit its Curve name if needed. Selected names must be nonempty and distinct. Click Calculate to inspect the interpreted and rejected row counts and output ranges, then click Save to calculate and write the selected curves.

If an output name already exists in the well, Yes replaces the existing curve, No keeps it and saves the new curve under a versioned name, and Cancel returns to the wizard.

Output curves

• NMR_PHI: total NMR porosity, fraction (v/v).
• BVI: bulk volume irreducible from bins at or below the cutoff, fraction (v/v).
• FFI: free fluid index above the cutoff, fraction (v/v).
• T2LM: amplitude-weighted logarithmic mean T2, milliseconds.
• K_SDR: SDR permeability, mD.
• K_COATES: Coates permeability, mD.

The wizard converts seconds to milliseconds and percent amplitudes to fractions. It sums the incremental amplitudes for NMR_PHI, assigns a whole bin to BVI when its centre is at or below the cutoff, and obtains FFI from NMR_PHI minus BVI. It does not normalize amplitudes or multiply them by bin width. SDR and Coates use the same permeability methods described in Permeability; needed intermediate values are calculated even when their curves are not selected for saving.

Invalid samples and scope

A missing, nonfinite or negative amplitude makes all results null at that depth; the wizard does not use the remaining bins as a partial spectrum. An all-zero spectrum gives zero NMR_PHI, BVI and FFI, but null T2LM and permeability. Coates permeability is null when BVI or FFI is zero. If a permeability result is undefined, otherwise valid porosity, fluid and T2LM results remain available.

Saved curves follow the source array's depth samples without resampling, and the source distribution is unchanged. This wizard processes one well at a time and has no batch or workflow command.